Thyroidcancerhelp Yahoo Group
Dr. Ain served as one of the first ThyCa medical advisors and has been the ThyCa listserve medical advisor for over 12 years. He now runs his own Yahoo listserve to service thyroid cancer patients’ specific questions. The group is called ThyroidCancerHelp. To open the ThyroidCancerHelp Yahoo group in a new browser window, please click this link.
Disclaimer
The medical information that is provided on this site is based upon the specific medical expertise of Dr. Kenneth Ain. Please refer to his Curriculum Vitae for documentation of his experience. Where appropriate, additional references to the medical literature are cited in specific answers to listed questions. This information is provided to users as a free service for their own education and is not intended to provide specific care or advice that should be provided by their own physicians.
This site is supported directly by Dr. Kenneth Ain. No advertising funding is accepted.
This site does not maintain or record any personal information or identifiers of visitors who utilize its information or services.
Please find below, answers to the most common questions on ThyroidCancerHelp (to date) which have been arranged alphabetically. Use the alphabet below to browse topics. To search key words, use your browser's FIND function. The original questions and answers are archived on ThyroidCancerHelp which any member may access.
Last update: August, 2008
TOPICS (answers only)
A B C D E F G H I L M N O P R S T U V X Z
99m-Tc is not used in thyroid cancer patients
99mTc-pertechnetate should not be used in patients with known thyroid carcinoma. It is only used for scanning thyroid glands in patients with thyroid glands that are still in their neck. Although convenient for the nuclear medicine physician, it is generally inferior to radioactive iodine for scanning thyroid glands.
—ThyroidCancerHelp, July, 2007
A
Age of diagnosis as a risk factor
There are a number of epidemiologically studies performing something termed "multivariate analysis" to try to see what patient features have predictive value in determining outcome risk.
The many, many published studies are usually retrospective and thus limited in their power; however, a majority have determined common risk factors: Tumor size: the bigger the tumor the higher the risk; Tumor invasion: if it invades tissues outside of the thyroid beware; Distant metastases: seems obvious, but if it spreads to your lungs or brain, it's not good; Male sex: on average, men who get thyroid cancer have worse outcomes than women with the same extent of disease; Patient age: dedifferentiated tumors are more likely to be discovered in older people. There is a difference between studies in the particular age. Some studies say that it is 45 years, some say 50 years, some say older. Since I'm in my 50's, I'd prefer not to refer to this age as "older."
There are a number of other factors, but I think that the picture is clear.
—ThyroidCancerHelp, August, 2007
Alcohol ablation of recurrent tumor
When searching for the site(s) of residual/recurrent thyroid cancer, known to be present because of increased thyroglobulin, many methods are often used. Ultrasound is very useful in the neck region, particularly since more than half the time, there is persistent disease in this region. When a suspicious node or mass is found, particularly when verified by fine needle aspiration biopsy, there are several approaches. In most circumstances, we advise that an experienced surgeon approach the lymph node compartments in that region of the neck, not only to remove the particular mass/node but also to remove additional lymph nodes that often contain disease not made evident on the ultrasound. If these sites of disease had already been confirmed as no longer taking up radioactive iodine, follow-up treatment with external beam radiation is often a consideration.
Injecting alcohol (ethanol ablation) into the cancer-containing lymph node or mass to destroy it is a method that we sometimes apply when the patient is too fragile to tolerate another surgical procedure or the site of the tumor is in a region that is not easily approached by surgery. It has limitations in that it presumes that the ultrasound has been definitive in defining all of the tumor sites in that region. It also requires fairly definitive confidence in the biopsy diagnosis that the site contains tumor. There are often many alternative approaches to dealing with this problem and each of them have their strengths and weaknesses.
—ThyroidCancerHelp, October, 2007
Amifostine and XRT
Amifostine should not be used with I-131 therapy. On the other hand, although it might be helpful to decrease salivary gland damage when used with external beam radiotherapy, there are a number of issues with its use that should be carefully discussed with the radiotherapist.
—ThyroidCancerHelp, September, 2007
Anaplastic thyroid cancer: A primer
Much of my research is on the cell biology and treatment approaches for anaplastic thyroid cancer (ATC). It is very important to have the pathology re-checked by an experienced thyroid pathologist since it is very common that less-experienced (in thyroid cancer) pathologists make errors in this diagnosis. There are several points that should be made concerning this type of thyroid cancer:
1) There is sufficient evidence to say that anaplastic cancer is a terminal dedifferentiation of a pre-existing papillary or follicular thyroid cancer. In my experience, the most likely type of cancer to undergo an anaplastic transformation is tall cell variant papillary thyroid cancer, although other types can do so. There are a number of genetic changes in the thyroid cancer that are thought to underlie this process. Typically, anaplastic thyroid cancer arises in the context of a pre-existing differentiated cancer that has not been excised or treated for a very long time. Sometimes this cancer has independently spread through the body and there might end up being “two types” of thyroid cancer existing simultaneously in the same person. We tend to focus exclusively on the anaplastic thyroid cancer since this is the most dangerous one. In the very rare (unfortunately) individuals who survive their anaplastic cancer more than two years, we consider the ATC to be “cured” because in nearly all cases (if correctly diagnosed as ATC) they would not have survived for two years if the ATC was still present. In such rare cases, the patient now needs to have their papillary or follicular cancers (that had been clinically ignored) independently dealt with, using I-131 scans and therapy. In some particular circumstances, this may be done after only a year, especially if the thyroglobulin is significantly increasing despite suppression of TSH with levothyroxine.
2) Typically, ATC does not make thyroglobulin (or very little, if any). If there is ATC present, the thyroglobulin actually represents the co-existing papillary or follicular thyroid cancer and does not reflect the presence or absence of ATC tumor. We tend to ignore the thyroglobulin level until we are confident that the ATC has been dealt with and it is time to deal with the underlying papillary or follicular cancer.
3) Appropriate treatment of ATC requires an excellent surgeon to do as complete a removal of the thyroid tumor and as much of the thyroid gland as is possible. Following this surgery, it is VERY necessary to undergo a full course of external beam radiotherapy (XRT), often using a hyper-fractionated approach. At this time it is important to do a complete “tumor staging”. This consists of CT scans of all major areas of the body (contrast SHOULD be used in the context of ATC). This is for the purpose of searching for any evidence of tumor sites in the body. It is exceedingly rare for anyone with ATC to avoid having such tumor show up. These CT scans should be repeated every 3 weeks for the first 3 months, then monthly thereafter (until tumor sites are found or two years pass; the second year, the CT scan interval can be every two months).
4) When these CT scans document evaluable sites of ATC tumors (usually in the lung or liver), then it is time to undertake chemotherapy. There are no chemotherapy drugs with excellent and reproducible activity against ATC cells. Of all of the available standard drugs, taxanes (paclitaxel (taxol) and taxotere) have the greatest activity, but it is not for sure in any particular patient. None of these drugs can be given without significant potential side effects and it is unreasonable to take them unless they demonstrate their effectiveness in the patient. For that reason, it is important to avoid giving them unless there are clear and objective clinical endpoints. That is why my best advice is to wait until there is objective evidence (for example CT scans showing new lung nodules) so that the benefit of these drugs can be verified by seeing the nodules shrink or disappear. In the absence of such objective clinical endpoints, a significant number of patients would get toxic effects of therapy without benefit and with no idea of when to stop the treatment. Considering the consequences of toxicities from ineffective chemotherapy drugs, it's better to wait than to "spin your wheels in the mud."
5) Alternatively, there are occasionally clinical trials for ATC; however, most such trials still require the presence of "evaluable" disease before starting their experimental agent. It is critical to enlist the assistance of an oncologist to search the National Cancer Institute PDQ Database to see if there are any reasonable clinical trials that might be appropriate.
6) Every week or so, I receive phone calls from physicians around the globe to discuss their patient with ATC and ask for suggestions and education regarding treatment options. Although I do not typically see such patients in my own practice, it is a very reasonable opportunity to have your physician(s) contact me at 800-888-5533 (PHYSICIANS ONLY) to discuss the situation.
7) The final message is that "time is clearly of the essence." Waiting (sometimes even by a week or more) can limit the treatment options and alter the outcome. You should use your primary care physician to call specialists directly. Scheduling clerks and nurses generally have absolutely no inkling of the urgency of this matter. Any medical or surgical referral should evolve through a direct telephone call from your physician to the consultant so that the issues are clearly understood and so that there is as little delay as humanly possible.
—ThyroidCancerHelp, February, 2008
Antiangiogenesis in thyroid cancer
Antiangiogenic therapy is indeed a viable direction to treat rapidly proliferative non-iodine-avid thyroid cancers. My laboratory has been pursuing this direction for several years. We've just published a reasonably successful clinical trial using thalidomide
for this purpose: Ain KB, Lee C, Williams KD 2007 Phase II Trial of Thalidomide for Therapy of Radioiodine-Unresponsive and Rapidly Progressive Thyroid Carcinomas. Thyroid 17:663-670.
In addition, we've been very impressed with the results, so far, in our ongoing clinical trial using lenalidomide (Revlimid; a derivative of thalidomide). The "answer" to this clinical problem will likely eventually involve multiple new medications.
—ThyroidCancerHelp, September, 2007
Anti-angiogenesis, research into
It is most unfortunate that sometimes thyroid cancer spreads to parts of the body that make them particularly dangerous and difficult to treat. It is also very true that thyroid cancers tend to be highly vascular, that means that they induce the body to provide many blood vessels to feed such tumors. This can make surgery very difficult and dangerous, particularly when the tumor involves bones or regions in the spinal cord or brain.
My laboratory has been involved in research in this area for nearly a decade, trying to find drugs that will block the formation of feeding blood vessels to these tumors and cause the tumors to stop growing. Our studies have been reasonably successful, resulting in a successful clinical trial using thalidomide as an antiangiogenesis (against the growth of new blood vessels) drug to keep metastatic thyroid cancers from growing (Ain KB, Lee C, Williams KD 2007 Phase II trial of thalidomide for therapy of radioiodine-unresponsive and rapidly progressive thyroid carcinomas. Thyroid 17:663-670.). Although promising, thalidomide was not the best drug considering its side effects.
We systematically tested other agents, particularly new drugs that had been chemically modified from thalidomide, using human thyroid cancer tumors grown in nude mice in our laboratory (these mice are genetically altered so that their immune systems do not reject the human cells). We found that lenalidomide (Revlimid) was particularly effective and have been conducting a phase 2 clinical trail with this drug for nearly two years. The preliminary results will be reported at an oncology meeting in late May, but are excellent enough to warrant additional clinical trials in the near future. Unfortunately, it seems that thyroid cancer metastases at different body sites respond differently, with the most responsive tumors being in the lungs or liver.
Antiangiogenesis drugs have not yet been used pre-operatively to permit the surgery to be performed easier, partly because they do not destroy existing blood vessels, but rather keep tumors from recruiting new blood vessels. Because of this, we frequently have the radiologist thread a tube into the blood vessels that feed some of these tumor sites and try to block the blood vessels by injecting special substances, a process called embolization. There is another class of experimental drugs called "tumor vascular-targeting agents" that are intended to destroy existing blood vessels feeding tumors. Unfortunately, there is not yet sufficient effectiveness of this drug approach.
Research efforts continue at my lab and at other labs. We are all working hard to increase the number and effectiveness of our treatment options. For some patients, the answers will not come soon enough.
—ThyroidCancerHelp, January, 2008
Anti-thyroglobulin antibodies (a primer on)
Around 20% of thyroid cancer patients have auto-antibodies against their own thyroglobulin. These antibodies tend to interfere with the accurate measurement of thyroglobulin. The typical medical condition associated with anti-thyroglobulin antibodies is called Hashimoto's thyroiditis.
Hashimoto's thyroiditis is very common, afflicting nearly 20% of women and 10% of men. For that reason, it is very common to have coincidental thyroid carcinoma and Hashimoto's thyroiditis. One of the hallmarks of Hashimoto's thyroiditis is the production of antibodies directed against parts of the thyroid, particularly the thyroperoxidase enzyme and thyroglobulin.
Antibodies against thyroglobulin interfere with the ability of all currently known blood tests to accurately measure the actual thyroglobulin level. They tend to make the tests register a lower thyroglobulin level than actually exists. As you know, thyroglobulin levels are extremely important to ascertain the presence of thyroid cancer after a person has had a total thyroidectomy and radioactive iodine therapy. For this reason, a low or immeasurable thyroglobulin level, in the presence of anti-thyroglobulin antibodies, does not provide any confidence for the absence of thyroid cancer. On the other hand, when thyroglobulin levels are elevated in the presence of anti-thyroglobulin antibodies, particularly when these levels increase in response to hypothyroidism, this is believable evidence of the presence of thyroid cancer.
The body's immune system is carefully programmed to produce antibodies against foreign invaders, such as bacteria, viruses, and toxins. When vaccines are given to people, they consist of inactive samples of the virus or toxin that are injected to produce an antibody response from the white blood cells. These vaccine-stimulated antibodies protect the person against that specific virus or toxin. The white blood cells retain a memory regarding the production of this particular antibody, the "amnestic response," which permits them to rapidly make antibodies whenever the virus enters that person. Unfortunately, when the white blood cells endure a long period of time without seeing that particular virus, they "forget" how to make that specific antibody. That is the reason why booster shots are given to restore the vaccine's protection [for example, the tetanus vaccine].
If you understand this, you could see how a thyroid cancer cell, making thyroglobulin, can function as producing "booster shots", enhancing anti-thyroglobulin antibody production in patients with Hashimoto's thyroiditis and thyroid cancer. For those patients who are truly free of this thyroid cancer, the absence of these "booster shots" permits the memory of the white blood cells making this antibody to fade and the antibody go away.
This is the reason how we can use the persistence of anti-thyroglobulin antibodies to suggest the persistence of thyroid cancer, and the loss of these antibodies to suggest the absence of remaining thyroid cancer. Likewise, should these anti-thyroglobulin antibodies suddenly appear (provided that this is not due to lab error) it is likely to signify a proliferation of persistent thyroid cancer cells.
—ThyroidCancerHelp, September, 2007
Anti-thyroglobulin antibodies (persistence of)
The presence of measurable thyroglobulin in the blood, for people who have had their thyroid glands and thyroid cancers removed surgically and have had the remains of those items properly destroyed with radioactive iodine, indicates persistent/recurrent thyroid cancer. Unfortunately, nearly one quarter of thyroid cancer patients produce antibodies against their own thyroglobulin that interferes with all laboratory tests seeking to measure the thyroglobulin level. Most of the time, these antibodies cause the thyroglobulin level to appear lower than it actually is.
Over time (several years), if all thyroid cancer has been effectively eliminated, consequent to successful treatments and good fortune, the level of anti-thyroglobulin antibodies will diminish and disappear as the "memory" B-lymphocytes start to "forget" their blueprint for making anti-thyroglobulin antibodies. The loss of those antibodies, with zero thyroglobulin levels, is very reassuring that there is no evidence of persistent thyroid cancer. Likewise, the persistence of these antibodies, is suggestive of persistent disease (although it may take 2 to 4 years for the antibodies to disappear in the absence of disease).
—ThyroidCancerHelp, July, 2007
Armour thyroid extract: do not use
Thyroid cancer patients should not be on desiccated thyroid extract (Armour thyroid). Permit me to quote one of my earlier postings from long ago:
Levothyroxine (T4) is the major product of the thyroid gland and is essentially a prohormone with minimal (if, debatedly, any) activity of its own. It has a long and stable half-life in the blood (one week) and is transported into cells where it is converted into T3, which directly interacts with receptors which bind DNA and regulate genes. All of this has been well-studied and constitutes a vast medical and molecular biology literature. For patients without thyroid glands, the ingestion of a pure levothyroxine product provides ALL of the necessary thyroid hormone products consequent to normal metabolic and enzymatic bodily processes.
There is absolutely no conceivable role for taking Armour thyroid extract or mixtures of T3 and T4. Most of my colleagues and I would be happy if the FDA removed these items from production. Thyroid extract is a mixture of T4, T3, thyroglobulin, and many other breakdown products with erratic pharmacokinetics and nearly impossible to accurately titrate for suppression of TSH. There is no magical or supernatural or any advantage to this animal product. Armour thyroid provides a mixture of hormones that are produced in pigs, not in humans. The only reasonable medication is pure levothyroxine (choose your brand). Cytomel is useful for the first four weeks of the six-week levothyroxine withdrawal period in preparation of I-131 scans and or therapy. It also has very limited utility for supplemental treatment of myxedema coma unresponsive to levothyroxine. (A medical study from a couple of years ago suggesting T3 supplementation of levothyroxine therapy for hypothyroidism is not generally accepted by thyroidologists, for many good reasons, and has been debunked in multiple follow-up clinical trials.)
There is nothing gained by choosing medications based on "natural" extracts or processes. Such items, frequently found in "Health Food" stores, are often dangerous, impure, untested, and of unproven value. Their designation as a "natural" product merely protects their manufacturers from having to justify their purity, safety, and efficacy to the FDA (which is empowered to protect us from "pharmaceuticals" only), permitting great financial profits at the expense of the public. Many new drugs, such as Taxol (from the Yew tree), and old drugs, such as penicillin (from mold), come from sources in nature. In comparison to "Health Food" shenanigans, these natural products are stringently purified and tested prior to making them available as medications. It is possible that a few of the "natural" products may have a fraction of a percent of a useful agent, mixed in with far larger quantities of toxic and useless "natural" chemicals. Next time you go to these unregulated "Health Food" stores, consider that the poison on the darts used by various native peoples did not come from a drug store. Finally, in the wake of experience with "mad cow" disease in England and the known presence of prion diseases in cows, sheep, humans, and other mammals, anyone who would knowingly take an animal product over a chemically pure synthesized compound should have their head examined (for spongiform encephalopathy).
—ThyroidCancerHelp, July, 2007
B
Barium and iodine
Swallowed barium will not interfere with radioactive iodine scans or therapies. On the other hand, sometimes radiologists use an oral contrast agent that contains stable iodine and WILL interfere. Make certain that "barium" truly is barium.
—ThyroidCancerHelp, July, 2007
BRAF mutations in papillary thyroid cancer
The recent discoveries regarding BRAF gene mutations have to do with a protein in cells that controls certain biochemical pathways related to cell growth and behavior. A portion of patients with papillary thyroid cancer have a mutation of this gene that causes its regulatory pathway to be excessively "turned on" possibly accounting for more aggressive tumor behavior. These are just a few of many discoveries regarding various tyrosine kinase pathways that are likely to be exploited in future new therapies. Aside from analyzing for such mutations in needle biopsies of thyroid nodules (something that may be done in the future) or looking for these mutations in resected tumors for prognostic information, analyses for such mutations do not yet have any direct clinical application.
—ThyroidCancerHelp, January, 2008
Breast feeding and thyroid cancer
In a person that is free of any evidence of persistent thyroid cancer (clean I-131 whole body scans with no measurable thyroglobulin, as well as clean chest CT scans and clean neck ultrasounds) and is not planning to have radioactive iodine scanning for at least a year or more, breast feeding is fine and of no ill consequence to the child or to the mother. On the other hand, lactating women should not undergo radioactive iodine scans or therapy until their child has been completely weaned and the breasts have had sufficient time to completely "dry up."
—ThyroidCancerHelp, June, 2007
Biopsies (don't ask too much from)
Fine needle biopsies of thyroid nodules are not capable, nor intended, to do much more than determine whether there is a reasonable likelihood that a nodule is malignant. To demand more details than that is similar to demanding that the cover of a book reveal everything that is written inside.
Sometimes a biopsy is able to reveal that a tumor is an anaplastic cancer, a medullary cancer, or a thyroid lymphoma. In such circumstances, knowing that it is anaplastic can prompt a careful evaluation for disease extent prior to the surgery to permit proper treatment planning. Likewise, knowing that it is a medullary thyroid cancer can prepare the surgeon to do a very complete bilateral neck dissection, necessary for the best chances for treatment. If it is a lymphoma, the surgery can be avoided and the treatment would be very effective using just external beam radiotherapy and chemotherapy. For most other thyroid cancers, papillary and follicular and the respective variants, merely knowing that the nodule is an adenocarcinoma is fully sufficient and dictates the need to remove the thyroid gland surgically.
It is important to avoid demanding more information from a procedure, than the procedure is able to provide, particularly if such information is of no additional benefit.
—ThyroidCancerHelp, August, 2007
Biopsies—thyroid surgery
A biopsy of a thyroid nodule is a wonderful tool, but imperfect and limited. It's inappropriate to ask more of this technique than it is equipped to deliver. There are only three reasonable outcomes of a thyroid biopsy that has been properly performed and contains sufficient numbers of cells to evaluate: clearly benign, clearly malignant, and indeterminant/suspicious. Only patients with those nodules that are clearly benign by biopsy should avoid having thyroid surgery.
—ThyroidCancerHelp, September, 2007
Bone metastases from misdiagnosed thyroid cancers
There is a classic type of thyroid cancer mismanagement that is much too often repeated. It starts with the misdiagnosis of a follicular thyroid carcinoma as a benign follicular adenoma. Many years later, the follicular carcinoma, that had already been metastatic to distant sites in the body before the surgery, grows large enough to be discovered. Sometimes it is discovered as a tumor growing on a rib or in the spine. Sometimes it is found as a tumor growing in the brain or in the lung. Once this metastatic tumor is found and biopsied, revealing itself to be a thyroid cancer, the proper steps are crystal clear. Unfortunately, it seems that such clarity is not apparent to some physicians.
There is NO ROLE for any further thyroid scans on the remaining thyroid lobe. It needs to come out ASAP, regardless of whether it harbors additional cancer or is completely normal thyroid tissue. This is because it is impossible to effectively administer radioactive iodine for therapy or scans if it is left in place. Next, if there is a tumor on bone, it should be surgically removed. This is necessary, even if it is fairly extensive, if at all possible. Likewise, large tumor masses in the lungs (if localized to a small portion of one lung) or tumor masses of any size in the brain should be removed or subjected to stereotactic radiosurgery ("gamma knife"). External beam radiation for bone metastases, instead of surgery, is usually inappropriate.
Once there is surgical clearance of macroscopic disease, the stage is set for radioactive iodine therapy (ideally, high dose therapy utilizing dosimetry). Knowing this in advance, the wise physician will assiduously avoid any use of CT contrast dye. Instead, MRI scans with gadolinium can be equally effective without interfering with I-131 treatment. I could, and have, write entire chapters on the management of this problem. Very, very sadly, as in the case above, the treating physicians have no inkling of the appropriate course.
—ThyroidCancerHelp, August, 2007
C
Calcitriol is preferred over Zemplar
There is no reason that I can imagine for someone with hypoparathyroidism to be treated with Zemplar (paricalcitol). It has the same mechanism of action as calcitriol and is just as useful, but far more expensive. The retail price (in Kentucky) for 30 pills of 1 mcg Zemplar is $235.00. The retail price for 30 pills of 0.5 mcg calcitriol (equivalent to 2 mcg Zemplar) is $60.00. There is no reason to pay more than four times as much for no added benefit. The appropriate dosing interval of both Zemplar and calcitriol is once per day.
Many people with hypoparathyroidism have only a partial parathyroid hormone deficiency, requiring less calcitriol and calcium than someone with complete deficiency. When the vitamin D analog (calcitriol) dosage is excessive, less calcium is needed; however, this is usually at the expense of an excessive phosphate level. The best ratio is to use the least dose of calcitriol and sufficient calcium (taken three to four times daily) to keep the IONIZED calcium in the low normal range.
—ThyroidCancerHelp, October, 2007
"Capsules" in thyroid cancer pathology reports: A primer
To avoid current and future confusion, I'll briefly discuss the issue of "capsules" as it pertains to thyroid cancer pathology.
Capsulation refers to the fibrous (collagenous) tissue that encircles and encloses a structure. There are two, very different, types of capsules when discussing thyroid cancer pathology: tumor capsule (covering the thyroid tumor inside the thyroid) and thyroid capsule (covering the entire thyroid gland).
Some thyroid tumors are covered by a "capsule" of fibrous tissue. In the case of FOLLICULAR thyroid tumors, it is important to note whether any of the tumor cells have penetrated into and through this tumor capsule. If there is even a single area of tumor capsule invasion OR a single area in which the tumor cells have invaded into a vein or artery (vascular invasion), then the tumor is known as a FOLLICULAR CARCINOMA. If not (requiring the ENTIRE tumor to be carefully examined) it is called a FOLLICULAR ADENOMA. This is also the way that Hurthle cell neoplasms are characterized: even a single instance of capsular or vascular invasion distinguishes a Hurthle cell carcinoma from a Hurthle cell adenoma. This is a very tedious and meticulous assessment, if done properly. PAPILLARY CARCINOMAS are NOT distinguished as being cancers based on tumor capsular invasion and the presence or absence of a tumor capsule merely adds to the description of the papillary cancer.
On the other hand, the THYROID CAPSULE is often not much of a definitive capsule, often comprised of a very thin layer of fibrous tissue, but it can be very important in discerning behavior of thyroid cancers. Thyroid cancers of any type (papillary, follicular, medullary, etc.) that "eat their way" through the thyroid capsule are frequently found to be particularly aggressive. If there is extensive thyroid capsular invasion, particularly if the tumor also invades surrounding muscle or vital structures (esophagus, trachea, nerves, etc.) then there is a higher risk of distant spread of the tumor (lung, bones, liver, brain, etc.).
Thus, sometimes the assessment of invasion of the tumor capsule can add to the diagnostic classification of the tumor, whereas the assessment of thyroid capsular invasion provides important prognostic information.
If a thyroid tumor is described as non-encapsulated, it merely means that this particular tumor has no evidence of a fibrous capsule. It is very different from a description of having a capsule that has been invaded. Do not confuse these issues.
ALL of the variants of papillary thyroid cancer are dealt with in the same fashion in regards to the tumor capsule. The presence of absence of a tumor capsule is merely descriptive for all of the papillary variants, since the diagnosis of malignancy for such cancers is based on the appearance of the cell nucleus, not on whether there is invasion of the tumor capsule. Also, there is NO difference in the prognostic risk between encapsulated and non-encapsulated follicular variants of papillary thyroid cancer. The determinants of risk are related to the size of the tumor (bigger is worse), the extent of nodal metastases (more is worse), and the presence of invasion through the THYROID capsule into surrounding tissues (such invasion is worse).
—ThyroidCancerHelp, November, 2007
CT contrast dye and radioactive iodine
It is completely inappropriate to use CT contrast dye in any person planned for radioactive iodine scanning or therapy within 8 months. The stable (non-radioactive) iodine from the CT dye can persist within a person for 2 to 12 months and it is totally unpredictable how long it will take to clear in any particular individual. To find out if one has cleared the stable iodine from a preceding contrast dye exposure, you should follow a strict low iodine diet for one week and collect a complete 24 hour urine for the last day of that week, having this analyzed for urine iodine (by the Mayo Clinic Laboratory in Rochester, MN). Optimal 24 hour urine iodine values total 50 micrograms for the entire 24 hour sample; however values under 100 mcg are sufficient.
There is NO NEED for contrast dye for a CT scan of the chest, unless the physician is specifically looking within the mediastinum (the area around the heart). If contrast dye is necessary for a body area (such as the liver) then an MRI is better, since MRI dye (gadolinium) does not contain stable iodine.
It's quite sad to compromise the effectiveness of a treatment regimen with radioactive iodine, merely to take a picture with a CT scan. On the other hand, if a person is adequately prepared for this radioactive iodine scan (elevated TSH and low iodine diet) and has a negative study despite an elevated thyroglobulin, it is very likely that the tumor is unable to concentrate iodine and this particular modality should be abandoned.
—ThyroidCancerHelp, June, 2007
CT contrast dye exposure before thyroid surgery
Physicians are often well-intentioned in their efforts to "help" patients, but unfortunately their efforts end up counterproductive. Ultrasounds permit assessment of nodules without contrast and biopsies are the only way, short of surgery, to appropriately assess thyroid nodules. If CT contrast dye has been used and thyroid cancer (necessitating radioactive iodine therapy) is later discovered, then it's a matter of weighing a delay in I-131 treatment until the urine iodide levels are low enough or proceeding ahead. The only way to make such choices is to consider the findings at the time of surgery. Until that time, all speculation is useless.
—ThyroidCancerHelp, October, 2007
CT contrast dye (oral vs. intravenous)
I have evaluated patients after oral (likely the same as rectal) iodinated contrast material, as well as those who have received betadine skin preparations during their surgery. The data shows that these sources of stable iodine are handled much like dietary iodine and are cleared by two weeks. On the other hand, intravenous stable iodine from contrast dye can remain for many months.
—ThyroidCancerHelp, September, 2007
CT contrast dye, PET scans, and I-131
CT scan contrast dye can interfere with radioactive iodine uptake for 2 to 10 months. The only way to verify that sufficient time has passed to eliminate such interference is by following a low iodine diet for one week and obtaining a 24-hour urine iodide measurement (done by the Mayo Clinic labs) on the last day of the diet. A total urine iodide level of less than 100 mcg shows that the interference has passed.
18-FDG, used for a PET scan, will not interfere with I-131; however, any iodinated contrast used for the CT fusion component certainly will. Oral contrast will interfere for only 2 weeks; but IV contrast will interfere for 2-10 months.
—ThyroidCancerHelp, September, 2007
CT scan contrast dye and radioactive iodine use
Here is the simple information on this:
Even a single use of iodinated CT contrast dye (and ALL intravenous CT contrast dye IS iodinated, without ANY exception) can cause non-radioactive (stable) iodine to persist in the blood in sufficient amounts to interfere with radioactive iodine scans or therapies for 2 to 12 months. If such dye has been used, inadvertently or unavoidably, we can determine when it has passed out of the system by measuring the iodine in a 24-hour urine sample while in the final day of a one-week low iodine diet.
CT scans of most parts of the body (with the exception of the chest) usually require contrast dye for optimum sensitivity. CT scans of the chest DO NOT need such dye because it is easy to evaluate the lungs for nodules (air-solid interface) without such contrast dye. For other body parts, MRI scans are perfectly fine and can freely use gadolinium contrast dye without any interference problem. Alternatively, ultrasounds are likewise useful for selected body areas.
On the other hand, should there be a medical emergency, such as the need to do a cardiac catheterization (using iodinated contrast dye) to avoid an impending heart attack or the need to find the sources of bleeding with a contrast CT scan after a motor vehicle accident, common sense suggests that the issue of radioiodine interference is secondary in consideration.
—ThyroidCancerHelp, June, 2007
CT scan dye contains IODINE
ALL CT scan contrast dye contains massive amounts of stable (non-radioactive iodine). A CT scan contrast dye without iodine has never been seen on this planet yet. A single dose of this contrast dye has the potential to interfere with all radioactive iodine scans and therapies, regardless of whether hypothyroid or Thyrogen preparation is used, for 2 to 10 months.
Unless it is an emergency, such as chest pain evaluation with a cardiac catheterization or an automobile accident needing a CT scan with contrast to evaluate internal bleeding, there is no need for contrast dye to be used if radioiodine is to be used within the critical interval. Necks can be evaluated with ultrasound or MRI (gadolinium contrast is OK). Chest CT scans do not need contrast to be informative. Abdomen and pelvis studies can be done with MRI. There is no excuse to senselessly waste exposure to radioactive iodine and compromise clinical care for optional diagnostic CT scans.
—ThyroidCancerHelp, September, 2007
Cytomel and levothyroxine combined for chronic therapy: DO NOT USE
I DO NOT advise taking levothyroxine and Cytomel (liothyronine) together in combination as chronic therapy. This is very ill-advised for any thyroid cancer patient. In addition, many well done studies have proven it to be of no advantage for hypothyroid patients.
The ONLY valid use of Cytomel in any foreseeable clinical situation is for the hypothyroid preparation for radioiodine scanning and therapy or for the transition from a hypothyroid state back to being on thyroid hormone.
—ThyroidCancerHelp, August, 2007
Cytomel doses (don’t make up missed)
Unlike levothyroxine, that has a long half-life of a week, Cytomel has a very brief half-life. For that reason, you should not "make up" missed doses of Cytomel.
—ThyroidCancerHelp, September, 2007
Cytomel is well tolerated
It is exceedingly rare that a patient cannot tolerate Cytomel as part of the levothyroxine withdrawal preparation for radioiodine scanning or therapy. Usually, the problem is that they are being given the wrong dosage of Cytomel. Although most people feel fine on 25 mcg twice daily, this may be too much for some people. In such cases, I have them split the tablet, making the dose 12.5 mcg, and take the pill three times daily (or more rarely, twice daily). This is taken for 4 weeks after thyroid surgery or stopping levothyroxine; then the Cytomel is stopped for 2 weeks (while on the Low Iodine Diet) prior to receiving I-131 for scanning or therapy or both.
Although it is possible that less time than 6 weeks from stopping levothyroxine (or thyroid surgery) is adequate to get the TSH higher than 30, this is VERY variable between people. In my very busy practice, it's not possible to schedule people months in advance with variable and uncertain lengths of preparation. Cytomel (used as described above) is useful for my scheduling, for nuclear medicine scheduling, for patients to work out with their employer, and to clearly define the time that driving and working will not be possible. It is very rare for this 6 week preparation to fail to elevate the TSH appropriately and my patients find it easier to have a limited period of hypothyroidism, rather than a drawn out period that is far longer without Cytomel.
I delayed answering the question regarding the article in Clinical Endocrinology (Vol 67, p839, 2007) by Leboeuf et al, until I had a chance to read it. I find it totally unconvincing and poorly done. In this study, the authors used an outdated psychological assessment scale (the Billewicz score) and seemed to show that patients on Cytomel with normal TSH levels were equally "hypothyroid" as patients off of all thyroid hormones with TSH values as high as 60. Unfortunately, their findings do not jibe with clinical experience and seem to be an artifact of using an inappropriate and insensitive assessment test. It's very important to assess the medical literature critically by carefully reading the entire paper, not just the brief abstract.
—ThyroidCancerHelp, December, 2007
Cytomel (liothyronine) is not appropriate chronic thyroid hormone therapy
Cytomel (liothyronine) is NOT appropriate chronic thyroid hormone replacement therapy. It's primary role is as a temporary thyroid hormone treatment during the early phase of levothyroxine withdrawal for radioiodine scans or therapy. It has such a brief lifespan in the blood, that your body is exposed to a roller-coaster of too much to too little hormone throughout the day and night. It is far more likely to evoke thyrotoxic problems and is not useful for the long-term suppression of the TSH level that is the hallmark of thyroid cancer management.
—ThyroidCancerHelp, June, 2007
D
Dr. Ain (direct help from)
I am happy to provide education and advice regarding any thyroid cancer (particularly anaplastic thyroid cancer), provided that the physician takes the initiative to call me directly, via my PHYSICIANS-ONLY paging service at 800-888-5533.
It is not possible for patients or their families to directly make appointments to see me. My practice has been closed to new patients for over a year. The only exceptions have been patients whose surgery has been performed by our surgeons at the University of Kentucky, patients entering my experimental clinical trials (referred via their physicians) or special
situations that are discussed with the physician. I am hopeful that I can re-open my practice in the future after I have been successful recruiting another physician to join me. At this time, the straw has nearly broken the camel's back.
—ThyroidCancerHelp, September, 2007
Dosimetry (an explanation of)
The most commonly used type of radioactive iodine dosimetry is a method for determining the maximal dose of radioactive iodine that can be administered to a particular person at a particular time that has a reasonable likelihood of being safe for that person (in terms of toxicity).
It involves preparing a person with a hypothyroid withdrawal and low iodine diet, then administering a small tracer dose of radioactive iodine (I-131) to swallow. Blood samples are obtained at specific intervals over 5 days and whole body radiation counts are obtained at the same intervals. Data obtained by measuring the radioactivity of the blood samples and body counts are entered into specific computations to model the radiation dose to the bone marrow and lungs, making sure that safe limits are defined. These calculations define a "safe" upper limit for the treatment dose.
The choice of whether to administer the maximal I-131 dose defined by the dosimetry study is a clinical decision of the physician based upon the nature and extent of the thyroid cancer being treated. Some times a lower dose is administered if the physician feels that a maximal dose is not necessary or safe for some reason. Sometimes the dosimetry study reveals that a dose that the physician was planning to give would be too high for safety in a particular patient. Thus the dosimetry calculation can sometimes make the physician choose an administered dose lower than previously intended.
The determination of what a patient should be given for a particular thyroid cancer treatment need remains an individual decision of the physician and is strongly influenced by the training and experience (or lack thereof) of that particular physician. Even among physicians who are considered "experts" in the field, the choice of treatment dose can differ by more than 10-fold for any particular circumstance. This is unfortunate and confusing for patients; however, I do not foresee any likelihood of a consensus regarding this that is based on valid principles. The best suggestion is to carefully choose your physician.
—ThyroidCancerHelp, October, 2007
E
Elevated thyroglobulin=persistent tumor
The presence of measurable thyroglobulin levels, even as low as 2, indicates the presence of persistent thyroid cancer.
There are FOUR common errors made in the followup of thyroid cancer: 1) permitting measurable thyroglobulin to be present without fully searching for the tumor source; 2) presuming that any persistent thyroid cancer MUST be in the neck despite the fact that it can spread to anywhere in the body; 3) presuming that thyroid cancer ALWAYS takes up radioactive iodine. (Sometimes, unfortunately, it loses this ability and will not respond to radioactive iodine for either therapy or scans. Sometimes it is "invisible" to the tracer dose of radioiodine, but able to be "seen" or treated with a larger treatment-level dose); and 4) placing any reliance in the assertions of any surgeon that he/she "got it all." (It requires a mass of at least 2,000,000 thyroid cancer cells in a lump for a surgeon to be able to see it and remove it during surgery. All thyroid cancer tumor masses of 1,000,000, 100,000,10,000, etc. etc. are too small to be seen by any human (or bionic) surgeon.)
As long as interference from non-radioactive iodine is ruled out, the presence of thyroglobulin in the blood should instigate a full assessment of the entire body using a variety of radiological techniques and sometimes using PET scans. Frequently, even after such efforts, the site of the persistent thyroid cancer remains undiscovered. In such situations, maintaining excellent suppression of the TSH with levothyroxine (keep TSH < 0.1) and maintaining a reasonable schedule (avoid bankruptcy or spending all your life in the CT scanner) of continued studies to search for this tumor is the best course with our current state of knowledge.
—ThyroidCancerHelp, June, 2007
External beam radiation (coping with)
External beam radiotherapy to the neck is no picnic. I tell my patients that it is a difficult mountain to climb, but at some point they'll reach the top, have an easier descent, and then reach level ground. It's VERY important to keep well hydrated, maintain nutrition, medications, and appropriate analgesia for a very painful sore throat. The course of radiation is typically given over a month. Each month following, there is considerable improvement in symptoms. For roughly two thirds of my patients, there is very little left of any side effects one year later. For the rest, there may be thickening of the neck tissues (that improves with stretching exercises), prolonged neck tenderness, or sometimes unusual sensations when rapidly bending the neck.
The key purpose of the radiation therapy is prevent disease progression and spread: a much more dangerous consequence than the effects of the radiation. It's very important to maintain communication with the radiation therapist and make use of his/her expertise in preventing or relieving side effects.
—ThyroidCancerHelp, December, 2007
External beam radiation vs. I-131 therapy
For differentiated epithelial thyroid cancers (papillary, follicular, and their variants), external beam radiotherapy is not typically advised unless there has been definitive previous demonstration of loss of radioiodine uptake in that particular person. Sometimes, when the surgeon notes a greater extent of residual disease than indicated by diagnostic radioiodine scanning (particularly when the thyroglobulin is discordantly elevated), a course of external beam radiation could follow the radioiodine therapy; however, it should not precede radioiodine therapy because it is likely to imperil the effects of radioactive iodine.
For tumor tissues that concentrate and retain radioactive iodine very well, an appropriately-dosed radioactive iodine treatment can impart >300 Gray of radiation per gram of tumor; however, the best that external beam radiation can do is little more than 60 Gray per gram.
—ThyroidCancerHelp, September, 2007
External beam radiotherapy for recurrent iodine non-avid local disease
When there is definitive macroscopic tumor recurrence in the neck that is definitely not able to concentrate radioactive iodine, it is best removed with surgery. As soon as there is sufficient wound healing, it is my practice to proceed with external beam radiotherapy (XRT). This is based upon the following factors: 1) XRT works best on microscopic tumor, rather than macroscopic tumor; 2) the surgeon is intrinsically unable to remove microscopic residual disease during the surgery and this is almost certainly still there; 3) should sufficient time elapse for the thyroglobulin levels to again rise, it is quite possible that there would be recurrent macroscopic disease that would require ANOTHER surgery prior to effective XRT (the situation would entirely recur again); and 4) if successful XRT is completed and later on the thyroglobulin increases, attention would be able to be focused upon other distant sites of potential tumor metastases.
Many physicians have very different ideas and approaches to this situation. Some are very meek about using XRT and need to be forced into it by rising thyroglobulin levels. I don't share such issues because I have a significant amount of experience with the successful application of this approach. Of course, in life and in medicine, there are no guarantees.
—ThyroidCancerHelp, August, 2007
F
Focal invasion vs. diffuse invasion
In its application to pathology, "focally" means that something occurs at a distinct and particular spot. This is the opposite of "diffusely", meaning that it occurs in a dispersed or widespread location. When this is applied to the assessment of thyroid capsular invasion, it refers to the tumor having grown through the fibrous layer that overlies the thyroid gland. This shows early invasive tendencies of the tumor and is a feature suggesting aggressiveness. Of course, if the tumor is diffusely invasive, this is a much worse situation.
—ThyroidCancerHelp, October, 2007
Follicular variant papillary thyroid cancers
Papillary thyroid cancers comprise a variety of subtypes, among them: follicular variant papillary thyroid cancer. This variant of papillary cancer shows a follicular pattern under the microscope, but has special features seen in the nucleus of the cancer cells that properly classifies it as a papillary thyroid cancer. Before 20 years ago, many of these types of thyroid cancer were incorrectly classified as follicular thyroid cancers. They behave the same as typical papillary thyroid cancers and the follicular appearance does not, by itself, suggest it to be any more aggressive.
Of course, those people with larger thyroid cancers, invasion of blood vessels, and spread to lymph nodes have a situation that suggests a greater risk for recurrence or spread of the tumor or of resistance to treatment. Nonetheless, just having those features does not mean that there will be difficulty in responding to therapy or that the treatment won't work. It means that nothing should be taken for granted and that there should be careful follow-up and verification of response, each step of the way. No one is ever "cured" of their thyroid cancer. Instead, we want to keep monitoring and evaluating each patient on a regular basis until they die of old age (a preferred endpoint). Since many of my patients are much younger than me, I tell them that I'll take care of them until one of us dies of old age (and they'll likely have to switch horses later in the race).
Interference with radioactive iodine therapy from non-radioactive (stable) iodine from CT scan contrast dye can occur if the dye had been given BEFORE the radioactive iodine, NOT after the radioactive iodine. However, the effects of this dye upon subsequent radioactive iodine scans or therapy may persist for 2 to 12 months.
—ThyroidCancerHelp, July, 2007
G
Graves' disease and thyroid cancer
The stimulation of thyroid tissue or involvement of eye muscle tissue that is seen in Graves' disease is consequent to auto-antibodies. The suppression of TSH used for treating thyroid cancer should not exacerbate the eye disease. On the other hand, since Graves' disease auto-antibodies can act on the TSH receptors, working just like TSH does, it is likely that suppressing TSH with thyroid hormone will not be quite as effective. This is because Graves' disease antibodies function just like TSH and they cannot be suppressed by thyroid hormone.
—ThyroidCancerHelp, September, 2007
H
Hair loss in female thyroid cancer patients (causes)
Although men have the advantage in regards to hair loss, because it is far more common for them and reasonably socially acceptable, it is clearly not appreciated or acceptable for women. Sometimes hair loss in women is due to autoimmune disease that targets the hair follicles. Sometimes, hair loss is caused by situations in which androgenic hormones are elevated, such as in polycystic ovary syndrome. Sometimes hair loss is "idiopathic", which simply means that we don't know why.
Thyroid hormone can transiently affect the hair, particularly when it is precipitously changed, such as during hypothyroid preparation for radioiodine therapy or scans. In that case, usually any hair that is lost is regrown and there isn't a net loss of hair. Merely being on higher than normal doses of levothyroxine, to suppress TSH and keep thyroid cancers from growing, does not alter the amount of hair on the head. If there is persistent thyroid cancer in the lung, unresponsive to radioactive iodine yet kept from growing because of the suppressive levels of levothyroxine, it would be terrible to decrease the levothyroxine and have no benefit in terms of preventing hair loss.
There are some women who need to be on a beta blocker (such as metoprolol, atenolol, propranolol, etc), often used to prevent rapid heart beat and nervousness from suppressive doses of levothyroxine. Very rarely, a beta blocker drug can cause significant amounts of hair to fall out. In such very unusual individuals, the hair will grow back within 2 to 6 months after stopping the beta blocker. This is so rare, that most physicians do not know about this unusual side effect. Never stop beta blockers suddenly (they need to be tapered slowly under a physician's guidance) to prevent the heart from beating severely fast.
Lastly, radioactive iodine DOES NOT cause hair loss at all. Any hair loss that seems to be associated with this is actually from the changes in thyroid hormone levels (see above).
—ThyroidCancerHelp, July, 2007
Hashimoto’s disease and thyroid cancer, co-existing
There are several studies, performed between 1998 and 2002 that analyzed prognostic features in patients with both thyroid cancer and Hashimoto's thyroiditis (AKA chronic lymphocytic thyroiditis). Most of them found that patients who had both of these diagnoses in their thyroid gland seemed to have a slightly less aggressive course of their disease; however, the effects are minimal and there are certainly patients in that category with very aggressive tumors. On the downside, if the person has Hashimoto's thyroiditis, then they have a greater chance of having anti-thyroglobulin antibodies that would impede the use of the thyroglobulin assay and complicate their disease status assessment.
—ThyroidCancerHelp, January, 2008
Hashimoto’s thyroiditis and suspicious nodules
Hashimoto's thyroiditis often proves to be a clinical dilemma. It is VERY common, involving almost one fifth of women and one tenth of men, much more common than thyroid cancer. When a gland has multiple nodular regions consequent to Hashimoto's thyroiditis, it is difficult to discern a difference from a gland with malignant nodules by its appearance on radiographic or nuclear studies.
The fine needle biopsy must be relied upon to provide this distinction. When the biopsy is interpreted as clearly benign, the issue is easy. When the biopsy is shown to reveal cancer, the decision for surgery is clear. However, in the presence of suspicious or indeterminate biopsy results and bilateral thyroid nodules, sometimes it is most appropriate for an experienced surgeon to perform a total thyroidectomy. In this way, the appropriate surgery for the cancer has been done. On the other hand, if there is no cancer (as long as the surgery has not caused any complications) there is a reasonable outcome since such a gland would be expected to eventually need thyroid hormone replacement treatment anyway.
—ThyroidCancerHelp, October, 2007
Hurthle cell adenomas (diagnosing)
Benign Hurthle cell adenomas are difficult to verify because they require the pathologist to fully document the ABSENCE of any evidence of tumor capsule or tumor blood vessel invasion (to make sure it's not a cancer). It is usually wise, for this type of diagnosis, to have an outside pathologist (preferably one with well-known expertise in thyroid cancer) to review the slides for a second opinion (a very, very good investment).
—ThyroidCancerHelp, July, 2007
Hypoparathyroidism and phosphorus
Hypoparathyroid patients do not typically need to limit their phosphorus intake in their diet unless their blood chemistry shows elevated phosphorus levels. Phosphorus levels and ionized calcium levels should both be monitored regularly by your physician to properly regulate your therapy. It is insufficient
to merely look at the total calcium level.
—ThyroidCancerHelp, December, 2007
Hypoparathyroidism: a primer
It's unfortunate that some physicians do not pay attention to appropriate management of hypoparathyroidism, nor teach their patients the necessary techniques and information regarding it. I do not know of any treatment that will affect basal ganglia calcifications consequent to hypoparathyroidism, but it's not clear that these are necessarily causing any attributable symptoms.
Below, is my "primer" on treating hypoparathyroidism. I hope that is proves helpful:
Therapy for hypoparathyroidism can sometimes be difficult. The usual dose of calcitriol (Rocaltrol®) is 0.5 mcg daily, but very rarely it can be increased to 0.75 mcg daily. Some patients need only 0.25 mcg.
The most important component of treatment is the oral calcium therapy. I use calcium carbonate (TUMS are a good source) because it is 40% calcium (500 mg of calcium carbonate contains 200 mg elemental calcium), whereas other calcium compounds are usually 20% or less calcium by weight. It is very important to split the calcium dose into every 8 hour or every 12 hour dosing. Sometimes it needs to be taken 4 times daily, but NEVER take all of the calcium together as a single dose. This is because the calcitriol works by helping the intestines absorb this oral calcium. Thus, it is important to split the dose so that there is always some calcium in contact with the intestines or the full 24 hours of each day. The dose must NOT be varied from day to day. Consistency is the essence of therapeutic success.
The quantity of oral calcium may vary from person to person. It's determined by measuring the IONIZED calcium on a consistent dosing of calcium carbonate and calcitriol (for at least 2 weeks) and making adjustments as needed. Some of my patients do well on as little calcium carbonate as 1000 mg (400 mg elemental calcium, equivalent to 2 regular TUMS) twice daily. Others may require as much as 5 TUMS (2500 mg calcium carbonate = 1000 mg elemental calcium) taken four times daily (total 4000 mg elemental calcium per day). Most people with hypoparathyroidism require something in between these extremes.
The target for therapy is an IONIZED calcium in the low normal range. This sometimes results in an elevated phosphorus, because the hypoparathyroid kidneys retain phosphorus in the blood and the calcitriol causes the intestines to also absorb more phosphorus into the blood. High phosphorus levels (which should be monitored by blood tests) are NOT good, particularly since they can cause kidney problems and make it more difficult to keep the calcium level up. For that reason, it is best to avoid dairy products as a source of calcium since they contain equally high phosphorus levels. Sometimes people have to analyze their diet to refrain from too many foods containing high phosphorus (a bit difficult to do since its in many otherwise "healthy" foods). Over time, the therapeutic regimen for treating the hypoparathyroidism should become second nature and easy, with almost never having any low calcium symptoms.
—ThyroidCancerHelp, July, 2007
Hypoparathyroidism (more on)
Paricalcitrol (Zemplar®) is an analog of calcitriol (Rocaltrol®) and is not particularly different in any way, aside from a slightly longer half-life and a greater cost. I find no reason for its use in my own practice and it would not be expected to produce any different effects or results.
One problem with some hypoparathyroid patients is that there is insufficient use of calcium carbonate. It is very rare for the dose of calcitriol to exceed a total of 0.5 mcg per day (I have only one patient on a dose as high as 1.0 mcg per day). Often a patient is not taking sufficient calcium on a regular basis. The dose of calcium carbonate can often be as high as 2000 mg taken four times daily (8000 mg per day, equivalent to 3,200 mg elemental calcium per day).
If such doses of medications are necessary to keep the IONIZED calcium levels normal, it is very unlikely that there would be any recovery of endogenous parathyroid function.
—ThyroidCancerHelp, August, 2007
Hypoparathyroidism (onset of)
Usually, hypoparathyroidism stemming from damage to parathyroid glands during thyroid surgery, reveals itself within a day or two from surgery.
Often the blood supply to these glands is temporarily compromised or the surgeon may have "re-implanted" a removed gland to a different location and the gland may not have resumed effective functioning for a number of days or weeks. In such cases, calcitriol and calcium therapy can be gradually tapered as the person becomes able to sustain their proper calcium levels without such help.
If there is permanent hypoparathyroidism, usually shown as continued need for medication beyond 4-6 months from the surgery, then it is very unusual for someone to recover their parathyroid function later on, although I have a few patients whose parathyroid glands recovered 1-2 years later. In situations in which all four glands have been removed, there is no such spontaneous recovery.
Late onset, months or years later, of hypoparathyroidism is very unusual and should suggest a need to investigate other causes, such as Vitamin D deficiency.
—ThyroidCancerHelp, August, 2007
Hypothyroidism (abnormal lab tests from)
When people are made hypothyroid for radioactive iodine and scanning, there are many blood tests that are caused to be abnormal due to the hypothyroidism. These transient abnormalities normalize after thyroid hormone treatment has been resumed for a month or more. Among these tests are: elevated cholesterol levels, elevated liver enzyme tests, lowered sodium, and slightly increased creatinine levels. It is usually inappropriate for such test abnormalities to prompt any diagnostic studies or therapeutic interventions unless extremely severe and associated with other clinical indications for disease.
—ThyroidCancerHelp, October, 2007
Hypothyroidism after scan/treatment without Cytomel
If, for some reason, a person chooses to be taken off of levothyroxine for 6 weeks before a radioactive iodine scan or therapy without using Cytomel to support them for the first 4 weeks, then they would be considered hypothyroid by 10-14 days after stopping the levothyroxine.
—ThyroidCancerHelp, November, 2007
Hypothyroidism and carpal tunnel syndrome
Carpal tunnel syndrome is a situation in which the nerves that pass through the ventral aspect of the wrists, the "carpal tunnel", are compressed by swelling of these tissues and the nerve damage causes pain and difficulty with finger movement and sensation. During periods of significant hypothyroidism, the extra swelling of the body tissues can exacerbate this carpal tunnel syndrome, making a minimal problem much more symptomatic and obvious. Typically, hypothyroidism itself does not create a carpal tunnel syndrome without there having been some pre-existing compromise of the nerves in the wrist. The treatment for this problem often starts with splinting of the wrists at night, but usually progresses to a surgical treatment in which the constricting tissues at the wrist are "released" by the surgeon.
—ThyroidCancerHelp, March, 2008
Hypothyroidism and driving
The following warning is verbally given to all of my patients, as well as a written copy, for when they stop their Cytomel in the hypothyroid preparation for I-131 scanning or therapy:
Please note that you will become significantly hypothyroid at this time and you are advised to avoid driving or operating dangerous machinery. Sometimes my patients do not heed this warning and this has been responsible for some auto accidents. Please note that auto accidents may involve other people besides the hypothyroid driver. It would not be wrong to call a severely hypothyroid driver an "impaired driver", similar to drivers taking some prescription medicines, alcohol, illicit drugs or other similar items which affect their driving abilities. Likewise, my hypothyroid patients who are nurses, pharmacists, physicians, or other professionals with like responsibilities, are advised to be aware of these problems when prescribing medicines, running IVs or making important decisions. A word to the wise SHOULD be sufficient.
Much is often said concerning whether people feel capable of driving while hypothyroid, despite our warnings to refrain. There is also the legal issue to consider. Should a hypothyroid driver be in an accident, particularly with loss of life occurring, even if absolutely blameless for causing the accident, they could be legally defenseless. Should an opposing attorney or prosecutor find out that the driver was hypothyroid, innocence would be hard to prove. This would be similar to finding the driver with an illegal blood alcohol level, despite an accident which they did not contribute towards. Likewise, should the insurance company find out about the hypothyroid status of the driver, it might be difficult (if not impossible) to obtain financial payments which would
have otherwise been easily obtained. There are may aspects of good common sense to consider regarding this issue.
It is both stupid and unethical to choose to drive a motor vehicle while you are impaired from hypothyroidism. Regardless of a cavalier attitude towards your own safety, such a situation would make you a societal menace, fully capable of drifting across the center line of the road and "taking out" a busload of children. The physician who knowingly prepares a patient for radioactive iodine scanning or therapy using hypothyroid withdrawal has an ethical duty to warn the patient not to drive or operate dangerous machinery. In fact, if the physician becomes aware that the patient is still doing dangerous activities while impaired, he/she has a duty to warn others. For example, when one of my patients was seen still working as a school bus driver despite TSH levels in \ the 100's, I was forced to contact the school district and had her suspended. In another case, a patient was still driving trucks loaded with tons of coal down Kentucky mountain roads while severely impaired. When the coal mine supervisor was not sufficiently impressed to have him stop, the state police were happy to oblige my telephone call. It is sad that there are some people that are so self-centered and uncaring of others that they would get behind the wheel and place innocent bystanders, including their own children passengers, at risk of death…. For a full discussion of the ethical issues, please see the forth-coming December, 2007 issue of THYROID. Dr. M. Sara Rosenthal will have a scholarly analysis of this problem in that issue.
—ThyroidCancerHelp, November, 2007
Hypothyroidism and temperature sensitivity
During periods of hypothyroidism, ALL body tissues are affected and perform suboptimally. After restoration of thyroid hormone levels, these body tissues recover their normal function. It would not prove fruitful to attempt to ascribe persistent symptoms of any sort to previous hypothyroidism if thyroid hormone levels are no longer low.
There are often a variety of causes for the sensation of fluctuating sensitivity to temperature. One cause that is sometimes related to thyroid cancer therapy is the consequence of radioactive iodine causing perimenopausal women to move into menopause a little sooner than if they had not been treated with radioiodine. For younger women, with normal ovarian function, the causes of temperature sensitivity changes are not so clear.
—ThyroidCancerHelp, February, 2008
Hypothyroidism, asymptomatic
Hypothyroidism, in preparation for radioactive iodine scans and therapies, is handled extremely differently by different people. Some feel as if they are on the brink of collapse, while others may not perceive too much difference. This is similar to the different responses of people when they drink alcohol; some can drink half a bottle of wine without much effect while others get tipsy after one glass. The hypothyroid preparation period may produce different symptoms from the first week to the second week, depending upon the length of time since the levothyroxine was stopped and Cytomel initiated. Nonetheless, it is very important to remember that, despite the absence of severe symptoms, hypothyroid individuals should not consider themselves safe drivers. For an academic discussion of this, please see Dr. M. Sara Rosenthal's recent publication:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieveanddb=PubMedanddopt=Citationandlist_uids=18177258
—ThyroidCancerHelp, January, 2008
Hypothyroidism (recovery is slow)
Once a person has become sufficiently hypothyroid for radioactive iodine scans or therapy, it takes some time to get back to normal. Even if the full dose of levothyroxine is re-started at 24 hours after the radioactive iodine treatment (and it should be), it takes a full month before thyroid hormone levels start to approach normal. It should not be a surprise to still feel tired and exhausted within only a week after starting levothyroxine.
To help with this, I usually start the full dose of levothyroxine and also a tapering schedule of supplemental liothyronine (Cytomel) over the first three weeks to boost the person into feeling better faster.
It is important to avoid operating motor vehicles until at least two weeks after starting levothyroxine since a severely fatigued hypothyroid driver is unlikely to be a safe one.
—ThyroidCancerHelp, August, 2007
Hypothyroidism slows down the gastrointestinal system
Although gastrointestinal issues can affect any of us at any time, there are certain ones that are more common during the period of time that thyroid hormones are stopped for radioactive iodine scans or therapies. The rate at which food is transported from the stomach to the small intestines, then through the small intestines and into the large intestines, and then finally out, is partly dependent on thyroid hormone.
When there is too much thyroid hormone, people note frequent bowel movements and sometimes feel that things just run right through them.
When there is too little thyroid hormone, such as during hypothyroid preparations, everything slows down. It is very common to have gastroesophageal reflux during this time. I often advise patients to sleep with the head of the bed elevated. The stomach takes longer to empty itself into the small intestine and this causes bloating, fullness, and again reflux. The slow transit of stools through the large intestines can cause significant constipation, bloating, and much odoriferous gas. Everything gradually gets better when the thyroid hormone levels
are restored.
—ThyroidCancerHelp, July, 2007
Hypothyroid preparation (duration of)
Proper hypothyroid preparations involve stopping levothyroxine for six weeks, with the first 4 weeks taking Cytomel twice daily. With this method, a person is only off of thyroid medication for the two weeks preceding the scan/therapy week (a total of just under 3 weeks off of thyroid hormone). Those patients undergoing a dosimetry study, for the purpose of implementing high dose (>200 mCi) radioactive iodine therapy, are off of their thyroid hormone for an additional week (for a total of 3 and 1/2 weeks) before thyroid hormones are resumed.
I cannot understand the reason why a patient would be denied the temporary support with Cytomel¨ (liothyronine) for the first 4 weeks or why they should be further delayed in resuming their medications under most circumstances. Please note that thyroid hormone therapy can be resumed 24 hours after radioactive iodine treatment, even though the post-therapy whole body scan may be performed at 2-10 days later, because this scan images radioiodine taken by the tumor during the first day only.
—ThyroidCancerHelp, August, 2007
Hypothyroid preparations and emotional changes
The usual method of hypothyroid withdrawal is to stop the levothyroxine 6 weeks before the scan or therapy, putting the patient on Cytomel for the first 4 weeks. This is to avoid hypothyroid symptoms for the first month. The usual dose of Cytomel is 25 mcg twice daily. Some people need a bit less (half the dose, 12.5 mcg, three times daily, for example). If this Cytomel dose is being taken, there should not behypothyroid symptoms for the first 4 weeks.
Cytomel produces a "roller-coaster" effect in some people with peaks and troughs of levels in the blood. This can cause some people to have mood swings. If this occurs, I often suggest that the person split the 25 mcg pill in half and take 12.5 mcg in FOUR doses spread out during the day.
Certainly, when the Cytomel is stopped, for the last 2 weeks of the 6 week withdrawal, as well as during the week of scanning and for 10 days after, while thyroid hormone levels are being restored (a total of around 4 weeks), there is a significant time of hypothyroidism. Although some people may have changing emotions during this period, most are somewhat depressed. It's a very good idea to warn family members and caregivers about the emotional effects of this period so that they can make allowances for inappropriate behavior and can give their greatest support.
—ThyroidCancerHelp, July, 2007
Hypothyroid symptoms can actually be from sleep apnea
There are a number of very common traps that people fall into. One of the most common is the assumption that tiredness always is a symptom of a problem with thyroid hormones.
The suppressed TSH is proof positive that each cell of your body is getting more than sufficient amounts of thyroid hormone. The proper question should be: "What else could be causing me to be tired?"
In a large number of cases, the answer is that the tiredness is caused by insufficient deep (REM) sleep caused by sleep apnea syndrome. The difficulties in getting sufficient oxygen while sleeping causes your brain to "wake you up" out of REM sleep, while not actually reaching a conscious state. The result is severe chronic sleep deprivation, often feeling as bad or worse than hypothyroidism. The answer is to have a formal sleep lab study performed and there are a variety of treatments once this diagnosis is confirmed.
There are a number of other causes; however, I've found sleep apnea to be severely undiagnosed and very common, particularly in overweight or snoring individuals.
—ThyroidCancerHelp, July, 2007
Hypothyroid symptoms DO NOT always come from Hypothyroidism
Nearly ALL of the symptoms that can be felt with hypothyroidism can be seen in totally unrelated conditions that are have normal thyroid hormone levels and are NOT hypothyroidism. They include: sleep deprivation (from sleep apnea syndrome), obesity, physical deconditioning, dry skin from heating systems, fibromyalgia, depression, etc., etc., etc.
The key to proper diagnosis and treatment is to first EXCLUDE hypothyroidism by verifying normal TSH and free T4 levels, then looking elsewhere for the correct cause of the symptoms.
—ThyroidCancerHelp, August, 2007
Hypothyroid, using antidepressant medications while
Hypothyroid preparation for radioactive iodine decreases liver function and kidney function in a temporary fashion. This means that many medications that are metabolized by the liver or excreted by the kidney may require dosage adjustments during such a period. For most medications, this temporary state of affairs does not require and changes; however, for others it may be important. For that reason, when using antidepressants or other medications, it's good to remind your physician of the temporary metabolic changes so that the medication can be more carefully monitored or adjusted if necessary. Antidepressant medications will continue to provide the desired activity, but people feel much better after restoring their thyroid hormone levels.
—ThyroidCancerHelp, October, 2007
I
I-123 as a scanning agent (I do NOT advise using)
I DO NOT advise using I-123 as an imaging agent for thyroid cancer. Its radiokinetics are much inferior to I-131 and it is far less informative. The issue of "tumor stunning" that is mentioned above is not very significant a problem and can be dealt with in far more effective ways than compromising the whole body scan with I-123…
[continued from another posting]:
The reasons why I-123 is not the best agent for imaging thyroid cancer using whole body scans follow:
1) The very brief half-life of I-123 results in significant loss of signal in target tumor metastases by 48 hours after dose administration, the optimal time for clearance of non-target tissues. This results in a poor signal-to-noise ratio at that time. The opportunity to view at 72 hours is completely lost with this isotope. To compensate for the rapid decay of I-123, images are often taken at 24 hours; however, there is far too much background at that time to distinguish key areas, such as diffuse pulmonary uptake or to distinguish abdominal/pelvic sites from overlying stool. These factors overcome the minimal enhancement of the image due to the better gamma emissions from this isotope. I-131 provides better imaging using proper techniques.
2) The idea of tumor stunning, meaning that the tracer dose of I-131 used for imaging will impair the subsequent uptake of the treatment dose of I-131, may be largely mythical, consequent to imaging technique. This has recently been demonstrated by an excellent analysis of Dr. Sissonand and associates; [Sisson JC, Avram AM, Lawson SA, Gauger PG, Doherty GM 2006 The so-called stunning of thyroid tissue. J Nucl Med 47:1406-1412]. For the very rare circumstance when an actual impairment of treatment effect is considered evident in a particular case, it is a very simple process to deal with. Merely avoiding administering the treatment dose until at least 6 months later (using a separate hypothyroid and low iodine diet preparation) will permit a treatment without any preceding scan. For the vast majority of patients, there is no need to fear this phenomenon.
Although a complex issue, not very well appreciated by most nuclear medicine physicians, the use of I-131 for both scanning and therapy is the best lesson to learn.
—ThyroidCancerHelp, September, 2007
I-131 dosing, determinants of
The amounts of radioactive iodine given for therapy are, unfortunately, quite arbitrary and based more on habit than on science. For many years, the most common dose was 29 mCi because this was the highest dose that did not require hospitalization. Many
considered this to be standard and higher doses were considered "high". This is despite excellent studies that suggested that a minimum of 100 mCi was necessary to definitively ablate a thyroid remnant after surgery.
In my practice, I use 100 mCi as the minimum dose for small tumors that are not invasive and have no spread to any site outside of the thyroid bed (where the thyroid used to be). Local spread in lymph nodes in the neck is treated with 150 mCi. Invasive disease in the neck is treated with 200 mCi (provided that the patient has normal kidney function, otherwise the dose may need to be lower). When there are metastases (spread tumor) outside of the neck (such as bones or lung or liver), I perform a "dosimetry study" that tells me what is the highest dose that is "safe" for the patient. This can be as high as 900 mCi for a single dose or as low as 120 mCi (for example, in an elderly woman with poor kidney function).
What one doctor considers a "high" dose, others (such as myself) might consider it to be a "low" dose. There is no consistency between physicians or institutions.
As far as using Salagen prior to and during radioactive iodine treatment, this is not an approach that has been demonstrated to be of benefit. In fact, there is evidence that stimulation of saliva during radioactive iodine therapy is likely to increase the chance of salivary damage, not prevent it. {See: Nakada K, Ishibashi T, Takei T, Hirata K, Shinohara K, Katoh S, Zhao S, Tamaki N, Noguchi Y, Noguchi S 2005 Does lemon candy decrease salivary gland damage after radioiodine therapy for thyroid cancer? J Nucl Med 46:261-266}.
LIthium therapy during radioactive iodine treatment may enhance the treatment by prolonging the retention of the radioactive iodine in the tumor in the small percentage of tumors that release the I-131 too quickly; however, to do this it must be continued for 5 days after the I-131 is given, not 24 hours. {See the study I participated in: Koong SS, Reynolds JC, Movius EG, Keenan AM, Ain KB, Lakshmanan MC, Robbins JR 1999 Lithium as a potential adjuvant to 131I therapy of metastatic, well differentiated thyroid carcinoma. J Clin Endocrinol Metab 84:912-916}.
—ThyroidCancerHelp, June, 2007
I-131 preparation for aggressive thyroid cancers (initial)
When there is a new diagnosis of tall cell variant papillary thyroid cancer, following appropriate total thyroidectomy surgery and modified node resections, it is very important to have the optimal approach to radioactive iodine scanning and therapy. In addition, it is very useful to have a full "tumor staging" work-up (being very careful to avoid contrast dye for xrays and CT scans; gadolinium for MRIs is fine).
In our hands, a staging work-up consists of a high resolution CT scan of the chest (performed WITHOUT ANY contrast), a metastatic bone survey (plain xrays of all of the bones of the body; "bone scans" do not work for thyroid cancer), and (if the tumor is particularly large or invasive) an MRI of the abdomen (using gadolinium contrast). This presumes that there are no symptoms of possible disease outside of the neck. Additional studies may be done if there are specific symptoms. If the patient mentions back pain or sensation changes or weakness of the arms or legs, we do a screening MRI of the entire spine to make sure that there are no tumors pushing on the spinal cord. If the patient notes severe headaches or has evidence of a seizure or visual changes, we do an MRI of the head (with gadolinium).
Preparation for the first I-131 whole body scan is critical. Despite the advances made with Thyrogen, radioactive iodine dose for dose is far more effective with a hypothyroid (thyroid hormone withdrawal) preparation than with Thyrogen; particularly important when dealing with potentially aggressive tumors.
A very careful low iodine diet is critical for 2 weeks before the radioactive iodine scans and treatment and is continued until 24 hours after the radioactive iodine therapy dose is administered. Although the ThyCa website has a free "recipe exchange" that can be downloaded, it doesn't really qualify as a professionally prepared cookbook and contains a number of inaccuracies and inappropriate restrictions. The best information can be found in Norene Gilletz's "The Low Iodine Diet Cookbook" available on Amazon or at www.lidcookbook.com.
If there has been previous exposure to iodinated contrast dye for CT scans or angiograms, going on a low iodine diet for one week and getting a complete 24-hour urine collection on the last day of the diet, permits this urine to be analyzed for total iodine. An excellent low iodine preparation will render the total 24-hour urine under 50 micrograms of iodine; however values under 100 mcg are acceptable. If much higher than this, the diet and urine collection should be repeated monthly until the stable iodine has cleared.
If the tumor was originally invading through the capsule (covering) of the thyroid gland and into the muscles or vital structures of the neck, we would plan to do a dosimetry study so that we could be prepared to treat with a maximally tolerated safe radioactive iodine dose if the tumor has spread outside of the neck. On the other hand, in institutions where dosimetry is not available, some physicians might administer a dose as high as 200 mCi without doing a preceding whole body scan. ALL radioactive iodine therapies MUST be followed by a whole body scan (we find the best time at 48 hour after the treatment) within 2-7 days after the treatment to show where the tumor is in the body that has taken up some of the radioiodine dose.
—ThyroidCancerHelp, July, 2007
I-131 scans can be misinterpreted: uptake in stomach and intestines
It is important to realize that the interpretation of an I-131 whole body scan (WBS) is not always performed properly, even by trained nuclear medicine physicians. I am often required to get to the bottom of situations in which perfectly clean WBSs are misinterpreted. Some common errors include: 1) mistaking salivary gland uptake for tumor sites; 2) mistaking radioactive saliva coating the esophagus for tumor sites; 3) mistaking gastric uptake for tumor; 4) mistaking hepatic "blush" for liver metastases (organified radioiodine from tumors other sites of the body is taken up by the liver without tumor being present in the liver); 5) kidney/ ureter/bladder uptake sites mistaken for tumor sites; 6) radioactive stool scattered in the small and large intestine being mistaken for tumor sites; 7) stool in the appendix or colonic diverticula mistaken for tumor sites; 8) radioactive perspiration or saliva on the skin mistaken for tumor sites; 9) physiological breast uptake or fibrocystic breast uptake mistaken for tumor metastases; 10) benign cysts in the neck/ kidneys/ lungs/ liver/ etc. mistaken for tumor metastases; 11) sucking on a pigtail with radioactive saliva that lays across the neck mistaken for tumor metastases; 12) pulmonary bronchiectasis mistaken for tumor metastases to the lungs; 13) etc. and etc. and etc.
Although it is quite possible to have thyroid cancer metastases in this situation, it is even more likely that the scan has been misinterpreted. When we see such unusual scans, we will do the appropriate maneuvers (from having the patient take a shower to wash the skin, to chewing on a lemon to disperse radioactive saliva, use laxatives to dissipate radioactive stool, or to performing extra lateral chest views to move a woman's breasts out of the way, etc., etc., etc.). If all of the reasonable and known causes of false-positive WBSs are effectively dealt with, THEN we investigate the site of activity with additional scanning and radiological studies.
—ThyroidCancerHelp, July, 2007
I-131 (tearing of the eyes: nasolacrimal duct blockage from)
It is now a well known complication of radioactive iodine therapy (in around 5-10% of patients) to have blockage of the small tube that normally carries tears from the inner corner of the eye to the interior of the nose, the nasolacrimal duct. The presence of this duct is why your nose tends to run when you've been crying or tearing excessively.
The portion of the nasolacrimal duct that is nearest the eye can become scarred and block the passage of tears into the nose. The symptoms of this are a continuous tearing and tears running down your cheeks, even when you're not crying. Only very experienced ophthalmologists are able to deal with this effectively. Sometimes they can put a thin probe into the duct and open it up. Sometimes they need to place a hollow tube into the duct, called a stent, to keep it open. It's unfortunate that many physicians are unaware of this issue.
—ThyroidCancerHelp, July, 2007
I-131 therapy doses and the lung (more on)
The limits of radioactive iodine in the lung are based on the specific radioactive iodine retained in the lung at 48 hours for a single dose, not the cumulative dose. For example (during the preceding tracer dose study), if there is 30% of the administered dose retained in the body at 48 hours and 50% is in the lungs, then (based on the 80 mCi limit) one could safely tolerate a 533 mCi treatment dose. On the other hand, there is an independent limit based upon the dosimetric assessment of the red marrow exposure (see my earlier posting about dosimetry) that usually is reached before one reaches the lung limit.
There are MANY reasons to be short of breath, from emphysema to asthma, and the questioner provides no information about the dosimetric parameters of their therapy. For that reason, it is not possible to comment about the very unlikely chance that any of the pulmonary problems are related to the radioactive iodine therapy.
—ThyroidCancerHelp, December, 2007
I-131 therapy (high dose) is best for distant disease
Unfortunately, one of the common problems encountered when physicians of varying expertise treat distantly metastatic thyroid cancer is the use of radioactive iodine doses that are too low to achieve a useful clinical response. In my practice, patients with distant disease (outside of the neck) that is able to take up radioactive iodine, are evaluated with a radioactive iodine dosimetry study. This method permits me to determine the maximal dose of radioactive iodine that can be given with reasonable safety to that specific patient at that specific time. This dose can range from 120 mCi to 950 mCi as a single dose, based on the dosimetry results. I find this approach to be the most effective one.
Sadly, most patients are not able to reach a physician capable of this dosimetry method of calculating I-131 therapy. Despite this, many physicians can often provide effective treatments with empiric doses of 200 to 250 mci I-131. The most important thing is to avoid the use of repetitive low dose (<200 mCi) therapies that fail to resolve the disease and cause greater side effects in the end.
—ThyroidCancerHelp, July, 2007
I-131 therapy (hypothyroid vs. Thyrogen preparation for)
There are a number of features of radioactive iodine therapy that distinguish the effects of injecting Thyrogen from a hypothyroid preparation.
First, when a person is hypothyroid, the kidney functions at one third the normal activity. In the hypothyroid person, a dose of radioactive iodine circulates longer in the blood before it is passed out in the urine. Since any tumor cells do not instantaneously take up the radioactive iodine, the longer that the radioiodine circulates, the more of it is able to be taken into the tumor.
Second, the effects of TSH, whether injected (Thyrogen) or produced by hypothyroidism, are also not instantaneous. That is, the thyroid cancer cells take several days to fully respond to the TSH, synthesize more iodine transporters, and produce more enzymes needed to hold on to the radioactive iodine, once it is taken into the cancer cell (organification). The brief time that Thyrogen is on board, prior to getting the radioactive iodine dose is a compromise necessitated by the expense of the injections, and the logistics of administering it for longer periods of time. Hypothyroidism exposes the thyroid cancer cells to greater TSH effects.
Truly, there are many people who may be adequately treated with protocols being devised using a Thyrogen preparation. Nonetheless, it is an inferior compromise to a well-done hypothyroid preparation. In minimal and well-responsive tumors, the differences may not be significant; however, in potentially aggressive thyroid cancers, every advantage of a hypothyroid preparation should be used.
—ThyroidCancerHelp, July, 2007
I-131, which thyroid cancers do not require it
It is not necessary to perform radioactive iodine therapy and whole body scanning for EVERY case of thyroid cancer. Those cases that do NOT routinely get radioiodine therapy are unifocal (single) papillary cancers (usual papillary, follicular variant of papillary, occult sclerosing papillary) that are present inside the thyroid gland (do not penetrate the thyroid capsule) and are do not have any clinically obvious local or distant metastatic disease. For such patients, we generally advise them to perform regular (monthly) neck self exams, take an appropriate dosage of levothyroxine to keep the TSH only slightly suppressed (just below or at the lower edge of the normal range) and make certain that their primary care physician provides regular check-ups. We also obtain a baseline thyroglobulin measurement (when the TSH is at the target level) for future comparison (and have their primary care physician check it yearly with routine labs). For most such patients, this is sufficient management.
On the other hand, should the tumor be an aggressive variant of papillary cancer (tall cell, columnar cell, Hurthle cell), extend through the thyroid capsule, reflect any other type of radioiodine-responsive histology (follicular, Hurthle cell, insular, etc.), or exhibit any evidence of lymph node metastases or distant disease, we would assertively treat with radioactive iodine (our minimal dose is 100 mCi for only thyroid bed remnant) and use radioiodine scanning as part of long-term follow-up.
—ThyroidCancerHelp, November, 2007
Insular thyroid cancer: dealing with persistent local disease
Some important information has been omitted from the question above. I'll have to make some assumptions: 1) the "nodes" in question are in the neck; 2) the CT scans were performed with iodinated contrast; and 3) although the results of the radioiodine scan performed 2-7 days after the last radioiodine therapy (the "post-therapy whole body scan") results were not given, I presume them to have been negative.
Insular thyroid cancer is often a very aggressive tumor. Although it may sometimes take up radioactive iodine and be responsive to such therapy, it frequently fails to take it up or loses this ability later in the course of the disease, making radioactive iodine therapy or scans useless. A problem with assessing radioactive iodine uptake in these tumors is that they are very sensitive to the effects of non-radioactive (stable) iodine which prevents the radioactive iodine from going into the tumor cells, sometimes falsely making appear unresponsive to radioactive iodine. CT scans of the neck are usually performed with iodine (stable) contrast dye and its effects on preventing radioactive iodine uptake can sometimes persist for more than 6 months. This possibility always needs to be taken into account.
On the other hand, PET scans present a bit of a "Catch-22" (read Joseph Heller's book). If tumors (or lymph nodes) "light up" on a PET scan, this can be supportive evidence that they contain cancer cells; however, tumors that "light up" on PET scans are usually more rapidly growing and less likely to take up radioactive iodine than those that are not. It would be good to have a fine needle biopsy that shows thyroid cancer cells, but sometimes this may be difficult to do if the local physicians are not sufficiently skilled in the technique.
As mentioned in earlier postings on this site, when there are lymph nodes in the neck that contain thyroid cancer (based on their increase in size, elevated thyroglobulin levels and positive uptake on the PET scan) usually the best course of action is to have an excellent surgeon perform an appropriate modified neck dissection, then to have external beam radiotherapy to the neck and superior mediastinum (the mid upper part of the chest). Although there may be other sites of metastatic tumor (for example: lungs or bones), it is important to deal with tumor in the neck in this fashion because this is a particularly vital part of the body.
—ThyroidCancerHelp, July, 2007
Iodinated contrast dye (decision when to use)
In all of my patients with thyroid cancer, I suggest that they approach the issue of CT scan contrast dye with common sense. If they have an emergency situation, then contrast dye should be used without question, such as: chest pain requiring cardiac catheterization with dye, ruptured cerebral aneurysm requiring an angiogram, or automobile accident with CT scans to assess for internal bleeding. On the other hand, if the contrast dye is to be used for an optional study, particularly if it can be delayed until after the consideration of radioactive iodine use is dealt with, then it should be delayed. If alternative radiographic techniques, such as ultrasound or MRI can be substituted with adequate utility, then this could be considered. Above all use common sense.
—ThyroidCancerHelp, October, 2007
Iodine contrast: you can't make it go away faster
Iodinated contrast will take anywhere from 2 to 12 months to clear. There is NOTHING that can be done to accelerate this process; not diuretics, not selenium, not a low iodine diet. Unfortunately, a little bit of knowledge is dangerous. Areas of the world with endemic iodine deficiency are also usually selenium deficient and both deficiencies go hand in hand; however, they do NOT cause each other. Please do not take well-intentioned, but completely wrong, advice.
The appropriate thing to do, when exposed to such iodinated contrast, is to do a one-week low iodine diet and collect a 24-hour urine sample for total iodine on the last day. If the amount of iodine is less than 100 mcg total, then there will not be significant interference. If the amount of iodine is much higher, I have my patients repeat the one-week-LID-with-urine-study for the next month. Eventually, the iodine will drop sufficiently to proceed with radioiodine plans.
—ThyroidCancerHelp, August, 2007
Iodine isotope choice for scanning
I do not use I-123 for scanning thyroid cancer patients because I find that it has less sensitivity for detecting tumors, particularly when using delayed imaging to reduce non-specific background from the scans. I do not find it to be of any advantage and it is far more expensive than I-131. The issue of "stunning" (having the scan radioiodine dose interfere with the tumor cell taking up the subsequent treatment dose of radioiodine) is highly over-rated and does not occur very frequently in my practice (although we use very sensitive procedures to look for it).
In the rare circumstances when radioiodine scans are positive, and the subsequent treatment dose effectiveness is reduced by "stunning," it is very easy to remedy the matter by performing a radioactive iodine treatment 6—12 months later without doing a preceding scan. Such remedies are not needed very often at all.
Thyrogen stimulated scans are generally less sensitive for detecting thyroid cancer metastases than identically performed scans using a hypothyroid preparation. For that reason, I typically refrain from using Thyrogen until a hypothyroid-prepared scan is completely clean (with undetectable thyroglobulin) and I am confident that the tumor does not show features suggesting it to be particularly aggressive. Not all physicians agree with this approach. In my large practice population of thyroid cancer patients, I generally perform equal numbers of Thyrogen-prepped scans and hypothyroid-prepped scans, each approach tailored to the individual features of each patient.
—ThyroidCancerHelp, June, 2007
Iodine uptake in breasts
Normal female breasts are able to concentrate radioactive iodine in the same ductal tissues that produce milk. In young healthy breasts, this can often be confusing on radioactive iodine scans of the chest. Often I have to get lateral views of the chest to make sure that the regions that mildly "light up" are actually breasts and not in the underlying lung. The iodine uptake is even greater in the breasts of actively lactating women; however, such women should never be given radioactive iodine.
—ThyroidCancerHelp, October, 2007
L
Levothyroxine and alcohol
There is no problem [having] alcohol while taking levothyroxine. It will not interfere with absorption in any way and at any time.
—ThyroidCancerHelp, October, 2007
Levothyroxine and calcium (taking)
The timing of medications should be as optimal as possible within the practical context of living a normal life. I suggest that people take their levothyroxine as soon as they wake up in the morning so it is as far removed from breakfast (when the first calcium dosage is taken) as is practical for their daily routine. The time from the levothyroxine to the breakfast may be anywhere from 20 minutes to two hours, depending on how fast people get dressed and out the door to work. It's not necessary to wait a full 5 hours (unless one is waiting to take iron supplements or cholestyramine; medications that block levothyroxine absorption much worse than calcium). That small difference is usually sufficient. The key is consistency, so that the levothyroxine dose titration takes care of any minor issues arising from the calcium.
—ThyroidCancerHelp, December, 2007
Levothyroxine and coffee
[A recent study found impaired absorption of levothyroxine when taken with coffee.] Taking levothyroxine WITH hot coffee/espresso will impair the effects of the levothyroxine; however, I suspect that this is not due to impaired absorption from caffeine. It has already been well established that levothyroxine is quite heat-sensitive. I suspect that the temperature of the stomach contents will be sufficiently elevated by a cup of hot coffee to degrade the hormonal content of a levothyroxine pill that is also in the stomach. Their results suggest that the coffee should not be taken within 30 minutes of the levothyroxine; after 30 minutes there isn't any effect of coffee on impairing the levothyroxine levels. Unfortunately, this possibility could have been addressed by comparing the ingestion of COLD coffee and levothyroxine with the ingestion of HOT coffee and levothyroxine. Regardless of the mechanism of this effect, it supports the advice that I've been giving my patients for many years.
Take your levothyroxine as soon as you wake up, so that it is as far from when you typically eat breakfast/drink coffee as your routine will permit. It is likely that there would be at least one half hour from the time that one takes the levothyroxine until the coffee meets one's lips.
—ThyroidCancerHelp, March, 2008
Levothyroxine: a primer
With reference to estrogen therapy, applying to both oral and transdermal treatment: Taking estrogens (of any sort) do not necessarily alter the daily dosage of levothyroxine (of any brand).
Their effect on total thyroid hormone levels in the blood is due to their influence on raising the levels of thyroxine binding globulin (TBG; a protein made by the liver which transports levothyroxine in the blood)[Ain KB, Mori Y and Refetoff S (1987) Reduced clearance rate of thyroxine-binding globulin (TBG) with increased sialylation: a mechanism for estrogen-induced elevation of serum TBG concentration. J Clin Endocrinol Metab 65, 689-696]. Since the rate of disposal and metabolic consumption of levothyroxine is only dependent upon the portion which circulates "free" (unbound to TBG and other related proteins), any alteration in TBG levels ultimately results in a new steady-state without clinically affecting the treatment.
Everyone on thyroid hormone therapy has their medication adjusted based on the intracellular concentration of thyroid hormone, which is reflected by the TSH. Usually the dosages of estrogens used in modern medications are not high enough to cause any change in the daily dosage of levothyroxine and there will not be any change in the TSH. The bottom line here, as in the quoted posting above, is to monitor the TSH.
On the other hand, estrogen levels and other physiological changes associated with pregnancy frequently cause significant re-adjustments in the daily dosage of levothyroxine. Some women require their levothyroxine dose to be increased to 150% of previous dosages. After delivery, they usually need to return to their original dosage. This is why it is critical to have the TSH level measured monthly while pregnant.
In reference to general principles of taking levothyroxine, including the effects of iron medications:
The mean suppression dose of levothyroxine is 2.0 micrograms per kilogram (2.2 lbs) per day. For example, a 165 lb person would average 150 micrograms daily to suppress their TSH. Of course, there is a wide range of variation and there are many factors which are involved.
1. Levothyroxine (Synthroid, Levoxyl, Levothroid, etc) is exquisitely sensitive to heat. If exposed to the sun-heated interior of a parked automobile, or a shelf above the stove, or left sitting on the radiator, such pills will forever lose their potency, even if later cooled down. Women (in particular) often make the mistake of carrying the pill bottle in their purses, which are often exposed to wide fluctuations in temperature.
2. Absorption is best on an EMPTY stomach: usually best in the early AM at least one hour before eating breakfast.
3. If a pill is missed, always make it up. For example, if you forgot to take your pills over a weekend, on Monday you should take all 3 doses together. Since the half-life of levothyroxine is one week, such a thing is not only NOT dangerous, but very necessary to avoid losing TSH suppression.
4. Titration of doses to suppress TSH but not cause tachycardia or other evidence of thyrotoxicosis can be difficult in some patients, sometimes requiring dose changes of as little as 10%. For that reason, even missing one pill per week without making it up would cause a variation of more than 14% of the weekly dose. For that reason, NEVER miss your pill, or make it up if you do (as in #3 above).
5. Iron-containing medications and iron-containing vitamins will bind to levothyroxine and interfere with absorption. So will sucralafate (Carafate), cholestyramine, large doses of aluminum hydroxide gels (Maalox, etc), very large doses of calcium, and soy milk/protein supplements. If any of these items must be consumed, they should be taken 5 hours away from the levothyroxine dose. [note: estrogens and birth control pills do NOT interfere]
6. KNOW YOUR PILLS. Not too infrequently, my patients may be given the wrong dose or the wrong pill by the
pharmacist. Check your pills BEFORE you leave the pharmacy. Do not look at the label. Examine the pill itself. Note the characteristic color and numbers on the pill which denote the correct strength. Check the expiration date and ask for the date from the stock bottle. Levothyroxine pills degrade at around 5% of the dose per year by just sitting in the bottle under PERFECT storage conditions. Never use OLD pills (over one year old) if you have access to fresh ones. There have been situations reported when the stock medication dispensed by the pharmacy had been transported long distances in hot truck vans before it had reached the pharmacy, rendering all of the medication badly degraded despite appearing as "new" pills.
7. If you are the least bit forgetful, buy a day-of-the-week pill dispenser and use it religiously.
8. If these precepts are followed PRECISELY, your physician should be able to lower your daily dose to the lowest dose which suppresses your TSH (I prefer TSH < 0.10) to avoid stimulation of hibernating thyroid carcinoma cells. This will also permit the least long-term side effects (however minor) of TSH suppression.
—ThyroidCancerHelp, July, 2007
Levothyroxine dosing and pregnancy
Pregnant patients taking levothyroxine (either for hypothyroidism or thyroid cancer) frequently need to increase their doses (sometimes by as much as 50%) during the later half of their pregnancy. This is not due to the increased body weight per se, but rather due to an expanded "volume of distribution", that includes: the placenta, amniotic fluid, and other factors. TSH levels should be obtained each and every month during the pregnancy. Although it is not necessary to keep the TSH suppressed during the pregnancy, anytime the TSH rises to 2.0 or higher, the dosage of levothyroxine should be increased appropriately. I tell my patients to work with their obstetrician to make certain that the TSH is drawn each month and that the patient is told of the result, only contacting me if the TSH is at 2.0 or higher for a dosage change.
After delivery, the levothyroxine dosage generally needs to be reduced to the pre-pregnant dosage, even if the excess body weight from the pregnancy persists. It is best to wait at least 5 weeks (6—8 weeks are optimal) after making any alteration in the levothyroxine dosage before checking the free T4 and TSH levels for verification.
—ThyroidCancerHelp, January, 2008
Levothyroxine for scans/therapies (waiting six weeks off)
ALL levothyroxine pills of EVERY BRAND, including all generics, have the same half-life of 7 days. This means that when you stop your pills, after one week, the level of thyroid hormone has fallen to 50% of where it had been. After another week, it is 50% of the 50% (or rather 25% of the original level). Likewise, after a third week, it is 50% of 25% (or rather 12.5% of the original level). In this fashion, it typically takes 6 weeks to be rid of most of the thyroid hormone. For the first 4 weeks of this time, my patients are taking Cytomel (liothyronine) 25 micrograms twice daily, so that they feel well. For the last 2 weeks of the 6-week preparation, they are off ALL thyroid hormones and are instructed not to drive motorized vehicles or to perform dangerous tasks that require full mental concentration.
My schedule averages 6 patients getting hypothyroid-prepped whole body scans, 5 patients getting Thyrogen-prepped whole body scans, and 1 or 2 patients getting full dosimetry studies every week. We need to schedule around 50 patients every month and such schedules are made from 2 to 12 months in advance. In very small thyroid cancer practices there are usually only a few hypothyroid scan patients per month and it is possible to check weekly TSH levels, after the first month, to see if there are unique patients whose TSH levels have risen above 30 earlier than the typical 6 weeks. In my own practice, to do this would be a logistic nightmare and impossible to arrange. This "6-week rule" is a practical consequence of the usual pharmacokinetics of levothyroxine.
—ThyroidCancerHelp, July, 2007
Levothyroxine preparations (composition of)
Levothyroxine tablets (as Synthroid®) contain the following: synthetic crystalline
L-3,3',5,5'-tetraiodothyronine sodium salt [levothyroxine (T 4 ) sodium and the inactive fillers: acacia, confectioner’s sugar (contains corn starch), lactose monohydrate, magnesium stearate, povidone, and talc. The following are the color additives by tablet strength: Strength (mcg) / Color additive(s)
25 / FD andC Yellow No. 6 Aluminum Lake
50 / None
75 / FD andC Red No. 40 Aluminum Lake, FD andC Blue No. 2 Aluminum Lake
88 / FD andC Blue No. 1 Aluminum Lake, FD andC Yellow No. 6, Aluminum Lake, D andC Yellow, No. 10 Aluminum Lake
100 / D andC Yellow No. 10 Aluminum Lake, FD andC Yellow No. 6 Aluminum Lake
112 / D andC Red No. 27 and 30 Aluminum Lake
125 / FD andC Yellow No. 6 Aluminum Lake, FD andC Red No. 40 Aluminum Lake, FD andC Blue No. 1 Aluminum Lake
137 / FD andC Blue No. 1 Aluminum Lake
150 / FD andC Blue No. 2 Aluminum Lake
175 / FD andC Blue No. 1 Aluminum Lake, D andC Red No. 27 and 30 Aluminum Lake
200 / FD andC Red No. 40 Aluminum Lake
300 / D andC Yellow No. 10 Aluminum Lake, FD andC Yellow No. 6 Aluminum Lake, FD andC Blue No. 1 Aluminum Lake
—ThyroidCancerHelp, October, 2007
Levothyroxine, resuming after radioiodine therapy
I advise patients to terminate the low iodine diet at just over 24 hours after the administration of the I-131 therapy dose, the same time that I resume their levothyroxine therapy. Most of the critical re uptake and re-circulation of I-131 from the bloodstream to thyroid cancer cells in completed within the first 24 hours of dose administration. Thus there is no advantage to maintaining the same degree of hypothyroidism or low iodine diet status for more than one day after treatment. Any uptake seen in the post-therapy scan is consequent to tumor uptake from the first day of treatment and will not be affected despite resuming levothyroxine and a normal diet. In addition, even when the full levothyroxine dose is taken, it requires another week before the TSH becomes appreciably lower and a full 4 weeks before it starts to suppress.
Although other physicians may do differently, it is unlikely that they have carefully evaluated the radiokinetics of I-131 in the body.
—ThyroidCancerHelp, July, 2007
Levothyroxine suppression (no significant risk of) to cause osteoporosis
There have been a number of studies performed to evaluate whether suppressive doses of levothyroxine used to treat thyroid cancer can increase the risk of osteoporosis. Some of the studies are well done and many are not. One of the better studies is:
Reverter, J. L., S. Holgado, et al. (2005). "Lack of deleterious effect on bone mineral density of long-term thyroxine suppressive therapy for differentiated thyroid carcinoma." Endocr Relat Cancer 12(4): 973-81.
ABSTRACT: The effect of subclinical hyperthyroidism on bone mineral density is controversial and could be significant in patients with differentiated thyroid carcinoma who receive suppressive doses of levothyroxine (LT4). To ascertain whether prolonged treatment with LT4 to suppress thyrotropin had a deleterious effect on bone mineral density and/or calcium metabolism in patients thyroidectomized for differentiated thyroid cancer we have performed a cross-sectional study in a group of 88 women (mean +/- SD age: 51 +/- 12 years) treated with LT4 after near-total thyroidectomy and in a control group of 88 healthy women (51 +/- 11 years) matched for body mass index and menopausal status. We determined calcium metabolism parameters, bone turnover marker N-telopeptide and bone mass density by dual-energy X-ray absorptiometry. No differences were found between patients and controls in calcium metabolism parameters or N telopeptide except for PTH, which was significantly increased in controls. No differences were found between groups in bone mineral density in femoral neck (0.971 +/- 0.148 gr/cm(2) vs 0.956 +/- 0.130 gr/cm(2) in patients and controls respectively, P = 0.5). In lumbar spine, bone mineral density values were lower in controls than in patients (1.058 +/- 0.329 gr/cm(2) vs 1.155 +/- 0.224 gr/cm(2) respectively, P < 0.05). When premenopausal (n = 44) and postmenopausal (n = 44) patients were compared with their respective controls, bone mineral density was similar both in femoral neck and lumbar spine. The proportion of women with normal bone mass density, osteopenia and osteoporosis in patient and control groups was similar in pre- and postmenopausal women. In conclusion, long-term suppressive LT4 treatment does not appear to affect skeletal integrity in women with differentiated thyroid carcinoma.
There are some studies that suggest that there might be some increased risk for osteoporosis in post-menopausal women receiving suppressive levothyroxine therapy; however, this increased risk is likely very small (if present) and is likely mitigated by estrogen therapy.
—ThyroidCancerHelp, August, 2007
Levothyroxine suppression therapy and liver enzymes
Although appropriate adjustment of the levothyroxine dosage, to keep the TSH suppressed to under 0.1 with the smallest dose possible, is not typically associated with changes in liver enzymes, sometimes there is a slight elevation of some of the transaminases (including ALT). The most common enzyme to be elevated is a slight elevation of Alkaline Phosphatase.
On the other hand, sometimes primary liver disease can cause independent elevations of liver enzymes, sometimes starting low and increasing with time. For that reason, it is very reasonable for a physician, noting a slight elevation, to want to check these tests later on to make sure that the elevation is still minimal or transient, rather than much higher and demonstrating hepatitis.
—ThyroidCancerHelp, October, 2007
Levothyroxine suppression therapy and menopause (titrating)
Sometimes, despite careful adjustment of the levothyroxine dosage so that the TSH is under 0.1 using the minimal dosage that will do so, one still has mild thyrotoxic symptoms. If so, then a beta blocker will often prove very helpful. Sometimes, the symptoms have nothing to do with the thyroid hormone and instead are consequent to coincident menopausal symptoms. Careful consideration of these factors usually permits a resolution to such symptoms.
—ThyroidCancerHelp, September, 2007
Levothyroxine: the reason for the brand-name
In the United States, generic levothyroxine preparations are fine for treatment of hypothyroidism. The problem is that there are several different companies that make this generic and if a generic levothyroxine is prescribed, the particular generic is randomly switched from company to company based on the "price of the day." Although most levothyroxine pills are consistent within the same brand or company's product, they are not the same between brands or companies. That is: Sandoz levothyroxine 150 mcg is not equal to Synthroid 150 mcg is not equal to Levoxyl 150 mcg is not equal to Unithyroid 150 mcg is not equal to Levothyroid 150 mcg is not equal to nameless generic 150 mcg.
The differences are usually small and of no concern to people with simple hypothyroidism. On the other hand, in order to take the precise dosage that suppresses the TSH <0.1 without causing thyrotoxic symptoms, the change between different brands or companies is too much of a difference to rely on the adequacy of the dosage. Since it is not possible to compel or prescribe a specific company's generic be used at each pharmacy refill, the only way that one can be sure that the refill will be the exact same dosage and content of levothyroxine is to use a "brand name" drug. It doesn't matter which one, as long as it is the same one each time.
Pharmacies can be a big problem. They have a tendency to try to substitute generics, even when the prescription is clear that it is not permitted. This is because they make a greater profit with generic levothyroxine than with brand name pills. The only way to be certain that you have the correct pills is to open the bottle at the pharmacy counter and check the pill itself, noting the brand name and dosage (usually written right on the pill).
—ThyroidCancerHelp, June, 2007
Liothyronine (T3) therapy, temporary
Under extenuating circumstances, Cytomel (liothyronine or T3) can be taken for a few weeks to restore reasonable thyroid status for surgical procedures; however it should be given in divided doses (2 or 3 times daily) and averaging a total of 50 micrograms per day. Stable treatment with levothyroxine should be initiated as soon as appropriate.
—ThyroidCancerHelp, October, 2007
Lithium for radioactive iodine therapy (the use of)
There is a small subset of thyroid cancer patients with metastatic tumors that appear to be resistant to the effects of radioactive iodine, despite evidence that the tumor takes up the radioactive iodine, because the tumor cells are unable to hold on to the radioactive iodine long enough for the radiation to affect the cells. In these situations, lithium carbonate, administered for 2 to 3 days before the radioactive iodine treatment and continued for 5 days after the treatment, appears to prevent the radioactive iodine from leaving the cells so quickly. This appears to enhance the effects of the treatment. This is not used for every radioactive iodine therapy, but only when the disease appears particularly aggressive or resistant to therapy.
—ThyroidCancerHelp, August, 2007
Lithium to enhance radioiodine (a primer on using)
Now that I'm asked, here is a "primer" on lithium use.
Only a portion of patients with thyroid cancer have rapid turnover of I-131 in their tumor. It is my practice to do a 24 hour and a 48 hour whole body scan after the administration of the I-131 tracer dose. This permits me to see if the tumor sites are rapidly discharging their I-131 and would require lithium to enhance the therapy. Sometimes, if previous treatments have been unsuccessful, I both increase the administered dose of I-131 and give lithium carbonate for the next I-131 treatment.
I do not routinely use lithium carbonate on ALL patients because: 1) hypothyroid patients often have nausea due to delayed gastric emptying and lithium can aggravate nausea; 2) there is a very narrow interval between adequate blood levels of lithium and toxic blood levels of lithium, requiring the dosage of lithium to be carefully adjusted for at least 3 days before the I-131 is given, with measurements of the lithium level in the blood; and 3) when lithium is used for this purpose, it must be started 3 days before treatment and continued for 5 days after treatment to get the appropriate possible benefit. On the other hand, I do not hesitate to use lithium in the appropriate circumstances and with careful preparation of my patients and documentation of its benefit with post-therapy whole body scans at 48 hours and again (usually) at 4-5 days.
I was part of the team of researchers that early characterized its use [Koong SS, Reynolds JC, Movius EG, Keenan AM, Ain KB, Lakshmanan MC, Robbins JR 1999 Lithium as a potential adjuvant to 131I therapy of metastatic, well differentiated thyroid carcinoma. J Clin Endocrinol Metab 84(3):912-916]. There are a number of features that are important to know, if it's to be used.
Purpose: to enhance the retention of radioactive iodine in thyroid cancer tissue that is unable to hold on to it for very long. The effective half-life of retention of radioiodine in therapeutically-responsive thyroid cancer is usually 5-6 days. Lithium may enhance this retention in those selected tumors with much shorter half-lives; but has no beneficial effect on thyroid cancer with normal half-lives of retention. Lithium does not enhance uptake of iodine and cannot convert tumors, which do not take up iodine into tumors that do.
Method of administration: The key is to have an effective serum level of lithium at the time of administration of the radioactive iodine therapy. This is achieved by administering an oral bolus dose of lithium (lithium carbonate) at midnight, 2 days before the treatment day, followed by an oral dose every 8 hours (8 AM, 4 PM, midnight). On the morning of admission, I obtain a trough serum lithium level (just before the 8 AM dose) and adjust the lithium dosing to bring the serum level into the range of 0.6 — 1.2 mEq/L. At this point, the radioactive iodine
therapy is administered. The lithium is continued for a total of 5 days from the time of radioactive iodine administration (in order to permit the half-life to become prolonged to the maximal 5 day level). There is no value in giving lithium earlier nor longer than outlined above.
Side effects: Acute administration of lithium may enhance sensations of nausea or gastric upset. This is of particular concern when attempting to prevent loss of the swallowed radioiodine dose. Any lithium level above the 1.2 mEq/L level can be associated with additional and worse side effects, making it very important to keep the level correctly adjusted. This is also a good reason to avoid prolonged administration of lithium longer than warranted for its intended purpose.
—ThyroidCancerHelp, September, 2007
Lithium will not alter thyroid hormone levels in patients taking levothyroxine
Lithium is sometimes used temporarily as an aid to high dose radioiodine therapy; however, this particular question is about a totally different aspect.
Lithium is otherwise used for some mood disorders. When it is used in people with thyroid glands, particularly those with underlying cases of Hashimoto's thyroiditis, it can contribute to cause hypothyroidism.
When lithium is used in people who have had their thyroid glands removed, such as for thyroid cancer, and who take levothyroxine medication to provide their thyroid hormone, lithium has NO EFFECT on their thyroid hormone status.
There can be very rare effects of lithium on parathyroid glands (causing calcium levels to rise), and it is very important to check the blood levels of lithium to make sure that the right dose is taken.
—ThyroidCancerHelp, July, 2007
Lovastatin and levothyroxine
There is a single case report in the medical literature in 1989 of lovastatin treatment associated with need for increased dosage of levothyroxine, but the mechanism of this effect is not known and it seems to be quite out of the ordinary. I have many patients treated with both of these drugs who do not show such an effect. Thus, it's possible that there is an interaction of levothyroxine and lovastatin that results in a need to increase the levothyroxine dosage, but this is uncommon and should not be presumed.
—ThyroidCancerHelp, December, 2007
Low iodine diet and beans (okay to eat)
I am the original source of the low iodine diet to the ThyCa organization a dozen years ago. Unfortunately, members of that organization have adulterated the diet, incorporating inappropriate additional restrictions from a number of sources that are not correct. The Low Iodine diet, as presented in Norene Gilletz's The Low Iodine Diet Cookbook www.lidcookbook.com is accurate and effective. I've verified this diet over the past two decades with 24 hour urine iodine studies in many patients.
There is NO reason for restrictions on ANY types of beans. Any communications to the contrary are wrong. A low iodine diet is not a venue for creative restrictions from the imagination. It's an important part of thyroid cancer management. The current ThyCa diet is generally fine, but has unnecessary restrictions (certain kinds of rice, no potato skins, certain kinds of beans, etc.) that are wrong and unhelpful. Likewise, although the National Institutes of Health expounded a reasonable low iodine diet two decades ago, none of the dieticians who devised the diet at that time are still employed at the NIH and their current diet is quite inaccurate with a number of wrong recommendations.
—ThyroidCancerHelp, December, 2007
Low iodine diet and dark chocolate
For the low iodine diet cocoa butter is fine. It comes from beans not mammary glands. Please enjoy your dark chocolate that doesn't have milk or salt.
—ThyroidCancerHelp, October, 2007
Low iodine diet and vitamins (DO NOT use ANY multivitamins on a LID)
I do not advise using ANY multivitamins when on the low iodine diet, regardless of whether they are on any list as being low iodine compatible.
This if for the following reasons:
1. There is no possibility of any ill health consequences from missing a multivitamin supplement for the very limited 2-3 weeks that someone is on a low iodine diet.
2. A properly prepared low iodine diet is not deficient in any known vitamins or minerals (except iodine) and there is no possible need for additional supplementation
3. Vitamin companies regularly change the composition of their vitamin mixtures, usually with no notification. I've found, over the years, that some vitamins that were free of iodine at one time are now fully containing iodine a few years later.
4. The list of ingredients on vitamin bottles are long, in small type, and difficult to read. It is
very, very easy to miss iodine when it is listed as one of 30+ ingredients.
5. A mistake of taking even a single iodine-containing vitamin pill while on a low iodine diet will total OBLITERATE the diet, as if it were never even attempted. This is because the usual content of iodine in a vitamin pill is 150 mcg, 3 times higher than the total daily iodine content of a properly performed diet.
—ThyroidCancerHelp, September, 2007
Low iodine diet basics
The low iodine diet is based on basic instructions the I provided to ThyCa more than a decade ago and were originally derived from a basic diet formulated at the NIH in the 1980's. Following the diet accurately is sufficient; however, recipes (such as in The Low Iodine Diet Cookbook by Norene Gilletz) make it easier to follow.
REPOSTING OF ORIGINAL LOW IODINE DIET: LOW-IODINE DIET DIRECTIONS: (USED FOR PREPARATION FOR RADIOIODINE SCAN OR THERAPY)
Avoid the following foods, starting when instructed prior to your radioactive iodine test, and continue until after your radioactive iodine treatment is completed:
1. Iodized salt, sea salt (Non-iodized salt may be used).
2. Dairy products (milk, cheese, cream, yogurt, ice cream, butter)
3. Eggs (most of the iodine is in the yolk; egg whites are fine)
4. Seafood (fish, shellfish, seaweed, kelp)
5. Foods that contain the additives: carragen, agar-agar, algin, alginates
6. Cured and corned foods (ham, corned beef, sauerkraut)
7. Bread products that contain iodate dough conditioners (sometimes, small bakery breads are safe)
8. Foods and medications that contain red food dyes (specifically, Red Dye # 3 (erythrosine); consult your doctor before discontinuing any red-colored medicines)
9. Chocolate (for its milk content)
10. Molasses
11. Soy products (soy sauce, soy milk)
Additional Guidelines
1. Avoid restaurant foods since there is no reasonable way to determine which restaurants use iodized salt.
2. Plain Matzos can be used instead of bread.
3. Non-iodized salt may be used as desired.
4. Read ingredients lists of prepared or packaged foods carefully.
5. Avoid taking multivitamins, since most contain iodine.
6. Olive oil may be used as a condiment or in cooking, in place of butter.
7. It is helpful to prepare low-iodine meals in advance and freeze them for easy use when on the diet.
Important Note
Food prepared from any fresh or frozen meats, fresh or frozen poultry (avoid broth-injected poultry), fresh or frozen vegetables, and fresh fruits should be fine for this diet, provided that you do not add any of the ingredients listed above to avoid. The diet is easiest when food is prepared from basic ingredients.
Strict adherence to this diet will significantly enhance the sensitivity of the radioiodine scans and the effectiveness of any radioiodine treatments.
—ThyroidCancerHelp, August, 2007
Low iodine diet (effectiveness of)
The low iodine diet is not much of a mystery. It is based upon sound and basic principles of radiobiology and physics. In fact, the entire field of radiation protection against nuclear fallout or accidents is based upon the same principles in reverse, giving high doses of non-radioactive iodine to protect people's thyroid glands from absorbing radioactive iodine. The efficacy of this principle was proven during the Chernobyl accident in 1986 by the country of Poland, preventing thyroid cancers by dispensing non-radioactive iodine to their own citizens. Neighboring children in Belarus, without such protection, suffered astronomical increases in thyroid cancer.
As far as the low iodine diet, the best study to date is quoted below:
Pluijmen, M. J., C. Eustatia-Rutten, et al. (2003). "Effects of low-iodide diet on postsurgical radioiodide ablation therapy in patients with differentiated thyroid carcinoma." Clin Endocrinol (Oxf) 58(4): 428-35. OBJECTIVE: Most patients with differentiated thyroid carcinoma (DTC) undergo total thyroidectomy followed by routine radioiodide thyroid remnant ablation. Most centers that routinely perform radioiodide ablation prescribe a low-iodide diet (LID) to increase the radioiodide accumulation in thyroid remnants. The efficacy of an LID on thyroid remnant ablation, however, has never been demonstrated convincingly. DESIGN AND METHODS: In a retrospective study, we studied two groups of DTC patients without distant metastases, who had received either a standard diet or an LID during ablation (LID group, n = 59, and control group, n = 61). Both groups were compared for radioiodide uptake in thyroid remnants during ablation and efficacy parameters of remnant ablation, 6 months after ablation. A subgroup without extrathyroidal tumor growth was analyzed separately (stages T1-3, N0). RESULTS: In the total group, the LID during ablation decreased the 24-h urinary iodide excretion to 26.6 micro g compared with 158.8 micro g in controls whereas radioiodide uptake in thyroid remnants was increased by 65% (P < 0.001). Six months after ablation, patients were investigated after thyroid hormone withdrawal. In the total group, no significant effects of the LID during ablation were observed on thyroglobulin (Tg) or the percentage of patients with persistent neck activity after 185 MBq 131I. However, in the LID group, 65% of patients without Tg antibodies had undergone successful ablation (defined by absent neck activity and Tg < 2 micro g/l) compared with 48% in the control group (P < 0.001). In the subgroup (T1-3, N0), 8% of the patients who had undergone the LID had Tg >/= 2 micro g/l vs. 32% in the control group (P = 0.012), whereas successful ablation was achieved in 71% of patients without Tg antibodies in the LID vs. 45% in the control group (P < 0.001). CONCLUSION: We conclude from this study that a low-iodide diet during thyroid remnant ablation improves the efficacy of this treatment.
No one has had the time nor opportunity to look at long-term outcomes based upon using the low iodine diet because to study this would require 20 years of time, large numbers of patients and study personnel, and literally millions of dollars. Any contributions for that cause?
—ThyroidCancerHelp, August, 2007
Low iodine diet (medications on the)
Most oral medications are fine on the diet, as long as they don't contain Red dye #3 or iodine. The only way to determine this is to read the package ingredients, or the package insert. If the medication is a prescription item, ingredients are usually listed in the PDR. Alternatively, a pharmacist may be asked. Most pharmacists do not know what contains iodine, but they can tell you if Red Dye #3 is present.
Strangely enough, calcitriol (Rocaltrol®) in the 0.5 mcg capsule size contains Red Dye #3 (erythrosine). Fortunately, the 0.25 mcg capsule of the same medication is free of this dye and can be substituted (use two of them to equal a 0.5 mcg dosage) during a low iodine diet. This medication is frequently used for thyroid cancer patients who have hypoparathyroidism.
—ThyroidCancerHelp, August, 2007
Low iodine diet myth of “controversy”
In regards to other physicians expressing their disbelief in use of the low iodine diet or questioning its value, I have only one thing to say. They are completely wrong. Their ignorance of this issue is unfortunate, but not my concern. This site provides accurate information to people with thyroid cancer who are interested in such knowledge. Members can choose their own diet for appropriate circumstances. The only controversy that exists about the low iodine diet is between physicians who are untrained and ignorant regarding radiobiology and thyroid oncology. Among thyroid cancer experts, there is no controversy.
—ThyroidCancerHelp, December, 2007
Low iodine diet (no milk or butter)
Please do not seek the answer to iodine content of butter. It can vary by 10-fold depending on the source of the milk used to make butter. A low iodine diet is NOT a low iodine diet if it has ANY butter.
My infamous statement on milk is: For the Low Iodine Diet: DO NOT use ANY milk from ANY mammal in ANY form. It doesn't matter if it is cow, goat, dog, whale, human, cat, pig, giraffe, monkey, hippopotamus, prairie dog, dolphin, or muskrat. It doesn't matter if it is fresh, fermented, powdered, frozen, shaken, stirred, dried, diluted, or coagulated. It doesn't matter if it is yogurt, cheese, ice cream, skim, whole, cream, or butter.
Glandular breast tissue of female mammals is able to transport and concentrate iodine from the bloodstream of the animal and excrete milk with relatively higher iodine content. One could see how important this source of iodine would be for infant animals who depend on this iodine source for their own production of thyroid hormone. On top of all of this, commercial dairies use iodine-containing liquids to clean the teats of dairy animals. Similar liquids are used to clean the myriad tubing of milking equipment. All of these natural and unnatural processes add to the high iodine content of all MILK and MILK PRODUCTS.
—ThyroidCancerHelp, August, 2007
Low iodine diet: no need to prolong it
Some people think there is a value to prolonging the LID. There is no value to extending the low iodine diet. There is no such thing as "conditioning" thyroid cancer cells to take up iodine. The ability of these cells to take up iodine depends upon their ability to make the sodium/iodide symporter (NIS), the "iodine pump protein", place NIS in adequate amounts in the cell membrane, and the ability to organify ("hold on to") the transported radioactive iodine so that it remains in the cell long enough irradiate the DNA of the cancer cell. The issue is that NIS transports radioactive iodine and non-radioactive (stable) iodine equally. If the amount of stable iodine is excessive, compared to radioactive iodine, only the stable iodine will go into the thyroid cancer cells; resulting in no therapeutic benefit. After CT contrast dye administration, the amount of stable iodine exceeds the typical amount of radioactive iodine used for therapy by more than one million-fold. This is the problem. The only solution is to wait out the bodies natural removal of the CT dye stable iodine before giving a therapy. The low iodine diet will not affect this at all; merely preventing additional stable iodine from the food and drink that one is ingesting.
—ThyroidCancerHelp, February, 2008
Low iodine diet: not every LID is an accurate one
It is a sad reality that not all "low iodine diets" from all physicians or institutions are truly low iodine diets. The low iodine diet from the National Institutes of Health has been altered over the past decade in such a way that it is no longer reliable. Their allowance of butter is an example of their diet's current shortcomings.
The diet listed on the ThyCa website was originally provided by me at least a decade ago, yet the recipe exchange on their website is not entirely accurate, by virtue of adding additional restrictions that are not appropriate (for example, potato skins).
The diet that is described in Norene Gilletz's cookbook, "The Low Iodine Diet Cookbook" is entirely accurate and has been verified in my patients by measuring 24 hour urine iodide studies while on the diet www.lidcookbook.com.
—ThyroidCancerHelp, August, 2007
Low-level radiation exposure and risk for thyroid cancer
Adult exposure to ionizing radiation is not as likely to predispose to thyroid cancer as when children are exposed. In addition, the specific exposure of thyroid cells from radioactive iodine nuclear fallout is very different from the exposure to low-level incidental x-rays. The greater intensity of external beam radiotherapy, such as for now-debunked thymus irradiation of infants or for treatment of lymphomas is much more likely to cause such risk. Diagnostic x-rays are of too minimal intensity to contribute to this risk. Although there is no definitive way to totally exclude a contribution of long-term low-level radiation exposure (such as seen when guarding nuclear material) from thyroid oncogenesis, it is unlikely to be much of a factor.
—ThyroidCancerHelp, September, 2007
“Low risk” what does it mean?
The definition of "low risk," sufficient to avoid radioactive iodine treatment is not carved in stone. It varies widely between different physician's opinions. Many of the patients that others consider to be sufficiently low risk, I find not appropriate to be in that category.
If a person is truly of sufficient "low risk" to not require radioactive iodine ablation, it is not considered necessary to perform I-131 scans, since there is no intention to put that person through the full scan preparation and no intention to give treatment.
As stated many times before, the only patients that I consider "low risk" sufficient as to avoid I-131 ablation therapy are those individuals with a SINGLE focus of typical papillary thyroid cancer completely contained within the gland that is under 1.0 centimeters in diameter and is NOT associated with any known metastatic lymph nodes or any evidence of disease outside of the thyroid gland. If someone has ANYTHING ELSE, even if designated by their own physicians as "low risk," I would be inclined to proceed with radioiodine scans and ablation.
—ThyroidCancerHelp, January, 2008
Low thyroglobulin levels (the meaning of)
As far as thyroglobulin levels, please note that there is a difference between a stimulated thyroglobulin level that is considered "clinically negative" and one that is "biologically negative". Ten years ago, the most sensitive thyroglobulin assay could measure down to 2 ng/mL. Currently, the most sensitive assay in clinical use measures down to 0.1 ng/mL. Patients that had TG levels under 2 would not have been treated for residual disease (on the basis of the TG level alone) 10 years ago; however, now we consider a TG over 0.4 ng/mL to be positive. Nothing has changed except the assay sensitivity and our clinical practice. On the other hand, although "biologically" ANY thyroglobulin indicates residual thyroid cancer cells, (even a level of 0.1 ng/mL) we do not consider such low levels to be "clinically" significant and warranting radioiodine therapy.
Please remember, "biologically" nearly all thyroid cancer patients who live their entire lifespan and die of old age probably have a few residual thyroid cancer cells that never revealed themselves during their lifetime. Don't ever fool yourself to think that an undetectable thyroglobulin level means that you're "cured." That's why thyroid cancers need to be followed for the rest of your life.
—ThyroidCancerHelp, August, 2007
Lung metastases (approach to)
Although my patients range in age from 7 years old to 102 years old, both men and women, including every type of thyroid cancer ever heard of (from micropapillary cancers to sclerosing mucoepidermoid carcinoma with eosinophilia), I tend to have a much higher number of patients with lung metastases than most other physicians. This is because I am sent such patients by other physicians, sometimes for the purpose of high-dose dosimetry-limited radioactive iodine therapy, sometimes for one of our experimental protocols for aggressive tumors.
When patients with lung metastases no longer respond to radioactive iodine, despite optimal preparation and dosing, its important to take stock. The important things to do are to make certain that TSH is well suppressed under 0.1, keep careful track of tumor volumes using CT scans, and make certain that tumor metastases are not growing undetected in critical sites, such as the brain or spinal cord. Should critical tumor sites be found, they should be dealt with by surgical resection followed by external beam radiotherapy (if applicable).
For metastases in soft tissue organs, such as the lungs and liver, it is important to monitor the rate of progression as assessed by CT scan measurements of tumor volumes. I have many patients whose tumors have remained stable in size and number for many years, sometimes even for a decade. On the other hand, at any time such tumors may suddenly alter their growth rate and take off. When that happens, it means that it is a dangerous time and that tumors are actively growing, spreading, and likely to significantly diminish the quality and length of life fairly soon.
Most of my clinical research trials are aimed towards this group of patients with rapidly progressive, unresponsive, and distantly metastatic tumors. Fortunately, we've been having great success with our current research trial using lenalidomide (Revlimid).
—ThyroidCancerHelp, August, 2007
Lung nodules need to be carefully evaluated
The production of thyroglobulin by thyroid cancer cells and the ability of these cells to take up radioactive iodine are functional properties of these cells that can be lost. Certainly, there are some thyroid cancers that do not take up radioiodine and also there are some thyroid cancers that fail to make any thyroglobulin. Both properties may be lost in the same cancer cells, or they may be lost independent of each other. Knowing this, it is certainly possible that a nodule in the lung may represent thyroid cancer that has spread there, despite no elevation in the thyroglobulin level and absence of radioactive iodine uptake at that site on a whole body scan.
On the other hand, it is not a good idea to have tunnel vision. People with thyroid cancer may also develop other cancers. People with thyroid cancer who are smokers, have the same risk of developing a lung cancer as do smokers without thyroid cancer. Likewise, I've had patients with thyroid cancer whose lung nodules came from metastatic breast cancer. It is very important to have any significant lung nodules evaluated with a biopsy, particularly if clinical features are unusual (such as lack of thyroglobulin elevation) for thyroid cancer.
All clinical staging systems are generally irrelevant with regards to individual people. They are best suited for making predictions on large populations of patients and have little value for individual patients. When tumors invade through the thyroid capsule into the soft tissues of the neck, they have a higher risk of spreading to distant sites (such as lung, liver, bone, etc) than tumors that were confined to the interior of the thyroid gland.
—ThyroidCancerHelp, July, 2007
Lymph node concern (enlarged neck)
Papillary thyroid carcinomas of clinical significance, including multifocal papillary microcarcinomas, are very commonly noted to spread to local lymph nodes in the neck. The assessment of the neck for metastatic disease in lymph nodes is based on the combination of the stimulated (with hypothyroidism or Thyrogen) thyroglobulin, the results of properly prepared I-131 whole body scans, and anatomical assessments ( such as using neck ultrasound). The features seen on I-131 are typically quite specific for thyroid cancer metastases. The elevation of the thyroglobulin in the blood is very specific for persistent thyroid cancer somewhere in the body. The findings of enlarged lymph nodes on ultrasound is only suggestive of possible local metastases and the specific features seen on these ultrasounds is not diagnostic of this cancer, only suggestive. When a fine needle biopsy is performed with the ultrasound, any evidence of thyroid-derived cells in these nodes becomes very specific for demonstrating thyroid cancer. On the other hand, if a well-performed biopsy reveals adequate cellular samples that do not contain thyroid cancer, only normal lymphocytes, then this negative finding must be evaluated using the full context of the informative studies listed above. If there is a high index of suspicion (elevated thyroglobulin, documented continuing enlargement of the lymph nodes) then it may be an appropriate judgment to do a surgical assessment. The appropriateness of such a decision is only able to be determined by the physicians who have access to the appropriate information and can directly assess the patient.
—ThyroidCancerHelp, September, 2007
Lymph node involvement (significance of profuse)
The appearance and behavior of the thyroid cancer at the time of initial surgery often gives clues as to its future behavior. In that way, profuse local lymph node metastases suggests an enhanced likelihood for further spread and recurrence in lymph nodes. This should be considered as a reason to pay closer attention to this tumor and to be more assertive when selecting treatment options (i.e. low vs. higher dose radioactive iodine; hypothyroid vs. rhTSH preparation, etc).
—ThyroidCancerHelp, September, 2007
Lymph node resection, surgical decisions regarding
There is NO WAY that a surgeon would have knowledge of lymphatic or vascular invasion during the time that they are doing the initial surgery. These pathological features would only be discerned by the pathologist after several days of evaluating the tumor specimen and would not be able to be discerned on "frozen section" (the quick evaluation done by the pathologist during the surgery). Thus, not only do surgeons NOT base their choice of neck dissections during the initial thyroid surgery on these features, they could not do so even if they wanted to. The type of neck dissection that is done at the time of initial thyroid surgery should be based upon the skilled judgement of an expert surgeon and should generally include a central neck dissection and an ipsilateral (same side as the cancer in the gland) neck node resection; however, most thyroid surgeries are not performed by specialist "thyroid surgeons" and the actual surgical approaches vary far more radically than most thyroid oncologists would prefer.
—ThyroidCancerHelp, December, 2007
M
Macroscopic recurrences of thyroid cancer
Radioactive iodine is much less effective in eliminating MACROscopic disease (able to be seen on an ultrasound or Xray study or felt by exam) than MICROscopic disease. For that reason, in general, macroscopic tumor is best removed surgically if it is safely possible, then followed by radioactive iodine therapy (if there is still radioactive iodine uptake) or external beam radiotherapy (if there is no longer any radioactive iodine uptake and it is the proper part of the body for such treatment).
The specific application to any particular situation may be a little more complicated (thus the suggestion for the physician to contact me).
My practice is to always use the same or higher dose of radioactive iodine for subsequent treatments if there is residual tumor that can be seen to take it up. If a particular dose strength doesn't do the job, it makes most sense to use a more powerful dose for the repeat treatment. Of course, specific situations may require different approaches.
—ThyroidCancerHelp, June, 2007
Macroscopic thyroid cancer (recurrent) with negative radioiodine scans
When recurrent tumor is large enough to be seen on anatomical imaging studies and revealed by biopsy, it is considered MACROscopic tumor. Properly performed and prepared I-131 whole body scans (proper elevation of TSH, good low iodine diet, no CT contrast dye contamination, etc.) that are negative in the context of evident macroscopic tumor show that there will not be any value to further radioiodine therapy. Such I-131 treatment for scan-negative, thyroglobulin-positive tumor situations is only valid for presumed MICROmetastatic disease that is not visible nor evident on any anatomical (CT, MRI, ultrasound, x-ray) imaging.
For further information regarding post-operative external beam radiotherapy, please see messages: #93, #384, #813, and #2554.
—ThyroidCancerHelp, March, 2008
Macroscopic tumor is appropriate (resection of)
When there is a macroscopic lymph node metastasis (large enough to be seen on ultrasound) it is usually a good practice to have it surgically removed prior to destroying the residual microscopic disease with radioactive iodine. This appears to be a reasonable approach.
—ThyroidCancerHelp, September, 2007
Median sternotomies and modern techniques
Minimally invasive surgery, utilizing modern fiber optics and operating devices are relatively new. My example of a patient requiring a median sternotomy for removal of her thymus was relating a situation nearly a dozen years ago, when minimally invasive techniques in that region were closer to science fiction. Also, in some instances of invasive tumor or extensive metastatic disease, median sternotomies are still necessary if surgery is appropriate to pursue.
—ThyroidCancerHelp, September, 2007
Medullary thyroid cancer: A primer
Medullary thyroid cancers (MTC) are very different, in most respects, from papillary and follicular cancers. MTC is a malignancy that arises from the parafollicular cells rather than the follicular cells of the thyroid gland (from which arise papillary follicular cancers). Parafollicular cells do not have TSH receptors, do not take up iodine, and do not make thyroglobulin; instead producing calcitonin, somatostatin, somatomedins, and CEA (when malignant). For those reasons, suppression of TSH, use of radioiodine, and use of thyroglobulin testing do not apply at all to MTC.
In addition, one third of MTC cases occur due to a genetic mutation in a specific gene, the RET proto-oncogene, that is inherited within families and requires genetic testing of all new cases in order to uncover family members with the mutation who could have their thyroid glands removed before their MTC develops or spreads.
Lastly, although there are new drugs that can retard the spread and growth of MTC, there are no medications that can reliably destroy MTC (no chemotherapy drugs have yet been found effective to kill MTC cells). For that reason, very careful, complete and aggressive surgery is critical for early management of this cancer (with extensive neck lymph node dissections).
Because of these issues, the following sequence is typically advised in treating new MTC patients:
1) Total thyroidectomy with bilateral and central neck lymph node dissections in an effort to remove all macroscopic disease possible. Before the surgery, if suspected from the thyroid biopsy, it is important that the person be checked for a pheochromocytoma (see below);
2) Blood should be sent to a genetics testing laboratory to check for a mutation in the RET proto-oncogene. If such a mutation is found, a genetics counselor should be employed to supervise the testing of the entire family to detect additional affected individuals. If someone has the mutation, the WILL get the MTC at some time if their thyroid is not removed in advance. Some patients with this mutation may also have the syndrome called Multiple Endocrine Neoplasia (MEN) type 2a or 2b, associated with additional medical problems (pheochromocytoma, an adrenaline-releasing tumor of the adrenal gland, and other problems).
3) Following the thyroid surgery, a complete tumor staging should be done; meaning that CT scans should be performed of the entire body as a baseline evaluation for tumor that may have already spread. For MTC patients, CT scan contrast SHOULD be used since there is no intention to ever use radioactive iodine for any reason.
4) After the thyroid surgery, testing blood for CALCITONIN and for CEA (carcinoembryonic antigen), provides a means for assessing for the presence of disease in the body. Just as thyroglobulin is a "tumor marker" for papillary and follicular thyroid cancers, calcitonin and CEA are tumor makers for MTC.
5) If MTC is found in places in the body during the course of tumor staging, surgery should be performed on isolated metastases, if accessible to surgery. MTC metastases are not very responsive to external beam radiation (XRT) and, although in some cases XRT may be useful, its use remains a point of controversy.
6) For MTC metastases that cannot be dealt with by surgery, sequential CT scans at reasonable intervals should assess for rate of growth (also using calcitonin and CEA levels). Sometimes MTC metastases remain quiescent for prolonged periods of time. If there is evident tumor progression, the patient should consider participation in a clinical trial that is aimed specifically for MTC.
—ThyroidCancerHelp, January, 2008
Menstrual periods and thyroid cancer
Thyroid cancer, by itself, does not typically alter the menstrual periods or cause infertility. The extreme thyroid hormone fluxes that take place when a hypothyroid withdrawal preparation is done for scanning or radioactive iodine therapy may have a
temporary effect on either prolonging or delaying periods or even cause further irregular menses, depending upon the particular person.
On the other hand, radioactive iodine, may affect periods. Although there is no demonstrated effect upon fertility nor any evidence of causing birth defects in subsequent offspring, radioactive iodine therapies certainly give the ovaries some excess
radiation exposure, due to their nearness to the bladder (which would contain a quantity of radioactive urine during a treatment).
In women who are within 5 years of their natural age for menopause, this exposure to radioactive iodine may cause them to go into menopause earlier than they would have otherwise. Even in young women, there is often an effect upon the ovaries that may cause a loss of periods for 2 to 6 months, before they resume in their usual fashion.
—ThyroidCancerHelp, June, 2007
Metastases (treating) to bone
If a "bone cancer" is found on a whole body radioactive iodine scan, then a presume that this is not a bone cancer but rather a thyroid cancer metastatasis to bone. In such cases, radioactive iodine alone is usually insufficient to eliminate the thyroid cancer in the bone (bone metastasis). Bone metastases are best treated by having a surgeon cut out the tumor and then following the surgery with radioactive iodine therapy using high dosages (usually with dosimetry, if available). Sometimes, if the bone metastasis does not take up radioactive iodine, external beam radiation is used after the surgery. Unfortunately, some physicians do not realize that this combination therapy is necessary and fail to effectively treat the tumor despite repetitive doses of radioactive iodine….
The major point is this: radioactive iodine alone WILL NOT generally be effective, by itself, in eliminating thyroid cancer metastases to bones. Only by performing a surgical removal of the bone metastasis, then following the surgery with high dose radioactive iodine therapy will the metastases be effectively treated. It is NOT recommended to keep giving further radioiodine doses for a "look and see" type of approach, because by the time that it is seen that that approach has failed, there has already been considerable radioactive iodine exposure and time for dedifferentiation and loss of radioiodine uptake at the tumor sites.
Most doctors do not suggest the surgery because they have little or no experience with this particular problem and find it difficult to obtain appropriately gifted and oriented surgeons.
For extensive bone metastases, we sometimes have to have the radiologist thread a catheter into the arteries feeding the tumor and inject a substance to block the blood flow to the tumor. This permits the surgery to be performed more safely with minimal blood loss. Of course, since iodinated contrast must be used by the radiologist, it requires a delay in doing the radioactive iodine therapy until after urine iodine tests show that the iodine from the contrast has passed out of the body.
—ThyroidCancerHelp, August, 2007
Mis-reading labs
It is unfortunate that many patients, and many of their physicians also, become totally confused by thyroid laboratory studies and misinterpret the results. For example, physicians often confuse a thyroglobulin antibody level for a thyroglobulin level. This results in a great deal of anxiety and sometimes prompts inappropriate therapies.
Thyroglobulin (TG) is measured as nanograms per milliliter (ng/mL) or as micrograms per Liter (µg/L). Both are equivalent measures. Thyroglobulin ANTIBODIES (TG-Ab) are measured as International Units per milliliter (IU/mL).
The presence of TG-Ab will make the TG measurement appear lower than it actually is and renders it unreliable; however, it does not directly represent persistent thyroid cancer. Sometimes, persistence of TG-Ab more than 2-3 years after treatment of thyroid cancer (even if the TG level is undetectable) suggests that thyroid cancer is still present because it is making TG and continuing to stimulate TG-Ab production. The bottom line is to make certain that you know what results you are seeing.
—ThyroidCancerHelp, August, 2007
Multifocal papillary MICROcarcinomas
The key point about multifocal papillary thyroid cancer is to deal with it effectively by utilizing a total thyroidectomy, radioactive iodine ablation, radioactive iodine scanning and use of thyroglobulin in followup assessment. This is supplemented by appropriate anatomical imaging (CT scans without contrast, neck ultrasound, etc) at appropriate intervals. The summary answer is to take care of multifocal MICROcarcinoma in much the same way that one takes care of unifocal MACROcarcinomas.
[topic continued from another post]
I can say that multifocal papillary microcarcinomas should be dealt with in a similar fashion as macroscopic papillary carcinomas. This entails radioactive iodine ablation after appropriate preparation and long-term follow-up to verify that appropriate endpoints are reached and maintained. These endpoints are: 1) absence of sites of uptake on whole body radioactive iodine scans that indicate persistent disease; 2) undetectable thyroglobulin when stimulated by TSH; 3) absence of anatomical evidence of tumor masses (utilizing radiological techniques); 4) long-term suppression of TSH utilizing appropriate dosages of levothyroxine; and 5) maintenance of excellent general physical and mental health. If a treatment plan does not fulfill these endpoints, then I suggest that the approach be modified to fulfill them.
—ThyroidCancerHelp, September, 2007
Muscle weakness/muscle cramps
Muscle cramps can have a variety of causes. Most of them are not related to the dose of levothyroxine. Cramps are common when people have stopped their levothyroxine long enough to become hypothyroid; however, a properly adjusted levothyroxine dose that suppresses the TSH appropriately should not cause such problems.
Sometimes people get "tunnel vision" and just because they have thyroid cancer they start to believe that ALL symptoms are related to it. The reality is that having thyroid cancer does not relieve anyone of the long list of physical problems that can affect people regardless of whether they have thyroid cancer. Some cause of cramps include: 1) low calcium levels, often resulting from damage to parathyroid glands during thyroid cancer surgery; 2) electrolyte disturbances, such as low potassium or magnesium; 3) circulatory problems in the legs, also known as claudication; 4) spinal cord or nerve root compression from vertebral disc disease; 5) etc., etc. It is VERY IMPORTANT it make certain that such symptoms are fully evaluated and ALL potential causes considered by your physician.
—ThyroidCancerHelp, July, 2007
N
Nasolacrimal duct blockage (more on)
Salivary duct obstruction from thickened saliva is not at all similar to nasolacrimal duct obstruction from radioactive iodine therapy. The tears are not altered in their composition or viscosity. Rather, radioactive iodine is associated with inflammatory changes that can be seen in the portion of the nasolacrimal duct that is near the eye. This can cause narrowing and eventual blockage of tear flow from the eye into the nose, resulting in tears welling out of the eye as if one is crying. It is not likely that any of the suggestions, aside from gentle massage, would be of any utility.
—ThyroidCancerHelp, September, 2007
Neck lumps (evaluating recurrent)
There are many types of "lumps" in the neck. After radioactive iodine, unavoidable damage to salivary glands can thicken the saliva that they release, sometimes blocking the ducts that carry saliva into the mouth and causing the salivary glands (located under the ears and under the lower jaw) to suddenly swell. These are nuisances, usually responding to gentle massage and can be recurrent, but they do not represent recurrent thyroid cancer.
On the other hand, it is not unusual for thyroid cancer to re-grow in the neck after tiny microscopic residual tumor cells divide and become large enough to feel.
The bottom line is that only a careful physical examination by a physician can discern a recurrent thyroid cancer from something that is unrelated to this, such as a swollen salivary gland. Should a neck "lump" be found to be something other than a salivary gland, a simple fine needle biopsy is usually an excellent way to see what it is.
—ThyroidCancerHelp, July, 2007
Neck lymph nodes long after surgery, evaluating
Lymph nodes in the neck can become firm and enlarged in response to inflammatory changes (infection, irritation, etc.) as well as consequent to tumor metastases. For that reason, it is not appropriate to automatically assume that such nodes contain cancer. Anytime such lymph nodes persist and do not spontaneously grow smaller or if they further enlarge, a simple fine needle biopsy will let you know if these nodes are malignant.
—ThyroidCancerHelp, March, 2008
Neck pain/stiffness after surgery
It is not uncommon for there to be neck pain and stiffness after going through thyroid surgery, particularly if many lymph nodes are removed from the neck or if there was a large and invasive tumor. Scarring in the neck and discomfort often causes people to reduce the movement of their neck, resulting in even greater stiffness and pain.
My patients often note some improvement with stretching exercises that are performed on a frequent and regular basis. The best results can be seen when they take up swimming as their regular exercise, since this involves regular movement in all dimensions. After a workout in the pool, a dip in the YMCA hot-tub or heated whirlpool bath permits them to continue to "work-out" the stiffness in their necks. An alternative approach is to learn Tai Chi. Sometimes old fashioned neck exercises work well. No particular method works for everyone, but these methods frequently give good results.
—ThyroidCancerHelp, June, 2007
Neck surgery for recurrent disease (more definitive)
When there is recurrent disease in lymph nodes in the neck, it is usually a good practice for the surgeon to do a more complete lymph node removal, rather than just plucking one or two. This has a better chance of providing a more definitive removal of macroscopic tumor and preparing for a better result with radioiodine treatment (if the tumor is still sucking up iodine) or external beam radiotherapy (if there is no longer any radioiodine uptake).
—ThyroidCancerHelp, October, 2007
NED: no evidence of disease (definition)
Laboratory studies of anti-thyroglobulin (anti-TG) antibodies define a "normal" range that encompasses patients without clinically significant anti-TG antibodies. We don't ever expect a result number to be "0"; however, we expect it to be beneath the upper range of "normal" for us to have better confidence that it is not interfering with the thyroglobulin results.
When my patients have an undetectable thyroglobulin and a clean well-done radioactive iodine scan (with appropriately elevated TSH from the hypothyroid preparation or Thyrogen injection), utilizing a good low iodine diet, I try to corroborate these results with my physical examination. Often we may perform other radiographic procedures to make sure that there aren't any tumor nodules that are seen.
When all of these studies are negative (meaning "clean"), I tell my patients that they have No Evidence of Disease (NED), instead of "cancer-free." That is because none of these tests are sufficiently sensitive and powerful to detect ALL thyroid cancer cells in a person. They all have their limits to their detection abilities. Many patients in this situation, over the course of years or decades, may have sufficient proliferation of small areas of residual disease to cause the tumor to appear to have "recurred". Because of this, thyroid cancer patients should be monitored and evaluated essentially for life. In practical terms, I usually discharge them from my clinic after they pass their first century of life.
—ThyroidCancerHelp, October, 2007
O
Occult papillary cancers
Non-clinical (AKA: "occult") thyroid cancers are typically present in 10 to 60% of the World's population and do not generally require any further treatment once they are discovered in the course of removing all or part of a thyroid gland. They are single, small (typical or follicular variant) papillary carcinomas, less than 1.0 cm in diameter, completely contained within the thyroid gland, not invading through the capsule of the thyroid nor into a blood vessel, and not involving any part of the body outside of the thyroid gland (no local nor distant metastases).
—ThyroidCancerHelp, July, 2007
Octreoscans in thyroid cancer
An Octreoscan is a nuclear imaging study that uses injected radioactive octreotide to try to find tumors. It is not very useful or effective for most thyroid cancers. Octreotide is a medication that is an analog (related compound) of somatostatin (a hormone that is made by a number of cells in the body with a variety of different effects). There are several different receptors (binding sites) for somatostatin that are present in different cells of the body (some in tumors). Unfortunately, my own research (performed more than a dozen years ago) analyzed the types of somatostatin receptors on thyroid cancer cells and found that the specific type of receptor that binds best to octreotide (SSTR2) is NOT expressed by thyroid cancer cells. For this reason, octreotide scans would not be very effective in localizing thyroid cancers. On the other hand, this receptor can be found on some of the white blood cells that sometimes surround such tumors. In those instances, the octreoscan may sometimes be somewhat helpful, but this is not typical and not very reliable. For these reasons, most experienced clinicians do not use octreoscans in evaluating thyroid cancer and our clinical experience with such scans bears this out. Medullary thyroid cancer may sometimes be an exception, since the somatostatin receptors on these cells are different and the scan is somewhat more useful for this particular type of thyroid cancer.
—ThyroidCancerHelp, November, 2007
Oncocytic carcinomas
"Oncocytic" means the same as "HŸrthle cells". HŸrthle cell thyroid cancers are also known by the following names: Askanazy cell cancers, oncocytic cancers, and oxyphilic follicular cancers. There are oxyphilic variants of both papillary thyroid cancers and of follicular thyroid cancers; however, when the diagnosis of HŸrthle cell thyroid cancer is made, it usually refers to an oxyphilic follicular cancer. In the question, above, the pathology report is referring to the oxyphilic variant of papillary carcinoma. Under the microscope, these appear similar to follicular thyroid cancers, except that they tend to retain more reddish stain (when stained with eosin for evaluation) appearing pinkish (eosinophilic), due to their higher cellular content of mitochondria. The classification of a papillary microcarcinoma being subclinical and not needing further therapy is NOT applicable to oxyphilic variants of papillary carcinoma, no matter how small.
These cancers behave much as typical follicular thyroid cancers and the clinical approach to them with I-131 scanning and therapy (as well as thyroid hormone suppression therapy between treatments or scans) is nearly identical. A key difference is that, although possible in any type of papillary or follicular cancer, HŸrthle cell cancers have a higher rate of losing the ability to concentrate iodide. This makes them unable to be detected with I-131 scans or treated with I-131 therapy. In my experience, the majority of HŸrthle cell cancers maintain their responsiveness to I-131; however the loss of this responsiveness is common enough to encourage the application of additional tests to check for residual or metastatic disease. Since I-131 is the only known effective systemic treatment for such cancer, it is very important to make full and complete use of it (usually higher I-131 doses), carefully documenting its failure (if it occurs) before abandoning this modality.
In this respect, I often make certain that thyroglobulin levels are carefully assessed, both when stimulated by hypothyroidism for sensitivity and routinely when on thyroid hormone suppression therapy. In addition, I often make use of additional nuclear studies, at reasonable intervals, which do not depend upon iodide uptake, such as: thallium scans, Sestamibi scans, tetrafosmin scans, 18-FDG PET scans, DMSA scans, etc. These can be complemented by anatomical testing using CAT scans (without contrast), MRI scans (gadolinium contrast permitted), or plain xrays as appropriate for the sites of study. These additional tests can be expensive so it is important to use them sparingly and according to the degree of clinical suspicion. My approach to thyroid cancers which have lost responsiveness to I-131 is documented in a publication: [Ain KB. 2000 Management of undifferentiated thyroid cancer. Baillieres Best Pract Res Clin Endocrinol Metab. 14:615-629].
Unfortunately, the particular nuances of each type of thyroid cancer are not uniformly appreciated in the medical profession. Thus, some patients may be followed or treated in ways that are contrary to my approach. For some patients, it may be valuable to obtain additional consultation.
—ThyroidCancerHelp, August, 2007
P
Papillary cancers (small), neck nodes and pregnancy
Usually, typical papillary thyroid cancers that are single tumors under 1.0 cm in diameter in the thyroid gland, are completely contained within the thyroid gland, and have not spread to any areas (lymph nodes, etc.) outside of the thyroid gland, are treated with thyroid surgery and do not require radioactive iodine therapy or scans. In this case, the word "usually" is accurate in that there are some such cases in which the cancer has spread to local lymph nodes and further treatment is both appropriate and necessary.
In such a case, the presence of enlarging lymph nodes in the neck should be evaluated appropriately to see if these lymph nodes contain thyroid cancer. This can be done with an ultrasound-directed fine needle biopsy. A fine needle biopsy is easily done without significant discomfort and can be performed in a pregnant patient without any risk. It is usually done using ultrasound guidance. Although there are features on ultrasound that may suggest that a lymph node is free of tumor, such features are not so definitive as to rule out the need of a biopsy, particularly if the lymph node is enlarging.
If there is any evidence of thyroid cancer by the fine needle biopsy, it may be dealt with by a thyroid surgeon during certain times of a pregnancy without much risk. Even if such surgery is delayed until after the pregnancy, it is usually not a problem.
One key feature is to plan to bottle-feed the baby after delivery, if there is any significant chance that radioactive iodine scans or therapy might be needed. This is because breast-feeding cannot be done under such circumstances and it takes a bit of time after weaning for the breasts to stop concentrating iodine avidly.
—ThyroidCancerHelp, July, 2007
Papillary cancer (two tiny foci of)
One tumor in a thyroid equals unifocal. More than one (even just two) tumor equals multifocal. Although common sense suggests that two tiny foci of papillary cancer cannot be as risky as many such foci in a gland, it is still clear that the statistics that have shown a single focus to be subclinical cannot apply to two or more such foci.
In my practice and experience, I have seen some patients with multifocal disease, with only two small foci, that were later found to have locally metastatic tumor. Despite this, it is still uncommon for such minimal disease to be clinically aggressive. For that reason, I tend to treat patients in this category with radioactive iodine, unless they are so elderly or sick from other medical problems that they would be unlikely to survive long enough to have the treatment make any clinical difference in their life.
This is my own position, but not one that is universally shared by all physicians who deal with thyroid cancer.
—ThyroidCancerHelp, September, 2007
Papillary microcarcinoma
A single nodule of typical papillary carcinoma less than 1.0 cm in diameter (microcarcinoma) that is within the thyroid gland and not associated with any obvious metastases to lymph nodes or any area outside of the thyroid gland is known as an "occult" or subclinical thyroid cancer. It is usually not the reason for the surgery that found it because it was too small to have prompted such surgery. These thyroid cancers do not typically require any further surgery, nor radioactive iodine scans or treatments. Although most physicians would not treat such a patient (with an intact opposite thyroid lobe) with "suppressive" doses of thyroid hormone, some give a slightly higher than replacement dose (to keep TSH in the lower end of the normal range) so that it is less likely that the remaining thyroid lobe would enlarge further.
There should be NO symptoms associated with such thyroid hormone therapy. Even if such a patient were to be without any thyroid hormone therapy, they would not be expected to become hypothyroid (if the remaining thyroid is essentially normal).
—ThyroidCancerHelp, August, 2007
Papillary microcarcinoma
If a surgeon has removed a single lobe of the thyroid and careful examination by the pathologists has only found a SINGLE focus of papillary thyroid cancer completely contained within that lobe that measures 10 mm or less (1.0 cm or less) in diameter, then this is called a unifocal papillary microcarcinoma. Provided that there is no evidence of thyroid cancer anywhere else in the body (based on standard examination and operative assessment), then there is no need to take out the opposite thyroid lobe. [An exception would be a patient whose thyroid cancer occurred in the context of neck exposure to radiation as a small child.] Typically, I put such patients on sufficient levothyroxine to keep the TSH just under the normal lower limit. Ultrasounds are reasonable methods to assess the remaining lobe at infrequent intervals.
If the thyroid cancer is not papillary (for example a follicular or Hurthle cell cancer), larger than 1.0 cm in diameter, multifocal (more than one tumor nodule), invades through the thyroid capsule into surrounding tissues, or is associated with any evidence of tumor outside of the thyroid gland, then complete removal of the thyroid gland and radioiodine therapy, with scans and long-term follow-up, are most appropriate.
—ThyroidCancerHelp, January, 2008
Papillary Hurthle cell carcinoma with lymphocytic stroma (AKA "Warthin-like tumor" of the thyroid)
This is a tumor that necessitates a total thyroidectomy and radioiodine ablation with long term follow-up. If this is what a biopsy has been interpreted as, it is possible that this is correct or not, but it is very unlikely that the biopsy delineates a benign process. There is nothing to be gained by any further procedure or test short of a thyroidectomy and a careful pathological evaluation of the excised thyroid. Get thee to a surgeon.
—ThyroidCancerHelp, September, 2007
Persistent TG = thyroid cancer and it may not be in the neck
This history warrants careful re-reading of the following posting (now for the 3rd time on this site). Please pay careful attention to common errors #1, 2, and 3.
The presence of measurable thyroglobulin levels, even as low as 2, indicates the presence of persistent thyroid cancer.
There are FOUR common errors made in the followup of thyroid cancer: 1) permitting measurable thyroglobulin to be present without fully searching for the tumor source, 2) presuming that any persistent thyroid cancer MUST be in the neck despite the fact that it can spread to anywhere in the body, 3) presuming that thyroid cancer ALWAYS takes up radioactive iodine. (Sometimes, unfortunately, it loses this ability and will not respond to radioactive iodine for either therapy or scans. Sometimes it is "invisible" to the tracer dose of radioiodine, but able to be "seen" or treated with a larger treatment-level dose), and 4) placing any reliance in the assertions of any surgeon that he/she "got it all." (It requires a mass of at least 2,000,000 thyroid cancer cells in a lump for a surgeon to be able to see it and remove it during surgery. All thyroid cancer tumor masses of 1,000,000 , 100,000 ,10,000 , etc. etc. are too small to be seen by any human (or bionic) surgeon.)
As long as interference from non-radioactive iodine is ruled out, the presence of thyroglobulin in the blood should instigate a full assessment of the entire body using a variety of radiological techniques and sometimes using PET scans. Frequently, even after such efforts, the site of the persistent thyroid cancer remains undiscovered. In such situations, maintaining excellent suppression of the TSH with levothyroxine (keep TSH < 0.1) and maintaining a reasonable schedule (avoid bankruptcy or spending all your life in the CT scanner) of continued studies to search for this tumor is the best course with our current state of knowledge.
—ThyroidCancerHelp, June, 2007
PET/CT fusion studies (contrast used with)
Some facilities administer iodinated contrast as part of the CT study that is performed with the PET scan (fusion study). If the contrast is given orally, it will pass in 2 weeks. If it is given IV, it can potentially persist for 2 to 10 months. There is no need to give IV contrast during such a study. The only item that MUST be give IV is the radioactive sugar (18-FDG).
—ThyroidCancerHelp, September, 2007
PET scans and radioactive iodine scans (difference between)
Please do not be confused between radioactive iodine scans and PET scans.
Radioactive iodine scans measure the ability of thyroid cancer cells (if present) to take up
radioactive iodine. The iodine pumps in each thyroid cancer cell (the sodium-iodide symporters; NIS) are increased and "turned on" by TSH (Thyroid Stimulating Hormone) attaching to the TSH-receptors on these cells. This is the reason why TSH must be increased, either by becoming hypothyroid (thyroid hormone withdrawal) or by being injected with human TSH (Thyrogen¨), and the person be on a low iodine diet (to keep non-radioactive iodine from interfering with the radioactive iodine).
On the other hand, PET (Positron-Emission Tomography) scans use radioactive sugar (F-18 deoxyglucose; FDG), not iodine, to do these studies. They rely upon the likelihood that cancer cells are "hungrier" for sugar than normal cells and will "light up" when the PET scan is performed with FDG. Not all thyroid cancer cells will take up FDG; only those thyroid cancer cells that are growing very rapidly and are thus "hungrier." In fact, portions of the body that are infected or inflamed (irritated) will also take up the FDG and "light up" on the PET scan. Some parts of the body normally take up large amounts of sugar and are normally "lit up" on a PET scan (notably the brain, heart, and kidneys).
Many times, people can have thyroid cancer nodules scattered all over their lungs, yet not see them on the PET scan because the nodules are relatively stable and not growing rapidly. For that reason, having a positive PET scan (done when the radioactive iodine scan is clean yet the thyroglobulin level is elevated) is a two-edged sword; seeing the tumors helps find them, but such tumors are very aggressive and difficult to control. If the PET scan is clean (in the face of an elevated thyroglobulin) then it suggests that the thyroid cancer cells may be quiescent and not growing rapidly, even though we may not be able to find them.
It is not necessary to be hypothyroid to do a PET scan. On the other hand, it has been found that TSH stimulation can increase the activity of "glucose pumps" on thyroid cancer cells and make the PET scan more sensitive. For that reason, we often use Thyrogen injections before a PET scan to make it more sensitive. It is not necessary to go on a low iodine diet for a PET scan.
—ThyroidCancerHelp, June, 2007
Physicians and approaches
It is very difficult when you are a patient and the physicians that are available to you don't seem to have sufficient understanding of your disease. This difficulty becomes apparent only when you start to become educated about thyroid cancer sufficiently to start to question your physician's approach. Until 2000, there were very few physicians (including endocrinologists, oncologists, radiation medicine physicians, and many nuclear medicine physicians) who had any specific expertise regarding thyroid carcinoma. The interest in thyroid cancer increased in response to three factors: the introduction of Thyrogen with the associated advertising by Genzyme to promote its use, the increase in the incidence of thyroid cancer (higher than any other cancer, in both sexes, at all age groups, and without any known reason), and the increased interest of researchers in this disease as other areas of grant support dried up and new pharmaceuticals became available with potential application.
Unfortunately, most physicians in practice were trained in the years when there was little interest in thyroid cancer and also little education for physicians in thyroid cancer. Accordingly, physicians in practice of become dependent upon different proclamations from varied "experts" in thyroid cancer (a field with a long tradition of strongly held and diverging opinions). Since the outcomes of different approaches to therapy often do not become apparent for several decades, most physicians treating patients do not see the consequences of their treatment approaches. Thus, most are very dependent upon "Practice Guidelines" and the "publication du jour" in the medical literature (not withstanding the truism that you can find six different and opposing opinions published in the medical literature on almost any topic).
There is an opinion, not shared by me, that radioiodine scans are not needed and can be supplanted by thyroglobulin assessment in many if not most patients. Unfortunately, although it is more common for cancers to lose iodine uptake long before they lose the ability to produce thyroglobulin, the opposite clearly happens in a number of patients. Also, radioiodine scans are the unique diagnostic studies that often clearly point towards a therapeutic approach (radioiodine therapy).
My best suggestion is to obtain the expertise of a physician that is trustworthy to you. The confidence in your medical care is far more important than the inconvenience in traveling longer distances to see your physician. I have many patients who travel across continents to see me. Some patients have resources to fly commercial flights and some use "Angel Air" and other charitable organizations. I would not even think twice about driving 6 to 8 hours to see a specialist that I had confidence in for an important medical condition, if I hadn't the confidence in a nearer physician. Everyone makes their own priority of choice.
—ThyroidCancerHelp, August, 2007
Physician (talk to your)
First, it is an excellent general policy to always talk to your own physician first. All physicians, by the nature of their profession are "approachable". Be brave. If they truly reject your inquiries and do not explain their actions, they are violating sacred rules regarding informed consent. Patient's shyness should never come between them and their physician. If the physician fails in their responsibilities to try to answer your questions, seek a different physician. On the other hand, no physician knows everything (including yours truly) and should not be expected to.
—ThyroidCancerHelp, July, 2007
Pleural metastases
It is very difficult to deal with pleural metastases of thyroid cancer that produce fluid in the pleural space (pleural effusion). Generally, I advise that patients in such circumstances have the pleural effusion drained and then undergo pleurodesis (chemical sclerosis of the pleural lining to prevent further fluid accumulation).
Revlimid (lenalidomide) is currently undergoing phase 2 clinical trial evaluation in my Thyroid Oncology Program. I do not advocate off-label use by other physicians, particularly before our trial results are reported in a proper venue. There are a number of important caveats regarding its use that would not be known by other physicians without our two-year experience in using it for thyroid cancer. It is highly recommended that such physicians contact me directly via 800-888-5533 (PHYSICIAN-ONLY NUMBER) to obtain critical information.
—ThyroidCancerHelp, March, 2008
Poorly differentiated (thyroid cancers)
There are two circumstances in which thyroid cancers are characterized as "dedifferentiated." One is the appearance under the microscope. This often, but not always, when appearing poorly differentiated suggests that the tumor will be behaving in a "poorly differentiated" manner. The most important aspect of being "poorly differentiated" is the behavior of the tumor. Differentiated tumors grow slowly, spread reluctantly, take up iodine very well, make thyroglobulin, are stimulated by TSH when it is elevated, and tend to be suppressed when TSH levels are low. The degree to which these "differentiated" features are lost is the degree to which the tumor is "poorly differentiated."
It's important to remember that even poorly differentiated tumors may be dealt with expeditiously by appropriate therapy. My practice is highly enriched in those patients with poorly differentiated thyroid cancers because this is the object of my research for the past two decades. Many times such people do very well. When they don't they often require creative approaches to their therapy or participate in one of my clinical trials.
—ThyroidCancerHelp, August, 2007
Post therapy scans vs. anatomical imaging studies
Post therapy I-131 whole body scans (performed 2-7 days after a treatment dose of I-131) are the most sensitive tests for detecting iodine-avid metastases. There is no "size limit" to the abilities of these scans that is easily defined, but sometimes MICROmetastastic tumors are not well-visualized, accounting for how radioactive iodine treatments can reduce thyroglobulin levels even when the post-therapy scan is negative.
This FUNCTIONAL property of post-therapy scans is unrelated to the ANATOMICAL imaging properties of CT scans, MRI scans, and ultrasounds. Such studies are complementary, not exclusionary.
—ThyroidCancerHelp, December, 2007
Pregnancy can stimulate persistent thyroid cancers
It is not unexpected for a person with persistent thyroid cancer to have this cancer stimulated by a pregnancy. It is clear that suppression of TSH with sufficient thyroid hormone suppresses the cancer (and the thyroglobulin level) by avoiding stimulation of the TSH receptors on the thyroid cancer cells.
On the other hand, during pregnancy the level of human chorionic gonadotropin (HCG; produced by the placenta) rises to extremely high levels. In the mid 1970's, Dr. Jerry Hershman was the first to demonstrate that high levels of HCG seen in pregnancy will stimulate the TSH receptor on thyroid cells as if it were actually TSH. It would be expected that TSH receptors on thyroid cancer cells would be stimulated in the very same way. The rise in thyroglobulin seen during pregnancy, in a thyroid cancer patient with persistent tumor, is caused by the HCG even though the TSH is still well suppressed.
Hopefully, once the pregnancy has successfully been completed and the HCG levels decline, the thyroglobulin will decline to its typical baseline level. If not, a careful search for the sites of the tumor should be resumed.
—ThyroidCancerHelp, June, 2007
R
Radiation exposure causing thyroid cancer
Not every exposure to radiation, even as a fetus, is sufficient to increase the risk for thyroid cancer. Typical exposures used for diagnostic radiology tests do not add to risk of this disease. Radioactive fallout, such as seen with Chernobyl in 1986, does enhance the risk. External beam radiation therapy that hits the thyroid gland of a fetus or child does enhance the risk.
There is great variability in whether such a cancer will develop, even in people with identical radiation exposures. This is because the radiation enhances the chance of random genetic mutations or, more likely, gene translocations. All of these are still probabilistic events and are not guaranteed to occur.
—ThyroidCancerHelp, July, 2007
Radiation-induced thyroid cancer
It is not clear whether radiation-induced thyroid cancers (usually papillary cancers) are intrinsically different from those that arise because of other causes. Certainly, it was thought that they were not different until the thyroid cancers that were caused by the Chernobyl radiatioactive fallout were analyzed. In those cases, there seemed to be a large number of diffuse-sclerosing variant of papillary carcinoma; a variant that otherwise was quite unusual and not previously common in children. The thyroid cancers seen in the Chernobyl children were also unusual in that the latency period, the time between the radiation exposure and the time that the cancer was discovered, was unusually short, at least a decade shorter than seen previously.
Considering that there appears to be a world-wide increase in new thyroid cancer cases, exceeding the rate of increase of any other cancer type, and most of these are clearly not associated with previous radiation exposure, it would be very difficult to assign a specific causation to any particular case of thyroid cancer.
Generally, if a person has been born and raised in a region of the country (and time period) that has been known to have been exposed to nuclear testing fallout and they were in a high-risk category (for example, drinking fresh milk from a family farm), then there is an assumption that the cancer could have been caused by radiation. Likewise, if a small child has been treated with mantle external beam radiation for Hodgkin's disease and 12 years later develops thyroid cancer, it is a reasonable presumption that the radiation caused the thyroid cancer; however, it remains a presumption that cannot (as of yet) be proven.
Some researchers have identified specific gene translocations that appear to be associated with ionizing radiation exposure, following a pattern suggested by the three-dimensional nuclear chromosome arrangement; however, this is not yet sufficiently verified as specific for radiation-induced cancers and certainly does not include all possible genetic changes.
As far as therapy, there is no difference in the approach to such patients, compared to any other similar type or extent of disease presentation. The appropriate surgery is the same and the need for lymph node resection is the same. Follow-up care with radioactive iodine and scanning is not any different. Like thyroid cancers from any other cause, known or unknown, some tumors are responsive to conventional treatments and some are not.
—ThyroidCancerHelp, September, 2007
Radiation safety: how to properly read the literature
The internet can be a very DANGEROUS place for people without proper literature research habits to draw erroneous conclusions from inappropriate interpretation of published ABSTRACTS. It's a good practice to READ THE ENTIRE PAPER, rather than only the abstract.
In the case of the 1978 Jacobson paper, cited above, the study was performed on patients with Graves' disease (hyperthyroidism) with radioactive iodine doses ranging from 8 to 19.7 mCi. These patients were NOT told to avoid transferring radioactive bodily fluids (wet kissing, sex, etc.) and the investigators feel that this was the cause of exposure to other family members. Remarkably, the only case of thyroid cancer therapy in this study (using 150 mCi I-131) was the only family without any appreciable radiation exposure from the treated family member.
I suggest that members read papers published in THIS century that study the appropriate patient population using modern techniques. Publications (such as: Grigsby PW, Siegel BA, Baker S, et al: Radiation exposure from outpatient radioactive iodine (131I) therapy for thyroid carcinoma. Jama 283:2272, 2000) will demonstrate that appropriate simple precautions avoid any significant radiation exposure to other family members.
—ThyroidCancerHelp, August, 2007
Radioactive iodine administration TSH levels
Studies of TSH levels required for optimal stimulation of thyroid cancer cells and thyroid remnants to take up radioactive iodine show a level of 30 mIU/L to be a reasonable minimal threshold. Higher levels are fine, but lower levels are less than optimal. These numbers are based on hypothyroid (thyroid hormone withdrawal) preparation methods.
When scans are performed using Thyrogen, patients are still taking their levothyroxine therapy. Thyrogen injections are typically administered on Day #1 and Day #2 with the radioactive iodine tracer given on Day #3 and the scans performed (in my patients) on Days #4 and 5. Although the TSH level is presumably sufficient to stimulate the uptake of the tracer dose on Day #3, thyroglobulin levels are obtained on Day #5 (because of the lag time needed for the cells to "rev up" sufficiently to make thyroglobulin). If TSH levels are obtained on Day #5, they are often much lower than 30; however, this is not considered evidence of inadequate TSH stimulation under such circumstances.
—ThyroidCancerHelp, July, 2007
Radioactive iodine (and breast feeding)
It is critically important to totally terminate breast feeding prior to any radioactive iodine scanning or treatment dose. The radiokinetics of radioactive iodine would not permit breast-feeding for AT LEAST 60 days in order to avoid destroying the baby's thyroid gland or causing thyroid cancer in the baby. There is no sense to continue lactation, discarding the milk, and resuming more than 2 months later since the baby would already be weaned from breast feeding. This is not just a recommendation. It is a necessity. I do not believe that any nuclear medicine facility should knowingly administer any radioactive iodine to any woman who is intending to continue breast feeding. This does not apply to later pregnancies, provided that there is no need for further scanning and therapy. As a practical guideline, women thyroid cancer patients should tend to avoid breast-feeding their children if there is any reasonable chance that they would need to receive radiopharmaceuticals at anytime while breast-feeding.
There is an additional theoretical risk that a lactating breast is more prone to concentrate radioactive iodine within it, providing a substantial radiation dose to the woman's breasts. For all of these reasons, it is best to discontinue lactating for at least 2 months prior to radioiodine administration. Please also note that hypothyroidism, besides causing increased TSH levels, will increase prolactin levels and provide an additional stimulus to a primed, recently lactating breast.
—ThyroidCancerHelp, August, 2007
Radioactive iodine (determinants of response to)
Thyroid cancer cells in tumors may be heterogeneous, many of these cells varying in their abilities to take up and retain radioactive iodine. Under those circumstances, these features determine the ability of these cells to respond to radioactive iodine, provided that there is optimal preparation for the treatment and a sufficient radioactive iodine dose is given. When the combination of tumor cell responsiveness, preparation, and radioactive iodine dose is sufficient, there is a successful treatment. When any one of these three categories is sufficiently impaired, the treatment is not successful. Sometimes the treatment is partially successful; however, a minority of tumor cells did not take up the radioiodine sufficiently to have a complete success. In that case, the treatment was useful but insufficient.
On the other hand, when there is macroscopic tumor (bigger than microscopic) that clearly does not take up radioactive iodine as seen on the scan, there is no point to further radioactive iodine therapy.
—ThyroidCancerHelp, September, 2007
Radioactive iodine in persistent lung metastases (use of)
PET scans are two-edged swords. On one hand, a positive PET scan can demonstrate the location of a thyroid cancer metastasis, accounting for elevated thyroglobulin levels. On the other hand, when a thyroid cancer metastasis shows FDG (radioactive sugar) uptake on a PET scan, it often means that the tumor is rapidly growing and has a good chance of being de-differentiated and not able to take up radioactive iodine.
When thyroid cancer is metastatic to distant sites, such as the lung, there are no well-proven effective therapies, aside from radioactive iodine. In such a situation, even if the tumor is suspected of not being able to take up radioactive iodine, we often make a final effort with I-131. This either proves helpful or at least definitively demonstrates the futility of further attempts with I-131. The theoretical risk of leukemia from the radioactive iodine is without practical merit (I do not have such cases despite using the highest doses of I-131 in many such appropriate patients in my practice for over 20 years).
When this radioactive iodine therapy is attempted, it is CRITICAL to make certain that the preparation for the treatment is OPTIMAL. This means the following: 1) using a hypothyroid preparation (with TSH >30; Thyrogen is less effective than hypothyroidism for this purpose), 2) a strict low iodine diet (if iodinated contrast dye has been used within the past 8 months, a 24-hour urine iodine assessment should be done while on a low iodine diet, verifying less than 100 mcg iodide in the total urine collection). 3) the highest "safe" dose of I-131 able to be used, provided that there has not yet been any compromise of the bone marrow (normal blood counts). The only established method is to do I-131 dosimetry; however, since this is not widely available, the dose should generally be at least 200 mCi.
If the known sites of tumor do not show any uptake of the radioactive iodine therapy dose, when assessed on a post-therapy whole body scan (performed at 48 hours after the treatment in our hands), then this clearly defines the end of any further use of radioactive iodine for this patient. Under such circumstances, the next appropriate step is consideration of participating in a clinical research trial (for example, my phase 2 trial of lenalidomide, if the entry criteria are met).
—ThyroidCancerHelp, July, 2007
Radioactive iodine scans (difficulties in interpreting)
There are many areas that normally will take up radioactive iodine that have nothing to do with thyroid cancer. Their are areas of normal "physiological" uptake of radioactive iodine on a whole body scan (WBS) and there are sometimes perfectly clean WBSs are misinterpreted. Some common errors include: 1) mistaking salivary gland uptake for tumor sites; 2) mistaking radioactive saliva coating the esophagus for tumor sites; 3) mistaking gastric uptake for tumor; 4) mistaking hepatic "blush" for liver metastases (organified radioiodine from tumors other sites of the body is taken up by the liver without tumor being present in the liver); 5) kidney/ ureter/ bladder uptake sites mistaken for tumor sites; 6) radioactive stool scattered in the small and large intestine being mistaken for tumor sites; 7) stool in the appendix or colonic diverticula mistaken for tumor sites; 8) radioactive perspiration or saliva on the skin mistaken for tumor sites; 9) physiological breast uptake or fibrocystic breast uptake mistaken for tumor metastases; 10) benign cysts in the neck/ kidneys/lungs/ liver/ etc. mistaken for tumor metastases; 11) sucking on a pigtail with radioactive saliva that lays across the neck mistaken for tumor metastases, 12) pulmonary bronchiectasis mistaken for tumor metastases to the lungs, 13 etc. and etc. and etc.
—ThyroidCancerHelp, August, 2007
Radioactive iodine therapy and need for focality
Focality refers to the number of thyroid cancer nodules (tumors) within the thyroid gland. Unifocal means that there is only one thyroid cancer tumor within the thyroid gland. Multifocal means there are two or more such tumors within the thyroid gland.
For papillary thyroid cancers, (including: typical papillary, follicular variant of papillary, and occult sclerosing papillary tumors) tumor nodules that are 1.0 centimeters, or less, in diameter are called microcarcinomas. Unifocal papillary microcarcinomas that are completely contained within the thyroid gland and are not associated with any local or distant sites of cancer (metastases) are considered to be very low risk and are not usually treated with radioactive iodine after the thyroid surgery.
There has previously been a controversy about multifocal papillary microcarcinomas, whether they warrant completion of partial thyroidectomies and radioactive iodine therapy. In my experience, and supported by recent studies, multifocal tumors, even multifocal microcarcinomas, are sufficiently aggressive and have sufficient metastatic potential to warrant radioactive iodine therapy.
All other types of thyroid cancer, including follicular, insular, Hurthle cell variants, tall cell variants, and columnar cell variants are considered sufficiently significant to warrant total thyroidectomy and radioactive iodine therapy no matter how small and both unifocal and multifocal.
—ThyroidCancerHelp, October, 2007
Radioactive iodine therapy and teeth cleaning
Since routine teeth cleaning is not typically considered urgent or emergency care, it would be most appropriate to wait for this service until after 2 weeks from a radioactive iodine therapy dose. If the dose was a very large one (>200 mCi), then it's best to wait for 2 months because tooth cleaning forces some bacteria to enter the blood and the blood count fully recovers by that time.
If someone has had teeth cleaning during this time, there shouldn't be any concern because the "Universal Precautions" that the dentist should be using (intended to deal with germs and viruses) will be sufficient to avoid significant radioactivity contamination.
—ThyroidCancerHelp, October, 2007
Radioactive iodine therapy and vaccinations
The effects of radioactive iodine therapy upon the immune system vary, depending on the dosage administered and the particular way that each person handles it. Doses of I-131 exceeding 200 mCi in most patients (lower in some older patients and those with poor kidney function) can be shown to cause the white blood cell counts to decrease, reaching their lowest point 4 weeks after the treatment and recovering by 8 weeks.
How this may effect response to a vaccination has not been studied. Additionally, the effects of smaller doses of I-131 on immune responses to vaccinations has not been studied. For that reason, if there is any concern, common sense would suggest to either obtain a vaccination several weeks before an I-131 treatment or to wait at least 2 months after such a treatment.
—ThyroidCancerHelp, October, 2007
Radioactive iodine therapy (clearing up myths regarding)
The following addresses common myths and fears about RAI:
1) I do not consider it controversial to treat thyroid cancer patients with radioactive iodine. Considering the complete absence of any alternative treatment to deal with systemic disease, the clearly demonstrated ability of radioactive iodine to eliminate metastatic tumor deposits, and the mortal and morbid consequences of unchecked tumor spread and progression, the choice to avoid radioactive iodine therapy for clinically significant thyroid cancer is definitely not advised. It is not usually necessary to treat a typical papillary thyroid microcarcinoma that is unifocal, because such tumors have a low risk of spread and recurrence. On the other hand, there is NO controversy about treating 2.5 cm tumors among any physicians with training and experience in thyroid cancer. The deficit in population studies regarding this treatment is unrelated to individual patient care and mostly related to the lack of funding, interest, and attention to this issue in the past. Prospective studies take decades before they yield interpretable results.
2) Woman who have received radioactive iodine therapy for thyroid cancer do not suffer infertility or problems with subsequent birth defects in any way greater than if they had not received radioactive iodine.
3) The issue of "secondary cancers" from radioactive iodine is not of importance. Such issues are useful to consider in regards to treatment of benign disease, such as for Graves' disease, but even in these situations the data shows no significant definable risk for individual patients (one additional case out of 10,000 is of lesser consequence than the risk of fatality from driving your car home from the doctor). In regards to thyroid cancer, anyone who desires to NOT treat an existing cancer because of a theoretical, unlikely, and unsubstantiated possibility of some other cancer is lacking common sense.
4) Thyroid cancers do not "improve" with time; they tend to de-differentiate and become less responsive to treatment. Waiting and permitting tumor cells with more aggressive genotypes to grow and replace the population of tumor cells is very unwise. I cannot perceive of any advantage to delaying treatment for an uncertain future without valid reason.
5) If patients choose to follow courses of treatment that are poorly thought out, I try to educate them. I find it ethically challenging to be responsible, as their physician, for managing poor treatment choices. Anyone can vote with their feet and find a physician to do anything that is desired; but competent physicians cannot be compelled to administer incompetent care. For that reason, I do not have "alternative follow-up plans" for patients who make such unwise choices.
—ThyroidCancerHelp, October, 2007
Radioactive iodine therapy (recovery from hypothyroidism and)
When I restart levothyroxine therapy (using the full suppression dose), after hypothyroid preparation for radioiodine scans or therapy, I usually simultaneously start Cytomel in a tapering schedule. For the first 6 days Cytomel is taken as 25 micrograms twice daily, the next 7 days the dose is 12.5 micrograms twice daily, and the final 6 days the dose is 12.5 micrograms each morning only and thereafter stopped. The Cytomel dose is tapered sooner or stopped sooner if there are any thyrotoxic symptoms. Despite this combined treatment approach, I advise patients to avoid driving or performing brain surgery for 10 days.
—ThyroidCancerHelp, October, 2007
Radioactivity conversion: curies to becquerels
Just as most of the world uses meters and centimeters rather than yards and inches, much of the world is using Becquerels rather than Curies. Personally, I much prefer Marie Curie to Henri Becquerel; however, nobody asked for my input regarding the nomenclature. These terms are used as a measure of radiation activity (radioactivity). A Curie (Ci) is equal to the radioactivity of one gram of Radium
= 37 billion atomic disintegrations per second
= 37 billion Becquerels (Bq) [new term] = 37 GBq
Using the conversion: 1 mCi (milliCuries) = 37 MBq
(million Becquerels) = 0.037 GBq (billion Becquerels).
100 mCi = 3.7 GBq = 3,700 MBq
200 mCi = 7.4 GBq = 7,400 MBq
It's very important to know the exact type of units used before the numbers are interpreted.
—ThyroidCancerHelp, September, 2007
Radioiodine scans (pregnancy after)
The reason to wait two months [before conceiving] after completing a HYPOTHYROID scan is that you do not want to conceive a baby while still hypothyroid, not because of any radiation risk (there isn't any). If a person has been scanned while still on thyroid hormone (using Thyrogen), then there is no reason for any delay at all. Please make certain to have as much fun as you can while trying to get pregnant.
[As for the common misperception about conception after radioactive iodine], the human body is not a sealed bottle. The half-life of I-131 vs. I-123 is much less important than the very brief biological half life of these isotopes in a person who has no thyroid gland. The combined effects of the physical half-life and the biological half-life is called the "effective" half-life. The effective half-life of an I-131 scan dose is so brief that there would not be any biological effect upon a fetus conceived within 3 days of a 5 mCi or less tracer dose.
The reason why I advise a delay in conception until 2 months after a hypothyroid I-131 scan is SOLELY due to the well-known effects of hypothyroidism upon the first 8 weeks of an embryo's existence.
—ThyroidCancerHelp, September, 2007
Radioactive iodine therapy and fertility
Appropriately administered radioactive iodine therapy should not have any significant effect on fertility nor cause any birth defects as given in the majority of patients. The only exception MAY be in patients given VERY high radioactive iodine doses (multiple dosimetry-limited doses, usually at more than 2000 mCi cumulative exposure) and even in many such patients (as I have personally cared for) I cannot recall more than a single case of infertility (in a male) and no cases of birth defects in subsequent offspring. When thyroid cancer is sufficiently aggressive and spread throughout the lungs, issues of fertility should be much less a consideration than issues of survival and long life.
—ThyroidCancerHelp, July, 2007
Radioactive iodine therapy (follow-up evaluation after initial)
Follow-up of differentiated thyroid cancer after surgery and radioactive iodine treatment is very important. It is necessary to be aware of treatment related effects (such as swelling of salivary glands from thickened saliva due to damage by radioactive iodine) so that these can be distinguished from enlarged lymph nodes. Not all "lumps" seen on ultrasounds are related to thyroid cancer; however, any that are suspicious should be evaluated with a fine needle aspiration biopsy.
Likewise, assessment for residual tumor after initial radioactive iodine therapy entails combined use of functional studies (follow-up radioactive iodine scans, stimulated thyroglobulin levels), physical examination, and anatomical studies (ultrasound, bone xrays, CT of chest without contrast, MRI scans of abdomen and pelvis if appropriate). The best choice of which test to perform and at which time is made with consideration of any symptoms or complaints from the patient. It cannot be done as from a "cookbook", but requires a skilled physician to determine the follow-up plan for that particular patient.
—ThyroidCancerHelp, July, 2007
Radioactive iodine therapy (low vs. high-dose)
When you have a streptococcal throat infection and take the full course of penicillin, there is a very good chance that you will obliterate it. This is despite the fact that the population of strept germs have varying amounts of resistance to the penicillin. It's just that the penicillin dose is usually high enough to overpower the resistant germs. However, if you take only part of the penicillin prescribed, there is a very reasonable chance that most of the germs have been killed (and you feel much improved) but there are still a few germs that were inherently a bit more resistant to the penicillin and they will survive. These resistant germs gradually increase in number and cause another throat infection; however, now they are super-enriched in penicillin-resistant germs and will not be cured with even the full course of penicillin.
When thyroid cancer patients were treated with radioactive iodine, the many millions of thyroid cancer cells inside such a person have varying sensitivities to radioactive iodine (differing abilities to take it up, hold on to it, repair DNA damage from the radiation, etc.). If a "low dose" of radioactive iodine is used, particularly for several treatments, the population of surviving cancer cells become highly enriched in radioiodine resistant cells and will no longer respond to such treatments, even when high doses are given. On the other hand, if high radioactive iodine doses are used (much like a "full course of penicillin") the chance that the initial population of slightly-resistant cells will survive and proliferate becomes much less. The success of the treatment becomes much more likely.
Unless you have a more-effective systemic (affecting tumor cells in the entire body) therapy for thyroid cancer, there is no reason to avoid radioactive iodine therapy. You should only beware of treatments that are low-dose, or given with such poor preparation (no low iodine diet) that they are no better than low dose treatments.
—ThyroidCancerHelp, September, 2007
Radioactive iodine treatment (traveling after)
It is a good idea to obtain a letter from your nuclear medicine physician that documents the date and dose of radioiodine therapy. This is necessary so if a radiation monitor is set off at the airport, you are not improperly accused of smuggling components for a nuclear bomb.
—ThyroidCancerHelp, August, 2007
Radioactive iodine uptake
The presence of measurable thyroglobulin levels, even as low as 2, indicates the presence of persistent thyroid cancer. The presence of thyroglobulin at higher levels indicates the presence of larger amounts of tumor. There are three common errors made in the followup of thyroid cancer: 1) permitting measurable thyroglobulin to be present without fully searching for the tumor source, 2) presuming that any persistent thyroid cancer MUST be in the neck despite the fact that it can spread to anywhere in the body, and 3) presuming that thyroid cancer ALWAYS takes up radioactive iodine. Sometimes, unfortunately, it loses this ability and will not respond to radioactive iodine for either therapy or scans. As long as interference from non-radioactive iodine is ruled out, the presence of thyroglobulin in the blood should instigate a full assessment of the entire body using a variety of radiological techniques and sometimes using PET scans.
—ThyroidCancerHelp, June, 2007
Radioactive iodine uptake: proper preparation is necessary to assess
Stable (non-radioactive) iodine from dietary sources or from CT scan contrast dye (or similar dye used for angiograms and other radiology tests) can certainly make a thyroid cancer appear to fail to take up radioactive iodine, even when it is clearly able to do so. It is unfortunate that so many physicians do not understand this at all.
Clearly, if the assessment of radioactive iodine uptake, using a scan with proper elevation of the TSH, is compromised by the presence of stable iodine, it will make the scan FALSELY negative. The assessment of the iodine uptake capabilities of thyroid cancer deposits in the body necessitates appropriate preparation. If it's not done properly then all bets are off.
—ThyroidCancerHelp, June, 2007
Radioiodine dosimetry (very few medical centers are known to do)
Unfortunately, the list is very small. The sites that are known to me include:
1. University of Kentucky Medical Center
2. Memorial Sloan-Kettering Cancer Center
3. National Institutes of Health
4. Washington Medical Center, Washington, D.C.
5. University of Washington, Seattle, WA
6. Queen's Medical Center, Honolulu, Hawaii
7. University of Cincinnati used to do it before Dr. Maxon retired, but now ?
There is a site in Boston that claims to do dosimetry but the few patients known to me that received it there were not managed properly.
—ThyroidCancerHelp, September, 2007
Radioiodine therapy doses (intervals between)
In regards to the intervals between radioactive iodine therapy doses:
1). Radioiodine effects on killing thyroid cancer cells may take a few months to fully manifest. Although the I-131 is effectively gone in a few days, some of the tumor DNA damage caused by the ionizing radiation does not result in the death of the cancer cell until some time later when it tries to divide and replicate.
2). For those tumor cells not killed by the radioiodine dose, there is likely to be some residual "stunning" by their exposure to sublethal radiation, causing inability to take up the next I-131 dose and resulting in subsequent radioiodine treatment failure, if attempted too soon after the first treatment. Recovery from this effect can take a few months.
3). Every I-131 treatment dose has some temporary adverse effect upon the bone marrow cells. It takes several months for this to be minimized so that adverse effects do not accumulate and result in otherwise avoidable toxicity.
For these reasons, and others, it is inadvisable to attempt I-131 therapies closer together than 5-6 months. For some patients, in whom I have administered dosimetry-limited (maximal marrow toleration) I-131 doses (300-950 mCi per dose) for severely aggressive disease, the interval between doses may be even greater. Since I consider it ill-advised to prepare a patient for I-131 whole body scanning if the physician does not intend to treat any detected disease, I do not do I-131 scanning at intervals closer together than those defined for therapy (as above). This approach is based on the methodology utilized at the University of Kentucky Thyroid Oncology Program and may be different than approaches of some other clinicians.
—ThyroidCancerHelp, July, 2007
Radioiodine therapy (radiation safety after): A primer
In reviewing many emails on the ThyCa list-serve for a dozen years, I've been amazed by the absurd extremes and unwarranted fears generated by radiation safety concerns. Noting that there are administrative radiation safety precautions" usually printed on colored paper and dispersed by nuclear medicine departments as if they were holy scripture; at the risk of being sacrilegious, I prefer to provide my patients with information based upon actual radiobiological common sense. My own recommendations follow:
COMMON SENSE REGARDING RADIATION SAFETY AFTER RADIOACTIVE IODINE TREATMENTS
Radiation safety precautions are based upon a very reasonable consensus public policy that individuals, who do not require exposure to radiation for their own health, should have the least exposure to radiation as is reasonably achievable. The acronym that is commonly applied is "ALARA" (As Low As Reasonably Achievable).
Such precautions have been designed because of this PUBLIC POLICY and NOT because health professionals expect radioactive iodine patients to be dangerous or harmful to anyone else. In fact, I can conceive of only three examples of situations in which a radioactive iodine therapy patient could "endanger" or cause "harm" to someone else: 1) If a cannibal should chance to devour the patient immediately upon discharge, this cannibal might experience dysfunction of their thyroid gland; 2) If someone would try to drink all of the urine produced by a patient for the two days following discharge, they might also expect dysfunction of their thyroid gland; and 3) If a patient would breast-feed a child within two weeks of such a therapy the radioactive iodine might be likely to damage the infant's thyroid gland. Lactation during therapy would also provide excessive radiation to the patient's breasts and is an additional reason why lactation must be discontinued for a couple of months prior to receiving radioactive iodine treatment.
Besides the three situations listed above, it is NOT CONCEIVABLE that any MEASURABLE HARM could result from a radioiodine therapy patient. The general precautions given to every patient after such therapy, below, are provided solely to support the reasonable ALARA public policy.
Please maintain simple radiation safety precautions for the next 14 days. Do not exchange bodily fluids with anyone (no sex, wet kissing, sharing utensils, etc.). Please urinate while sitting (instead of standing). You may use normal non-porous eating utensils and dishes/cups, but wash them before anyone else handles them. Dispose of your toothbrush after 14 days. Try to place a reasonable bit of distance between yourself and others. One useful technique is to imagine that you have a "streptococcal throat infection"; the distance that others should keep from you would be similar, as would the bodily fluid precautions. Do not sleep in the same bed as others for this time. There is no need for these precautions after 14 days.
Although these precautions, listed above, may differ from the specific instructions provided by different radiation
safety agencies, they embody the same principles and same respect for the ALARA policy.
No one should go to absurd measures of isolating themselves from everyone else for days on end. Patients need not place their children in foster care. It is supremely foolish to try to "disinfect" things (radioactive iodine is not alive and is not a germ nor virus); a little soap and water suffice for items that have been dampened by radioactive bodily fluids. Do not fear eating in restaurants. If restaurant employees follow the required public health policies for washing utensils, dishes and cups, they will not be exposed to radiation. If they fail to follow these policies, they're at far greater risk from gonorrhea, syphilis, herpes and other contaminants of customers' saliva than they are from a trace amount of radioactive iodine. Likewise, the employees of hotels in their handling of towels and linens are far more at risk from their guests' influenza viruses and sexually transmitted diseases on bed-sheets if they mishandle them, than they ever could be from trace radioactivity.
As in most things regarding health and safety, common sense and intelligent behavior trumps fear and neurotic excesses every time.
—ThyroidCancerHelp, July, 2007
Radioiodine therapy: my recommendations
I cannot account for the extremely diverse instructions that different physicians and institutions give to their patients after radioactive iodine. Sometimes the advice makes sense, but often it seems non-sensical and comes from baseless custom, suppositions and groundless fears. All that I can do is to provide you the recommendations that I provide my own patients for after their radioactive iodine therapy:
1) Thyroid hormone: I resume full doses of levothyroxine at 24 hours after the radioactive iodine dose is swallowed. All of the useful uptake of radioactive iodine into the thyroid cancer cells takes place within the first 24 hours. Despite starting the full dose of levothyroxine, the TSH will remain very high (in patients prepared by hypothyroid withdrawal) for at least 1 to 2 more weeks. In addition, I provide a tapering off supplementation with Cytomel (liothyronine) over the first 3 weeks to enhance my patients' return to normalcy.
2) Low Iodine Diet: Considering that I was the physician who first popularized this diet and provided this diet to ThyCa more than a decade ago and am considered to be very strict about the low iodine diet, I find it ludicrous that some physicians keep patients on the diet for considerable lengths of time after the radioactive iodine therapy. For the same reason cited above (the completion of radioactive iodine uptake within 24 hours), I have patients resume a normal diet at 24 hours after taking the radioactive iodine. There is no reason to maintain the LID for the performance of the post-therapy whole body scan because this scan only reveals the radioactive iodine ALREADY taken up by thyroid cancer cells.
3) Radiation Safety Precautions: (Here I'll include a very long email that I've posted in earlier years on the ThyCa listserve):
COMMON SENSE REGARDING RADIATION SAFETY AFTER RADIOACTIVE IODINE TREATMENTS
Radiation safety precautions are based upon a very reasonable consensus public policy that individuals, who do not require exposure to radiation for their own health, should have the least exposure to radiation as is reasonably achievable. The acronym that is commonly applied is "ALARA" (As Low As Reasonably Achievable).
Such precautions have been designed because of this PUBLIC POLICY and NOT because health professionals expect radioactive iodine patients to be dangerous or harmful to anyone else. In fact, I can conceive of only three examples of situations in which a radioactive iodine therapy patient could "endanger" or cause "harm" to someone else: 1) If a cannibal should chance to devour the patient immediately upon discharge, this cannibal might experience dysfunction of their thyroid gland; 2) If someone would try to drink all of the urine produced by a patient for the two days following discharge, they might also expect dysfunction of their thyroid gland; and 3) If a patient would breast-feed a child within two weeks of such a therapy the radioactive iodine might be likely to damage the infant's thyroid gland. Lactation during therapy would also provide excessive radiation to the patient's breasts and is an additional reason why lactation must be discontinued for a couple of months prior to receiving radioactive iodine treatment.
Besides the three situations listed above, it is NOT CONCEIVABLE that any MEASURABLE HARM could result from a radioiodine therapy patient. The general precautions given to every patient after such therapy, below, are provided solely to support the reasonable ALARA public policy.
Please maintain simple radiation safety precautions for the next 14 days. Do not exchange bodily fluids with anyone (no sex, wet kissing, sharing utensils, etc.). Please urinate while sitting (instead of standing). You may use normal non-porous eating utensils and dishes/cups, but wash them before anyone else handles them. Dispose of your toothbrush after 14 days. Try to place a reasonable bit of distance between yourself and others. One useful technique is to imagine that you have a "streptococcal throat infection"; the distance that others should keep from you would be similar, as would the bodily fluid precautions. Do not sleep in the same bed as others for this time. There is no need for these precautions after 14 days.
Although these precautions, listed above, may differ from the specific instructions provided by different radiation safety agencies, they embody the same principles and same respect for the ALARA policy.
No one should go to absurd measures of isolating themselves from everyone else for days on end. Patients need not place their children in foster care. It is supremely foolish to try to "disinfect" things (radioactive iodine is not alive and is not a germ nor virus); a little soap and water suffice for items that have been dampened by radioactive bodily fluids. Do not fear eating in restaurants. If restaurant employees follow the required public health policies for washing utensils, dishes and cups, they will not be exposed to radiation. If they fail to follow these policies, they're at far greater risk from gonorrhea, syphilis, herpes and other contaminants of customers' saliva than they are from a trace amount of radioactive iodine. Likewise, the employees of hotels in their handling of towels and linens are far more at risk from their guests' influenza viruses and sexually transmitted diseases on bed-sheets if they mishandle them, than they ever could be from trace radioactivity.
As in most things regarding health and safety, common sense and intelligent behavior trumps fear and neurotic excesses every time.
—ThyroidCancerHelp, June, 2007
Radioiodine therapy (temporary taste changes after)
It is VERY common for people to have temporary changes in their perceptions of taste after radioactive iodine therapy. This can last from a few days to several weeks at the most. Fortunately, I have never yet come across anyone who has not had a full return of their taste sensations after a little patience.
—ThyroidCancerHelp, August, 2007
Radioiodine uptake in metastatic tumors (loss of)
The decision to attempt high dose radioactive iodine therapy of recalcitrant metastatic thyroid cancer, previously though to be unresponsive to radioactive iodine, hinges upon several important variables.
First, if there is grossly macroscopic tumor (exceeding 1 cm in diameter), particularly in bone, radioactive iodine will not usually provide much therapeutic benefit, even if there is significant uptake.
Second, it's important to try to find the "smoking gun" (i.e. the unwitting iodinated contrast CT scan just before the previous radioiodine therapy) that provides a reasonable explanation for the previous treatment failure and suggests continued potential of I-131 if done properly.
Third, when tumors are seen to suck up radioactive sugar (FDG) on a PET scan, these tumors are usually very metabolically active, more rapidly growing, and less likely to have sufficient differentiated function (i.e. ability to suck up radioactive iodine). In that way, seeing FDG uptake on a PET scan suggests that radioactive iodine treatment is more likely futile.
Lastly, if there is no clearly useful way to eliminate distant tumor metastases, it's often best to maintain good suppression of TSH and monitor for tumor growth and progression. In the absence of growth, it is often best to wait and relax. In the presence of significant growth, it's a good time to look to participate in a clinical trial.
—ThyroidCancerHelp, September, 2007
RAI and breast feeding: A primer
It is important to NOT GET ANY RADIOACTIVE IODINE SCANS or TREATMENTS WHILE BREAST-FEEDING: There is NO WAY to safely breast-feed when given radioactive iodine since the breast actively accumulates iodine from the blood and secretes it into its milk. For the following reasons, It is critically important to totally terminate breast feeding for at least 2 months prior to any radioactive iodine scanning or treatment dose.
The radiokinetics of radioactive iodine would not permit breast-feeding for at least 60 days after receiving a radioactive iodine treatment in order to avoid destroying the baby's thyroid gland or causing thyroid cancer in the baby. There is no sense to continue lactation, discarding the milk, and resuming more than 2 months later since the baby would already be weaned from breast feeding. This is not just a recommendation. It is a necessity.
I do not believe that any nuclear medicine facility would knowingly administer any radioactive iodine to any woman who is intending to continue breast feeding. As a practical guideline, female thyroid cancer patients should tend to avoid breast-feeding their children if there is any reasonable chance that they would need to receive radiopharmaceuticals at anytime while breast-feeding.
In addition, the radiation exposure to the woman's breasts is far higher if she is given radioiodine when recently lactating than in the non-lactating state. Lactation should be terminated for at least 2 months BEFORE administration of more than tracer amounts of radioactive iodine. This may have consequences for future risk of radiation-induced effects on the breasts.
If a patient has been breast-feeding when the thyroid cancer surgery is performed, she should be placed on LEVOTHYROXINE RIGHT AWAY to avoid hypothyroidism until lactation has stopped and the breasts are no longer engorged with milk. Hypothyroidism will increase prolactin levels and prolong the time needed for the breasts to resume their non-lactating state. After the breasts are back to their normal non-lactating state (usually several weeks after weaning) the patient may be placed on Cytomel (liothyronine) twice daily for 4 weeks, then taken off of this (while on a good Low Iodine Diet, www.lidcookbook.com) for 2 weeks as their preparation for I-131 scanning and ablation therapy.
Radiation safety precautions after radioactive iodine should NOT be too terrible if dealt with in an appropriate and rational manner. This should not be a great hardship, even with small children; though an infant's care will need assistance from other family members for only the first two weeks. Please go to the Home Page for this Group on Yahoo and read the following messages: #113, #376, and #749. There should not be any irrational fears generated while undergoing appropriate radioactive iodine therapy.
—ThyroidCancerHelp, January, 2008
RAI and cold sores
Occasionally, the stress of hypothyroidism and radioactive iodine therapy re-activates cold sores (due to latent Herpes simplex type 1 that stay in nerves). Unfortunately, the efforts with "magic mouthwash" are usually the best that can be done, soothing the discomfort until the short-lived problem spontaneously resolves. Although physicians try to alleviate such discomfort, we haven't more effective tools. Fortunately, this should improve quite rapidly.
—ThyroidCancerHelp, February, 2008
RAI and de-differentiation
Unless there are MACROscopic tumors, evident on CT scans or MRI studies, the presence of iodine-avid distant metastases would not be known until AFTER the administration of diagnostic or therapeutic doses of radioactive iodine followed by a whole body scan.
Radioactive iodine does NOT "de-differentiate" thyroid cancers. Rather, it selectively kills those cancer cells that have better uptake of the radioactive iodine. If there are sufficient remaining cells, still viable due to their inability to take up radioactive iodine, then their progeny (after sufficient time for multiple generations of cell procreation) will also fail to take up radioactive iodine. The key is to make as certain as possible that the radioactive iodine treatments are given with optimal preparation and dose so as to avoid leaving cells with "marginal" uptake behind.
—ThyroidCancerHelp, January, 2008
RAI and macroscopic tumors
The situation, of having a hypothyroid preparation for radioiodine administration aggravate gross tumor compressing the spinal cord, would not happen in my patients. That is because, I try to avoid violating a cardinal rule of treatment. That rule says: Never try to use radioactive iodine to treat MACROscopic tumor (particularly in critical sites, such as the spinal cord or brain) without first surgically removing the tumor and then treating the microscopic residual disease with I-131. There is no risk of hypothyroidism causing dangerous growth of tumor, if there is a purposeful effort to surgically resect such gross tumors.
Thyrogen would not be an appropriate agent, hoping to avoid stimulating tumor growth, because the I-131 therapy is not very effective against MACROscopic tumor and even less effective with a Thyrogen preparation (compared to hypothyroid withdrawal).
—ThyroidCancerHelp, January, 2008
RAI and metastatic lymph nodes in the neck
Properly prepared, dosed, and administered radioactive iodine therapy is often effective to destroy papillary or follicular thyroid cancers that have spread to lymph nodes in the neck, provided that these tumor deposits are not too large. If they are sufficiently large, treatment response is best by having these nodes surgically removed and then following this with radioactive iodine therapy.
—ThyroidCancerHelp, January, 2008
RAI and salivary stimulants (after)
The ONLY reasonably-performed study documented the worsening of salivary dysfunction consequent to using lemon candies to stimulate salivary flow during the first 24 hours of radioactive iodine therapy. On the other hand, AFTER 24 hours there is such a severe decrease of the level of radioactive iodine in the circulating blood, that the need for further treatments (of any sort) for the salivary glands is essentially moot. For that reason, I do not advocate ANY use of salivary stimulants at ANY time during or after radioactive iodine therapy. This differs from the recommendations of the study's authors who state that they might suggest use of lemon candy after 24 hours from the I-131 treatment.
The abstract for the study is: Nakada, K., T. Ishibashi, et al. (2005). "Does lemon candy decrease salivary gland damage after radioiodine therapy for thyroid cancer?" J Nucl Med 46(2): 261-6. Salivary gland dysfunction is one of the common side effects of high-dose radioiodine therapy for thyroid cancer. The purpose of this study was to determine whether an early start of sucking lemon candy decreases salivary gland injury after radioiodine therapy. METHODS: The incidence of the side effects of radioiodine therapy on the salivary glands was prospectively and longitudinally investigated in 2 groups of patients with postsurgical differentiated thyroid cancer with varying regimens for sucking lemon candy. From August 1999 to October 2000, 116 consecutive patients were asked to suck 1 or 2 lemon candies every 2-3 h in the daytime of the first 5 d after radioiodine therapy (group A). Lemon candy sucking was started within 1 h after radioiodine ingestion. From November 2000 to June 2002, 139 consecutive patients (group B) were asked to suck lemon candies in a manner similar to that of group A. In the group B, lemon candies were withheld until 24 h after the ingestion of radioiodine. Patients with salivary gland disorders, diabetes, collagen tissue diseases, or a previous history of radioiodine therapy or external irradiation to the neck were excluded.
Thus, 105 patients in group A and 125 patients in group B were available for analysis. There were no statistical differences in the mean age (55.2 y vs. 58.5 y), average levels of serum free thyroxine (l-3,5,3',5'-tetraiodothyronine) (0.40 ng/dL vs. 0.47 ng/dL), and the mean dose of (131) I administered (3.96 GBq vs. 3.87 GBq) between the 2 groups. The onset of salivary side effects was monitored during hospital admission and regular follow-up on the basis of interviews with patients, a visual analog scale, and salivary gland scintigraphy using (99m)Tc-pertechnetate. When a patient showed a persistent (>4 mo) dry mouth associated with a nonfunctioning pattern on salivary gland scintigraphy, a diagnosis of xerostomia was established. RESULTS: The incidences of sialoadenitis, hypogeusia or taste loss, and dry mouth with or without repeated sialadenitis in group A versus group B were 63.8% versus 36.8% (P < 0.001), 39.0% versus 25.6% (P < 0.01), and 23.8% versus 11.2% (P < 0.005), respectively. Permanent xerostomia occurred in 15 patients in group A (14.3%) and 7 patients in group B (5.6%) (P < 0.05). In both groups, bilateral involvement of the parotid gland was the most frequently seen and was followed by bilateral involvement of the submandibular gland. CONCLUSION: An early start of sucking lemon candy may induce a significant increase in salivary gland damage. Lemon candy should not be given until 24 h after radioiodine therapy.
—ThyroidCancerHelp, November, 2007
RAI and sour candy (don’t use)
The facts are this: the only reasonably-performed clinical trial of salivary stimulants demonstrated that sour candies severely worsen salivary damage from radioactive iodine. Additionally, enhanced liquid consumption during radioactive iodine therapy will demonstrably diminish the benefits of radioactive iodine and put one at risk for dilutional hyponatremia, based on classic radiobiology and physiology. There is no doubt that these concepts are not understood or affirmed by some physicians; however, they're just mostly wrong or ignorant. Medical/biological reality is not subject to alteration by polling or voting. Much of the information on the ThyCa website was originally provided by me, but much has been altered and that of some other contributors is not correct.
—ThyroidCancerHelp, November, 2007
RAI dosimetry: A primer
Radioiodine Dosimetry is a long-established technique (first performed in the late 1950's) that permits the physician to accurately ascertain what particular dosage of radioiodine would be the maximal safe dosage for a particular patient at a particular time, in treating their thyroid cancer. It is based on the premise that aggressive disease is best treated with the most aggressive radioactive iodine treatment and provides the information needed to define the safety limits of that treatment.
Although there is a half century experience with this technique, there are very few institutions that have any knowledge or experience in its use. This is because it requires extensive careful measurements, computerized computation, and is not typically reimbursable by insurance (physicians don't get paid). It also requires a desire, on the part of physicians, to use I-131 dosages higher than 200 mCi for appropriate situations; many physicians are clearly unwilling or unschooled in the treatment of aggressive thyroid cancers. For that reason, it is difficult for most patients to get treated using this approach and some patients are treated with dosages over 250 mCi without dosimetry, a process akin to Russian roulette. For example, in the Baltimore/Washington DC area, the only institutions that I know that have successfully performed dosimetry are the Washington Medical Center, the NIH, and Walter Reed Army Hospital. I have been performing many dosimetry studies for more than two decades, but most nuclear medicine facilities do not have sufficient expertise.
During a typical I-131 dosimetry study, after an appropriate hypothyroid preparation and low iodine diet, the patient is given a small tracer dose of I-131 (1—5 mCi) to swallow. Whole body counts of radioactivity (either using a scanner or a counting probe) and blood samples are obtained at 2, 4, 6, 24, 48, 72, and 96 hours after the tracer has been administered. I have my patients take a dose of magnesium citrate on the first evening after the tracer administration, to reduce the radioiodine activity in the gut. On the fifth day, after all of the samples have been collected, we measure the amount of I-131 in each blood sample and use it to compute the amount of I-131 in the blood at each time point. This is plotted against time and the area under the curve integrated. Likewise the whole body counts are similarly plotted and integrated. These values are placed into formulas and used to calculate the beta dose and the gamma dose of radiation to the red marrow. The amount of I-131 that would correspond to a 200 RAD red marrow dose becomes the upper limit for the therapy dose. There are additional restrictions based upon whole body retention and lung retention for patients with massive amounts of tumor in the lung or elsewhere. Typically the red marrow limit is the therapy limit.
Using this approach I have safely and successfully administered single doses of I-131 up to 900 mCi. On the other hand, sometimes the dosimetry reveals an unusual clearance pattern of I-131 so that doses as low as 150 mCi would be unacceptably above the 200 RAD limit. In this way, some patients (particularly elderly patients or those with bad kidneys) are spared getting a therapy dose that might be too dangerous for them. Thus dosimetry enhances safety while also permitting more aggressive treatment.
Since so few institutions have experience with I-131 dosimetry, I would not want to be their first patient experience, particularly since there are many, many opportunities for errors and there are no "off the shelf" computational packages.
—ThyroidCancerHelp, January, 2008
RAI excretion with Thyrogen scans
The rapid excretion of radioiodine when Thyrogen is used (as compared to hypothyroidism) stems from the fact that a hypothyroid kidney works only one third as well as a euthyroid (normal thyroid hormone level) kidney. This causes LESS uptake of radioiodine into tumors since the uptake is NOT very rapid and the rapidly diminished radioiodine in the blood impairs tumor uptake. In addition, the RELEASE of radioiodine from tumor cells is not TSH-dependent. On the other hand, the UPTAKE of radioiodine IS dependent on TSH and is diminished consequent to the rapid pulse of TSH from Thyrogen as opposed to hypothyroidism. There is certainly less radiation exposure for the body with Thyrogen use; however, there is an proportional decrease in radiation exposure to tumor cells. Since radioiodine uptake in salivary tissue has not been shown to be TSH dependent, there is no evidence nor reason to believe that Thyrogen use would diminish salivary damage.
—ThyroidCancerHelp, March, 2008
RAI therapies, intervals between
Radioactive iodine therapy causes damage to the DNA of thyroid cancer cells that have taken up sufficient quantities of radioiodine. There is an ongoing race between the cancer cell's ability to repair this DNA damage and whether the damage is severe enough to cause the death of the thyroid cancer cell. That is why very low doses of radioactive iodine can be ineffective if they produce insufficient DNA damage to prevent the thyroid cancer cell from saving itself by DNA repair. When the DNA is sufficiently damaged by the radioiodine, it might not results in the death of that thyroid cancer cell until weeks or months later when the cell attempts to reproduce by division.
The reasons for making a 5 to 6 month interval between radioactive iodine therapies is two-fold. First, there must be sufficient time to demonstrate the full benefit of previously administered treatments. Second, there must be sufficient time for the normal body parts (particularly the bone marrow) to recover so that they could safely tolerate another radioactive iodine therapy dose.
—ThyroidCancerHelp, February, 2008
RAI, taste buds after
Transient disruptions of the taste sensation (dysgeusia) are not unusual following radioactive iodine therapy. If they occur, they usually last for 3 to 6 weeks and completely resolve. There is nothing that will help with this self-limited situation except to wait it out It definitely will get better. I often suggest the idea that "every cloud has a silver lining" or to "make lemonade out of lemons." Considering how prevalent are problems with obesity, I advise my patients that this presents a wonderful opportunity to lose some weight without the concern of depriving oneself from wonderful-tasting food.
—ThyroidCancerHelp, March, 2008
RAI (tracer dose) and precautions
It's a common problem that patients are provided inappropriate recommendations and warnings regarding radioiodine that make them worried and unnecessarily anxious. Please see message #749 for extensive details regarding this issue. The 2 to 5 mCi I-131 tracer dose does not typically require any precautions aside from not sharing bodily fluids with other people (wet kissing, sex, unwashed utensils, etc.) for around 5 days. The precautions with the treatment dose are a bit more involved, but should not cause any significant hardship for most people.
—ThyroidCancerHelp, January, 2008
RAI treatment, postponing for pregnancy, breastfeeding, etc.
Diagnosis of thyroid cancer during pregnancy poses several unique logistic issues.
Breast Feeding: Please see Message #2097 and read it very carefully. If there is ANY intention or need to administer I-131 for ablation and/or scans, after birth of the child, within a minimum of 10 months, then breast feeding should not be initiated. That is because the infant usually needs a minimum of 6 months of breast feeding before being weaned, weaning takes another month, and the breasts require at least another 2 months before they are back to a completely resting state so that they do not have enhanced susceptibility to taking up radioactive iodine. Then it will take another 6 weeks to discontinue levothyroxine to prepare for I-131 treatment.
Nature of the thyroid cancer: For some patients with small papillary thyroid cancers that are not associated with bulky, invasive, or distantly metastatic disease, careful suppression of TSH to less than 0.1 (using levothyroxine), will permit the passage of 10 months after birth before I-131 treatment without any significant problem. On the other hand, there are patients with aggressive or disseminated tumors that would best be treated as soon as possible, making breast feeding a poor choice. This analysis and decision must be done between the patient and an experienced thyroid cancer physician.
Records: When moving from diverse geographies, particularly with different languages, it is critical to maintain your own copies of EVERY pertinent medical record (only relinquish photocopies to physicians; keep your own copies). A wise patient will have the pathologist cut representative slides from the original surgical tissue block so that physicians seeing them in other countries would be able to personally verify the diagnosis of the cancer before they commit to their treatment approach.
—ThyroidCancerHelp, January, 2008
Revlimid clinical trial
There are a number of on-going clinical trials utilizing a variety of new medications in an attempt to deal with different cancers, including thyroid cancer. It would be unwise (and very expensive) for patients to consider taking these experimental agents on their own, out of the context of a formal clinical trial, even though some of them are available and approved for unrelated purposes.
Strictly for the purpose of providing information, lenalidomide (Revlimid) has had very few toxic side effects in our clinical trial. They include mild depression of the bone marrow (lower white blood cells and platelets) and a higher risk of blood clots (requiring our patients to be placed on aspirin). There have been other, less common, effects; however, they are far fewer than most other experimental agents for thyroid cancer. Our current clinical trial is now just about filled up with as many patients as the protocol permits. Considering how useful this agent has been to date, I expect that there will be another trial beginning in a year or so.
—ThyroidCancerHelp, January, 2008
Risks for other cancers
It has been found that patients with cancers of ANY sort are at higher risk than the general public for getting additional different cancers. Some of this may be due to a general greater likelihood for getting cancer in such individuals, common exposure to cancer causing factors, increased vigilance by physicians to find cancers sooner than they would have otherwise, or other reasons or combinations of reasons.
Additionally, in most cancers that use chemotherapy agents, such agents are clearly related to increased risk of other cancers. In patients with all sorts of cancers getting external beam radiation, such radiation is known to increase the risk of getting unrelated cancers in the radiation zone.
In the context of all of that, radioactive iodine (despite its use for more than 60 years) has been
dramatically free of such associated risks for cancer. Over the course of several decades there have been numerous studies that have tried to see if there are such associations of radioactive iodine therapy, for either Graves' disease or thyroid cancer, and other malignancies. Most have failed to find any significant relation. If there is a new study that finds a slight statistical relationship between radioactive iodine treatment and some other cancer, it's an interesting academic finding of questionable significance, but it is clearly of no clinical value.
Radioactive iodine is used to treat clinically significant thyroid cancer. In that context, it is remarkably free of significant problems and is usually quite effective, particularly since there are no other effective systemic treatments. Would anyone seriously consider avoiding radioactive iodine therapy for an existing thyroid cancer because of a theoretical enhanced chance that there will be one additional case of breast cancer in 200,000 such patients over the course of 20 years?? I certainly hope not.
Lastly, it is wrong to worry about such studies, particularly since (as has happened many times before) it is likely to be followed by another study that refutes its conclusions in a few years.
—ThyroidCancerHelp, August, 2007
S
Salivary gland ducts, clogged
One of the potential nuisances (as opposed to dangers) of radioiodine therapy is transient or permanent damage to the salivary glands. This may result in diminished flow rates of saliva. There are a few medical consequences and solutions: 1) Decreased saliva may make eating certain foods difficult. This can be helped by using frequent small sips of water while eating. 2) Decreased salivary flow produces increased risk of tooth decay because saliva is critical to wash food particles off of teeth after eating. I advise patients to carry a small travel toothbrush kit in their pocket or purse. They should brush their teeth after EVERY meal. Sometimes this produces an added benefit by reducing between meal snacking. 3) Decreased salivary flow predisposes to "blocked salivary ducts." This refers to the swelling of one or more salivary glands (located under the ears and under the lower jaw) due to partial blockage of the corresponding salivary duct by dried saliva. This can be startling and worrisome if not recognized for what it is. I do not advocate immediate use of antibiotics unless there is fever and elevated white blood cell counts. Instead, this problem usually responds to swishing warm water (or tea, coffee, broth, etc) in the mouth while gently massaging the swollen salivary gland. Usually, there is a sudden sour taste as the stale saliva is released and the swelling goes away. If this does not work or if rapidly and frequently recurrent, then it is important to go to your physician. Usually this problem happens periodically and is then quiescent for a long time.
—ThyroidCancerHelp, August, 2007
Salivary gland swelling, long after radioiodine
As many of you know from personal experience, salivary gland damage is common after radioactive iodine therapy. It often causes the flow of saliva to become a bit sluggish. This may prompt saliva to dry inside the tiny tubes that carry saliva from the glands to the inside of the mouth (salivary ducts). When this happens, the salivary gland swells and can become quite tender. Unfortunately, many physicians mistake this for an infection. Although this can very rarely cause an infection, in the vast majority of cases, it is only a simple salivary duct blockage. In this case, antibiotics would be useless and potentially dangerous (by putting you at risk for diarrhea, pseudomembranous colitis, yeast infections, etc.).
The usual effective treatment is to swish some warm liquid in the mouth while simultaneously gently massaging the affected salivary gland. Eventually, a taste of stale and salty saliva is noted and the swelling diminishes. This may resolve spontaneously and can recur periodically. There may be several episodes in close succession, followed by several months without recurrence. Although I've seen many, many such cases, I cannot recall a single case of an infected salivary gland. Unnecessary antibiotic therapy can sometimes be dangerous.
—ThyroidCancerHelp, September, 2007
Scan prep methods: clearing up misinformation on the ThyCa listserve
[Editor’s Note: Since Dr. Ain no longer moderates the ThyCa list-serve, and there is no other medical advisor on that listserve who moderates, patient-generated advice is the ONLY advice available on the Thyca list-serve. This posting clears up considerable misinformation that was posted on the Thyca listserve which confused TCH members…]
[Regarding the misinformation circulating on the Thyca Listserve…] There are two reasons for the diminished effectiveness of Thyrogen in stimulating radioactive iodine uptake compared to hypothyroidism.
First, Thyrogen produces a transient increase in TSH over the three day period that thyroid cancer cells are exposed to it. This compares to the 10 to 12 days that hypothyroid preparation exposes these cells to an environment of high TSH values. Thyroid cancer cells do not respond to TSH instantly. It takes from hours to several days for TSH to stimulate the TSH receptors on thyroid cancer cells, send appropriate signals to the cell nucleus, turn on appropriate genes, stimulate corresponding synthesis of messenger RNA and then to translate this into proteins, such as the sodium-iodide symporter ("iodine pump") that must be transported to the cell membrane to start transporting the radioactive iodine.
Second, when a person is hypothyroid, they have hypothyroid kidneys. In such a situation, the kidneys function at one third of the rate as when the kidneys are not hypothyroid. This means that swallowed radioactive iodine is absorbed into the bloodstream and persists there long enough for cancer cells to have time to take it up. When kidneys are not hypothyroid (during Thyrogen preparation) the radioactive iodine is expelled into the urine so rapidly, that there is insufficient time for as effective uptake into tumor cells as when hypothyroid.
I've routinely measured TSH levels at the same time that I obtain thyroglobulin levels (on Day 5, after injecting Thyrogen on Days 1 and 2). I've measured TSH levels (coming from the Thyrogen) ranging from 5.0 to 110.0. They tend to average around 15 to 20. Levels are usually higher in elderly patients with diminished kidney function and lower in younger patients.
—ThyroidCancerHelp, August, 2007
Scanning strategies after thyroid surgery
A classic approach to differentiated thyroid cancer is to follow thyroid surgery with a hypothyroid/low iodine diet preparation and perform a diagnostic whole body scan. Based on the knowledge of the surgical findings and the extent of tumor demonstrated by the diagnostic whole body scan, a radioactive iodine treatment dose is given. This is followed by a post-therapy whole body scan performed 2-10 days later (I do it 2 days later) to demonstrate the extent of tumor using the treatment dose as a "super-scan dose".
Under some circumstances, the diagnostic whole body scan can be avoided and the radioactive iodine treatment dose given directly after the hypothyroid/low iodine diet preparation. For example, if the surgery demonstrates a papillary thyroid cancer under 4 cm in diameter, completely contained within the gland and a few positive local lymph nodes, it's clear to me that the patient will need at least 150 mCi I-131. With that example, the only scan might be the post-therapy whole body scan 2 days after the treatment.
On the other hand, if the tumor is invading through the thyroid capsule into surrounding tissues and/or there is already evidence of distant metastases, I plan a 5-day dosimetry study (including the diagnostic whole body scan) so that I will be able to administer a maximal possible radioactive iodine therapy dose for very aggressive disease.
There are different strategies for scanning that should be based upon the specific features of each patient's cancer. It's important to discuss the strategy with your physician to understand the approach that is used.
—ThyroidCancerHelp, September, 2007
Second pathology opinions are well worth the effort
It is NEVER a bad idea to get a second opinion on pathology (usually at a different institution and asking for a specific thyroid-cancer-expert pathologist). This is the most cost-effective way to verify that reasonable things were not missed. As an aside, the presence of multifocality (more than one tumor focus) of papillary microcarcinoma sometimes signals clinical significance and possible need for further therapy and followup.
—ThyroidCancerHelp, September, 2007
Scintigraphy and impact on RAI effectiveness
The purpose of a diagnostic radioactive iodine scan before a treatment dose of I-131 (using a "scanning dose" of I-131, measuring from 4 to 5 mCi) is to determine the extent of spread of thyroid cancer in order to provide some guidance regarding the magnitude of the treatment dosage. Under some circumstances, if the extent of disease is already known or if the nature of aggressive pathology findings (insular, tall cell, etc.) already causes the clinician to choose a therapy dose, the treatment dose may be determined and administered without a preceding scan (relying upon the post-therapy scan performed 2 to 7 days after the treatment to show the extent of iodine-concentrating tumor). Each person's situation should be individually assessed by the physician so that a rational assessment and treatment plan can be implemented.
Although a number of physicians have suggested that "stunning" of the tumor sites from the scan dose, causing a decreased ability to take up the treatment dose, may occur around 2 to 10% of the time, current studies suggest this to be much less common than that. Under circumstances when the diagnostic scan can be useful for treatment planning, it is not usually necessary to be concerned regarding "stunning".
—ThyroidCancerHelp, September, 2007
Sjogren's syndrome (effects of radioactive iodine vs.)
It is common knowledge in the thyroid oncology community that radioactive iodine therapy can cause the following problems: 1) decreased salivary gland activity, resulting in thickened and diminished saliva, often blocking the salivary ducts and causing swelling of the salivary glands; and 2) blockage of the nasolacrimal duct (the tube that carries tears from the eye to the inside of the nose.
When the nasolacrimal duct is blocked the normally formed tears accumulate in the eye (rather than draining into the nose) and cause tears to run down the face.
Sjogren's syndrome is an autoimmune destruction of the salivary glands and tear glands, causing loss of saliva and dry eyes. In such cases, the eyes are very dry and there is no excess tearing running down the face.
Many physicians are totally unfamiliar with the effects of radioactive iodine. Although they have
been taught about Sjogren's syndrome in their training, they are told nothing about radioactive iodine therapy. When confronted with unfamiliar symptoms they seek a diagnosis of what they think they know about.
A key point is that Sjogren's syndrome would result in dry eyes, not excessive tearing; whereas blocked nasolacrimal ducts from radioactive iodine would cause excessive tearing of the eyes. Thus, no matter what any antibody test reveals, the combination of excessive tearing, swollen salivary glands and decreased saliva is most consistent with the consequences of radioactive iodine. In such cases, it is highly unlikely that a rheumatologist would have any constructive contribution.
—ThyroidCancerHelp, October, 2007
SSRI use and levothyroxine
There is a class of anti-depressants known as "selective serotonin reuptake inhibitors" (SSRIs). They can be quite effective. Although there is some literature that suggests that they can interfere with the effect of orally administered levothyroxine, this effect is quite unclear. It is possible that they may alter the dose-response of the pituitary between the free T4 level and the TSH response; however, this is quite unclear and uncertain. It is also unimportant. There is no effect of SSRIs with thyroid hormone absorption into the blood.
Many patients taking levothyroxine are also treated with SSRI medications. As long as the dosage of each medication is kept constant, it is a simple matter to adjust the levothyroxine dosage so that the TSH is appropriately suppressed, regardless of the dosage or choice of SSRI medications. Do not let concerns regarding these medications interfere in their proper use, as long as they are both properly monitored.
—ThyroidCancerHelp, February, 2008
Stimulated-TG testing (frequency of)
Although a very useful document to enhance the general care of thyroid cancer patients, I do not support ALL of the recommendations of the ATA 2006 guidelines.
I have a number of thyroid cancer patients who have persistent thyroid cancer, demonstrated by I-131 scans, yet do not make detectable thyroglobulin (TG) despite hypothyroid withdrawal (TSH >30). In addition, Thyrogen stimulation of thyroglobulin is demonstrably less effective than hypothyroid stimulation of thyroglobulin (for example: Thyrogen may stimulate a TG to 4 in a patient, while a hypothyroid prep in the same patient raises the TG to 20). For these and other reasons, I do not support eliminating I-131 whole body scans (with TG assessments) and instead using only stimulated TG levels, unless the particular patient's tumor has already been shown to lack iodine uptake. The follow-up management of each thyroid cancer patients should be customized to the particular features of their particular situation.
Neck ultrasound, alone, does not provide sufficient anatomical verification of disease status. I typically add metastatic bone surveys (nuclear "bone scans" do not work for thyroid cancers) and non-contrast CT scans of the lungs. If there is reason to suspect other body sites, such as the liver, an MRI with gadolinium contrast is fine (if I am still concerned to avoid iodinated CT contrast dye).
In the typical iodine-avid thyroid cancer follow-up of a patient with negative scans and stimulated TG values, I continue to obtain scans and stimulated TG levels, although the interval between these studies grows (to a maximum of 5-yrs between hypothyroid-stimulated studies or 4-yrs between Thyrogen-stimulated studies). Some cases are not "typical".
—ThyroidCancerHelp, September, 2007
Surgeon evaluation
Adverse risks of thyroid cancer surgery; specifically, loss of parathyroid gland function or damage to the recurrent laryngeal nerves (causing vocal cord paralysis), are dependent upon a number of factors. Extensively invasive thyroid cancers pose a particular risk for these consequences. Otherwise, the risk of these consequences is related to the skill and experience of the surgeon, the extent of thyroid resection during the surgery, whether there have been previous surgical excisions in the same site, and the extent of lymph node resection.
Obviously, one would choose to decrease such risk by selecting the most skilled and experienced thyroid surgeon for the procedure. Although MOST surgeons generally claim to be highly skilled and experienced, only a few would be considered as such by careful review. Surgeons should be asked concerning the number of total thyroidectomies they perform each year (more than 30 would be desired), their own rate of hypoparathyroidism and vocal cord paralysis with their patients (also noting that ALL surgeons have some cases and sometimes highly skilled surgeons are sent the most difficult and invasive thyroid cancer cases), and their practices regarding extents of thyroid and node resections.
One way that less-experienced surgeons seek to avoid complications of surgery is to perform less-than-total thyroidectomies and to avoid removing lymph nodes. This is not the best approach. The surgical attitude regarding lymph node resection is debated and highly variable. At the very least, enlarged lymph nodes should be removed, but this may be less than optimal. Clearly, a large or invasive thyroid cancer warrants more extensive lymph node resection. A reasonable approach would be to remove lymph nodes in the central neck compartments and abnormal nodes in the same side of the neck as the thyroid tumor. If there are obviously-involved lymph nodes, more extensive lymph node resection should be performed on that side. Specific types of thyroid cancer, such as medullary thyroid cancer, mandate VERY extensive bilateral lymph node resections, sometimes taking several additional hours of surgery.
Some surgeons hold an erroneous confidence in radioactive iodine to eliminate tumor in lymph nodes. This is certainly possible for well differentiated thyroid cancers, provided that the metastatic tumor deposits are quite small; however, large deposits of tumor will NOT respond adequately to radioactive iodine. The greatest value of surgery is to eliminate as much MACROSCOPIC (the opposite of microscopic) disease as possible, enabling the greatest effectiveness of radioactive iodine therapy. It's important to discuss these issues with the surgeon and to discuss the attributes of the surgeon with the endocrinology consultant that will be working with you for your care.
—ThyroidCancerHelp, December, 2007
Swallowing (abnormal sensations while)
After a surgeon makes an incision in the neck for thyroid cancer surgery, it leaves a wound and then it becomes a scar. Inside the neck, under the scar, there is often fibrosis and internal scar tissue. The neck muscles tend to "pull" at that site and this can be perceived as an abnormal sensation when swallowing. A careful regimen of neck stretching exercises tends to diminish such sensations with time. On the other hand, it is always a good idea to report these sensations to your physician just in case there is some physical finding that suggests a different explanation.
—ThyroidCancerHelp, September, 2007
T
T4 degrades in summer heat
Unfortunately, it is very common for the TSH to rise during the summer months when patients rely upon levothyroxine to suppress their TSH. This is usually due to the significant heat-sensitivity of the pill. When exposed to temperatures warm enough to soften a chocolate bar, the hormone content of the pill is irreversibly degraded. When pills are delivered from the mail-order pharmacy and sit in the little ovens on the sidewalk, called "mailboxes", they become degraded and no longer deliver the same amount of thyroid hormone. Some solutions are: get a post-office box for your medications or don't use mail order when the weather is warm.
In regards to disclaimers about the FDA on thyroglobulin assays. This is standard practice and does not have any significant implications to patient care.
—ThyroidCancerHelp, September, 2007
Tall cell papillary cancers (invasive) need assertive treatment
With thyroid carcinomas that first are seen to be invasive, high-risk tumors at the time of initial thyroid surgery, a wise approach is to be appropriately aggressive with therapy at the very beginning. Old and out-dated customs of giving low-dose radioactive iodine ablation doses are inappropriate in the face of clearly aggressive disease.
It is impossible to separate remnant ablation from simultaneous treatment of residual thyroid cancer. In addition, such tumors are most responsive to radioactive iodine therapy early in the course of the disease, rather than later on when de-differentiated and more rapidly growing tumor cells have had a chance to proliferate and re-populate the body with cancer cells that are unresponsive to radioactive iodine therapy.
I would never give a dose of radioiodine that is lower than 200 mCi of I-131 in such a situation unless the dosimetry study shows that such a dose would exceed a safe bone marrow tolerance for that particular individual (usually an elderly person with poor kidney function) or there is already a compromised bone marrow for some other reason. Often, if a diagnostic scan is performed during the dosimetry study, patients with such tumors are found to have distant metastases (for example, in the lung). It would be highly inpillary thyroid carcinomas often fail to concentrate radioactive iodine from the very beginning or lose it early in the course of therapy. In the appropriate to give a person in that circumstance a low-dose radioiodine therapy unless treatment failure is the goal.
Finally, tall cell variant papillary thyroid carcinomas often fail to concentrate radioactive iodine from the very beginning or lose it early in the course of therapy. In the absence of known effective alternative systemic treatments for metastatic disease, initial use of radioactive iodine should be as assertive as possible. If persistent tumor in the neck is unresponsive to radioactive iodine, external beam radiotherapy is the appropriate therapy after macroscopic (as opposed to microscopic) tumor is surgically removed.
—ThyroidCancerHelp, July, 2007
Tall cell papillary thyroid cancer treatment approach
When someone has a tall cell variant papillary thyroid cancer, often seen as an aggressive tumor with invasion into tissues outside of the thyroid gland, it is treated by a total thyroidectomy with surgical removal of as much of the tumor and affected lymph nodes as possible. The next course of action would be to administer at least 200 mCi I-131 using a hypothyroid preparation and an excellent low iodine diet.
The post-therapy whole body scan (performed 2 days after I-131 administration) would be carefully examined to see if there is evidence of radioiodine uptake into tumor metastases. If so; specifically, if ultrasounds and CT scans (without contrast) or MRI scans reveal that any areas of tumor correspond completely to sites that take up radioactive iodine, then appropriate management would be to follow this treatment with further radioiodine therapies (as long as there are appropriate responses to therapy and minimal toxicity).
If, at any time, there is evidence of tumor sites that do not take up radioiodine (a common finding in tall cell cancers), then it is appropriate to consider external beam radiotherapy (XRT), particularly in regions such as the neck and only after the macroscopic tumor has been first removed by surgery. Amifostine has been used during XRT in an effort to preserve salivary function; however, preceding radioiodine may have already "fried" the salivary glands and it can have its own toxicities. [Note: amifostine should NOT be used with radioiodine since any "protective" effect on salivary glands are likely to be equally protective for thyroid cancer cells.]
I do not advocate use of XRT until we have fully gained any benefit from radioactive iodine, precisely because using XRT first is very likely to diminish the ability of the cancer from taking up any radioactive iodine.
Anyone who finds themselves with a difficult clinical situation, such as this one, should be very careful before following any clinical treatment plan that violates their understanding of this disease, unless they receive a reasonable explanation for the proposed therapy from their physician.
—ThyroidCancerHelp, July, 2007
Tall cell papillary thyroid cancers (aggressiveness of)
When certain tumor types are considered to be aggressive, it does not mean that every patient with such tumors MUST have a bad time of it. It merely means that it is more common for such tumors to behave badly. For example, although a grizzled, black leather clad motorcyclist with tattoos and shaven head may be more likely to get in a bar fight, one cannot say with distinct confidence that EVERY such person will brawl in a bar.
Tall cell thyroid cancers are, as a group, distinctly more aggressive and more likely to lose responsiveness to radioactive iodine than most other types of papillary thyroid cancers. This has not changed, but rather has been reinforced as more knowledge is gained. Any physician who states the contrary should "put up or shut up" by showing me any verifiable studies or data that contradicts 20 years of research and scholarship on this topic.
Although different pathologists have opined on the percentage of tumor cells that should appear to be tall cell in order to classify the entire tumor as tall cell, ranging from 30-50%, this may not be completely relevant. I've taken care of a number of patients whose tumors had only 5-10% tall cells, yet the metastases that were found to be growing in their lungs or bones seemed to be essentially completely tall cell papillary carcinomas. This points out that these particular cells were the components that behaved the most aggressive despite a mixed cell population in the primary tumor.
—ThyroidCancerHelp, August, 2007
Tall cell variant
Tall cell variant papillary thyroid carcinoma can occur in people of any age, although it is not usually seen in children. These tumors are usually quite large and invasive when they are discovered; although even very small tumors of this type are very significant and should be treated assertively. Many pathologists are not sufficiently skilled in evaluating thyroid cancers to be able to distinguish this type of cancer from other types of papillary thyroid cancer that may be treated differently. This is why it is often a good idea to have the slides from your thyroid cancer surgery re-evaluated by an expert thyroid pathologist.
—ThyroidCancerHelp, June, 2007
Tall cell variant papillary thyroid cancer and assertive management
Tall cell variant (TCV) papillary thyroid cancer typically shows itself as a large invasive tumor. Although some TCV tumors take up radioactive iodine, permitting the use of I-131 for scans and therapy, a portion of TCV tumors lose this ability (loss of iodine avidity) making radioactive iodine scans or therapies useless. When this occurs, it is important to use appropriate imaging studies (ultrasound, CT scans, MRI scans, PET/CT fusion studies, etc.) to find recurrent or spread tumors and to plan appropriate treatments.
When iodine-non-avid tumors recur in the neck, the best approach is usually to have an excellent surgeon remove all of the tumor that can be found and then to follow this with external beam radioatherapy (XRT). XRT works best on the tiny or microscopic tumor deposits that the surgeon must leave behind, while XRT works very poorly on "macroscopic" (large or visible) tumor deposits. This combination provides the best chance to remain free of recurrent disease and to prevent obstruction of the neck and the need for repetitive surgeries of diminishing effectiveness.
It is unfortunate that many physicians who care for thyroid cancer patients do not have this perspective, usually because they have little or no training in dealing with aggressive thyroid cancer. There is nothing more useful than a fully informed patient who is appropriately assertive to improve their care when necessary.
—ThyroidCancerHelp, June, 2007
TG antibiodies opinion
Hashimoto's thyroiditis is very common, afflicting nearly 20% of women and 10% of men. For that reason, it is very common to have coincidental thyroid carcinoma and Hashimoto's thyroiditis. One of the hallmarks of Hashimoto's thyroiditis is the production of antibodies directed against parts of the thyroid, particularly the thyroperoxidase enzyme and thyroglobulin.
Antibodies against thyroglobulin interfere with the ability of all currently known blood tests to accurately measure the actual thyroglobulin level. They tend to make the tests register a lower thyroglobulin level than actually exists. As you know, thyroglobulin levels are extremely important to ascertain the presence of thyroid cancer after a person has had a total thyroidectomy and radioactive iodine therapy. For this reason, a low or immeasurable thyroglobulin level, in the presence of anti-thyroglobulin antibodies, does not provide any confidence for the absence of thyroid cancer. On the other hand, when thyroglobulin levels are elevated in the presence of anti-thyroglobulin antibodies, particularly when these levels increase in response to hypothyroidism, this is believable evidence of the presence of thyroid cancer.
The body's immune system is carefully programmed to produce antibodies against foreign invaders, such as bacteria, viruses, and toxins. When vaccines are given to people, they consist of inactive samples of the virus or toxin which are injected to produce an antibody response from the white blood cells. These vaccine-stimulated antibodies protect the person against that specific virus or toxin. The white blood cells retain a memory regarding the production of this particular antibody, the "amnestic response," which permits them to rapidly make antibodies whenever the virus enters that person. Unfortunately, when the white blood cells endure a long period of time without seeing that particular virus, they "forget" how to make that specific antibody. That is the reason why booster shots are given to restore the vaccine's protection [for example, the tetanus vaccine].
If you understand this, you could see how a thyroid cancer cell, making thyroglobulin, can function as producing "booster shots", enhancing anti-thyroglobulin antibody production in patients with Hashimoto's thyroiditis and thyroid cancer. For those patients who are truly free of this thyroid cancer, the absence of these "booster shots" permits the memory of the white blood cells making this antibody to fade and the antibody go away.
This is the reason how we can use the persistence of anti-thyroglobulin antibodies to suggest the persistence of thyroid cancer, and the loss of these antibodies to suggest the absence of remaining thyroid cancer.
Those who wish to read further about this may download a document that I wrote as the Chair of the subcommittee on thyroglobulin for the National Academy of Clinical Biochemistry.
—ThyroidCancerHelp, June, 2007
TG levels after surgery and pediatric thyroid cancer
It takes around one month for thyroglobulin, present in the blood prior to thyroid surgery, to disappear from the blood (the half-life of thyroglobulin in the blood is approximately 65 hours). For that reason, we do not typically measure the thyroglobulin level until the time of the I-131 diagnostic scan (usually around 6 weeks after the surgery, when hypothyroid with TSH >30). Under such circumstances, it is very common to have some thyroglobulin (usually <20 ng/mL) that arises from the thyroid remnant and additional sources of thyroglobulin arising from metastatic tumor.
It is very important to remember that children with thyroid cancer have a very high incidence of distant metastases to the lung. These are typically micrometastatic, not visible on non-contrast chest CT or on MRI scans (with or without gadolinium). Under the circumstances when lung metastases are found, concentrating radioiodine but not visible on CT scans, they are usually highly responsive to high-dose I-131 therapy (if administered properly).
—ThyroidCancerHelp, February, 2008
Thymus gland
The thymus is a structure in the anterior mediastinum (the center of the chest, just under the thyroid bed) that is part of the immune system. This organ contains T-lymphocytes and is most needed during infancy and early childhood. By adulthood, this "gland" has involuted (shrunk) and is generally of little further use to the immune system. In many adults, there is sufficient residual thymus gland to be identified and seen on diagnostic xray studies. The thymus may also "light up" on PET scans, even though it does not contain tumor. The thymus gland does NOT take up radioactive iodine; however, it may be in close association with lymph nodes that contain metastatic tumors that take up radioactive iodine.
—ThyroidCancerHelp, November, 2007
Thymus gland and PET scans
The thymus gland is known to take up FDG and show as a "positive" uptake site on a PET scan. For that reason, it is nearly impossible to state definitively whether FDG uptake at this site represents a normal finding or thyroid cancer metastases.
Having used PET scanning in the "early days" before it was known that the thymus can show FDG uptake, I can tell you that a young lady, my patient, with an elevated thyroglobulin level but negative I-131 scans revealed uptake on the PET scan in the thymus. Because of this, a thoracic surgeon split her sternum to operate on that tissue. The patient was "fortunate" in that her thymus contained 3 lymph nodes with papillary thyroid cancer and the surgery proved to be successful and useful. On the other hand, if that situation were to occur today, with a PET scan positive thymus gland, I would not have suggested such surgery. It's not simple nor easy and I don't aim to rely upon "luck". More investigation and improvement in our methods is needed.
—ThyroidCancerHelp, September, 2007
Thyrogen scan protocol
The standard protocol used for I-131 scans using a Thyrogen preparation is as follows:
1) Initiate a Low Iodine Diet 2 weeks prior to the scan week.
2) Scan Week: Day 1 and Day 2: inject Thyrogen 0.9 mg IM.
3) Day 3: Pregnancy test (if appropriate), then I-131 tracer dose (should be AT LEAST 4 mCi).
4) Whole body scans (I perform them on Days 4 AND 5, but some do them on Day 5 only).
5) Day 5: thyroglobulin level AND thyroglobulin antibody level.
6) Discontinue the Low Iodine Diet after the scan on Day 5 is completed.
—ThyroidCancerHelp, June, 2007
Thyrogen symptoms
Thyrogen is recombinant human TSH. When injected into a person who has had their thyroid removed, it does not cause any change in thyroid hormone levels. TSH levels typically return to their pre-injection level by 10—12 days after the last Thyrogen injection. Although there may be transient and unusual symptoms from a Thyrogen injection (chest pressure, "fluttering" sensation, etc.), these are completely resolved by 1—2 days after the last injection.
Thyroid cancer patients on the minimally sufficient levothyroxine to maintain an appropriately suppressed TSH (0.1 or less) may still have some thyrotoxic symptoms, such as racing pulse, palpitations, and "panic" attacks. These respond VERY well to beta-one-selective beta-blockers. For further discussion, please see messages: #1044, #2319, and #2518.
—ThyroidCancerHelp, March, 2008
Thyrogen vs. hypothyroid prep
The statistics quoted regarding the "effectiveness" or "accuracy" of Thyrogen scans are not valid and quantified values are not likely to be reliable. The general perspective is that hypothyroid preparation provides more sensitive scan results than using Thyrogen. Under some circumstances, Thyrogen is appropriate preparation, but under other circumstances it is best use a hypothyroid preparation. As far as being concerned whether hypothyroidism promotes growth of thyroid cancer cells, this is not of concern if these cells take up radioactive iodine and will be killed by administration of a therapeutic I-131 dose. On the other hand, it is not appropriate to do diagnostic scans with hypothyroid preparation if there is no intention to treat or if the cells no longer take up radioactive iodine. Common sense is very necessary.
—ThyroidCancerHelp, November, 2007
Thyroglobulin, alone, is not sufficient follow-up
The appropriate follow-up testing for thyroid cancer patients must be individualized for the type of thyroid cancer, its extent and response to therapy and for a variety of other factors. That being said, I am also in disagreement with those physicians who advise stimulated (with Thyrogen) thyroglobulin levels for follow-up without I-131 scanning. I prefer to use combined diagnostic modalities, including judicious use of nuclear studies, radiological studies, blood tests and physical examinations to verify the status of my patients.
—ThyroidCancerHelp, September, 2007
Thyroglobulin and negative post-radioiodine therapy scans (approach to elevated)
When unsuppressed thyroglobulin levels are high, in a patient with a total thyroidectomy for thyroid cancer who has been treated with radioactive iodine, it signifies persistent thyroid cancer. If a therapeutic dose of radioactive iodine demonstrates a negative post-therapy whole body scan (a few days after the I-131 dose) and the follow-up unsuppressed thyroglobulin is still similarly elevated, then one should check to make sure that there had not been interfering stable (non-radioactive) iodine (such as from CT contrast dye) that could have interfered with the uptake of the I-131.
If such interference is ruled out, this clearly reveals the tumor cells to be unresponsive to(not able to take up) radioactive iodine. Under these circumstances, it is not at all useful to give further I-131 therapy.
People in such circumstances should utilize different approaches to find the site(s) of their cancer to address treatment options. These different approaches include: ultrasound, CT scans (now using contrast since radioiodine is no longer a consideration), MRI scans, PET scans, x-rays, etc. The approach to this cancer is based upon the results of the search. Should the search prove ineffective, the patient can be reassured that undetectable tumors are unlikely to harm them and that the search would continue at appropriate intervals until the tumors are found.
—ThyroidCancerHelp, October, 2007
Thyroglobulin and TG-antibody tests (interpreting)
It works this way:
1) The only cells in the body that have been found capable of producing the thyroglobulin protein are thyroid cells or cancers that came from thyroid cells.For that reason, the presence of any measurable thyroglobulin in the blood, after a person has had a thyroidectomy and appropriately administered radioactive iodine therapy, signifies the persistence of thyroid cancer cells in the body. There are no documented exceptions.
2) Laboratory assays to measure thyroglobulin protein or anti-thyroglobulin antibodies that are in the blood, have defined thresholds of sensitivity, defined zones of "ambiguity", and defined statistically-derived performance features that differ between assays produced by different companies and using different assay methods. It is important to know the precise characteristics of the assay that is used for a particular test in order to interpret it appropriately.
For example: one particular thyroglobulin assay has a sensitivity threshold of 0.5 ng/mL blood. Another assay has a sensitivity threshold of 0.1 ng/mL. It is very likely that a "detectable" thyroglobulin in the second assay (of 0.4 ng/mL) would be "undetectable" in the first assay. It is even more complex than that simplistic example, since there is no necessarily direct correspondence of nanograms of thyroglobulin measured in any one assay with the level measured in another assay, even if the level is in the same detectable range for each of the assays. That is why you must compare sequential thyroglobulin measurements over time using the exact same assay if you want to make strict numerical comparisons.
The antithyroglobulin antibody tests do not work like some might suppose. These tests usually measure parameters that include a "normal range," meaning that it is not so simple as supposing that "0" equals "no antibodies" and any number above that equals "some" antibodies. Rather, one has to know the precise "normal range" for each particular assay if you wish to see if your result represents a number higher than this range (consequently "positive" antibodies) or not.
3) Finally, it should be understood that some tests are far more sensitive than others. For many patients, thyroglobulin elevations precede the ability of radiological tests to show the locations of the tumors. Likewise, for those tumors capable of taking up radioactive iodine, whole body scans can reveal tumor cells infiltrating the lung when the most sensitive Chest CT scan cannot reveal them. It pays to be informed.
—ThyroidCancerHelp, November, 2007
Thyroglobulin antibodies and the "normal range"
It is often confusing to interpret laboratory results. Typically, the "normal range" that is shown can be interpreted as meaning that a value within that range is normal and does not indicate the presence of a problem. In reference to antibody "normal ranges" a value within this range suggests the absence of clinically significant antibodies. Since these tests are very different from different laboratories, it's often best to check with the laboratory.
On the other hand, for some things (such as thyroglobulin), the normal range is NOT meaningful. That's because the normal range for thyroglobulin is usually meant to mean the normal range of thyroglobulin for healthy individuals with intact thyroid glands. Such a normal range is meaningless for thyroid cancer patients without thyroid glands. For such patients, any measurable thyroglobulin is abnormal (no matter what the normal range says) and we seek a thyroglobulin as low as possible.
—ThyroidCancerHelp, October, 2007
Thyroglobulin assay sensitivity and the effect of TG-antibodies
In most commercial thyroglobulin (TG) assays, the effect of TG-antibodies is to cause the measured level to appear lower than it truly is. That means, for example, an actual TG level of 10.0 will appear to be (perhaps) 2.0 if there are sufficient levels of TG-antibodies. In such cases, any measurable TG in the presence of TG-antibodies would be considered to be higher than desirable and likely signal the presence of persistent thyroid cancer.
In addition, different commercial laboratories use different TG assays. Each assay has its own inherent sensitivity. Some assays can only measure TG to 3.0 and anything under that number is reported as "less than" 3.0. Some assays can measure down to 0.1. Newer assays are under development that may be able to measure down to 0.01. Certainly, as TG assays become more sensitive, some people will be discovered to have persistent thyroid cancer who thought that they were free of it using an older TG assay. This is the usual situation when laboratory tests become more sensitive.
—ThyroidCancerHelp, July, 2007
Thyroglobulin checks in first year
The effects of radioactive iodine therapy take 3 to 5 months to fully manifest themselves in regards to tumor cell death. In addition, it is useful to permit the bone marrow at least 5-6 months to recuperate from the effects of a previous radioactive iodine treatment. To that end, getting thyroglobulin results prior to the coincidence of timing that accomplishes the complete effects of the previous treatment and enables one to be ready for another treatment, if necessary, is likely unnecessary. Typically, we recheck (with hypothyroid preparation and low iodine diet) an I-131 whole body scan and stimulated thyroglobulin around 6 months after a previous treatment.
—ThyroidCancerHelp, September, 2007
Thyroglobulin immunohistochemistry (positive)
The presence of thyroglobulin in a tumor cell, as shown by appropriately performed and verified immunohistochemistry, is definitive proof that the tumor cell is a thyroid carcinoma. It DOES NOT define whether it is a papillary cancer, follicular cancer, or any particular variant thereof.
—ThyroidCancerHelp, September, 2007
Thyroglobulin levels after surgery and before RAI
We do not typically measure thyroglobulin levels after thyroidectomy, until the patient is prepared for I-131 scan and therapy. Circulating thyroglobulin in the blood has a mean half-life of 65 hours, meaning that it will take at least a full month for the thyroglobulin that was present in the blood before the thyroid surgery to be cleared from the blood. After that time, the thyroglobulin level will be dependent upon a combination of factors: the size of the remnant, the extent of metastatic disease or residual tumor, the TSH level, the degree of differentiation of the cancer (aggressive and poorly differentiated cancer make less thyroglobulin per gram of tumor), the presence of interfering autoantibodies, etc. For that reason, there is no simple answer to the question. Obviously, a thyroglobulin of 1000 ng/mL without interfering antibodies would be alarming, but extreme values always are. Thyroglobulin is MOST useful after surgical thyroidectomy and radioactive iodine ablation has been performed at least 6 months in the past and the patient is prepared with an elevated TSH (by hypothyroid withdrawal, most sensitive, or Thyrogen).
—ThyroidCancerHelp, January, 2008
Thyroglobulin levels (persistent)
When I-131 scans are negative, it is important to discern whether thyroglobulin values (when stimulated by hypothyroid withdrawal or Thyrogen) are sufficiently elevated so as to reflect persistent thyroid cancer. The level of thyroglobulin that is significant varies greatly, depending upon the particular assay method that is used by the particular laboratory. In some cases, this can vary from 0.4 to 2.0 using different assays.
If the thyroglobulin IS significantly elevated, then there are a sequence of possible approaches. Often, we will prepare the patient using hypothyroid withdrawal and low iodine diet, then administer a therapeutic I-131 dose (usually at least 150 mCi) and evaluate the 2-day post-therapy whole body scan. Sometimes we see evidence of tumor sites on this scan that denote residual tumor sites and suggest the likelihood of benefit from the treatment. Sometimes, although the scan may be negative, subsequent stimulated thyroglobulin levels are much lower, providing evidence of the benefit from that I-131 treatment. On the other hand, if the scan is negative and the thyroglobulin has not responded, then it is important to maintain suppression of the TSH with sufficient levothyroxine and initiate a systematic radiographic evaluation to seek any macroscopic sites of tumor.
Thyroglobulin levels with tumor response (correlation of)
When dealing with metastatic thyroid cancers it is easy to develop tunnel vision. Thyroglobulin levels reflect tumor in the entire body, not just at any single site. If the thyroglobulin elevation is not explainable by a tumor response at any particular site in the body, it is important to expand your view to other sites that may also have deposits of thyroid cancer and were previously unnoticed.
The evaluation of the entire body for sites of tumor is called "tumor staging". If the thyroid cancer is well documented to no longer take up radioactive iodine, then the technique to evaluate the entire body can be using CT scans with contrast. Additionally, PET scans (often enhanced by Thyrogen stimulation) can be useful, but are not usually definitive.
—ThyroidCancerHelp, September, 2007
Thyroglobulin (persistent) indicates persistent thyroid cancer
For patients with differentiated thyroid cancer, having had a total thyroidectomy and post-surgical ablation of residual tissue with radioactive iodine therapy, an elevated thyroglobulin indicates residual thyroid cancer, even if the radioiodine whole body scan is negative. This was described in a paper I co-authored more than a decade ago [Pineda JD, Lee T, Ain KB, Reynolds JC, Robbins J. 1995 Iodine-131 therapy for thyroid cancer patients with elevated thyroglobulin and negative diagnostic scan. J Clin Endocrinol Metab. 80:1488-92.].
As shown in the JCEM article referenced above, my practice is to treat such patients with a large dose of I-131 (> 150 mCi). Most such patients respond by showing a positive post-therapy whole body scan (taken after release from the isolation room) and subsequent decline in the thyroglobulin level. Radioactive iodine treatment, in this fashion, can be effective at nearly any soft tissue site (aside from bone). The fact that CT scans and MRI studies cannot see a macroscopic lesion makes it even more likely that micro-metastases can respond to this therapy. It is important to make certain that iodinated contrast dye has been avoided so that the radioiodine can maintain its effectiveness.
For those patients without such a beneficial response, the practice is to search for radiographic evidence of dedifferentiated tumor with CT, MRI, and/or other nuclear scans (PET scans, etc.) in order to find disease which is potentially removable by surgery. I (and other investigators) am actively investigating a variety of strategies for "re differentiation" therapy, but this is still very experimental. Otherwise, if a site of disease cannot be identified, these patients are maintained on suppressive levothyroxine therapy and periodically re-evaluated to attempt to identify disease sites.
It should be noted that some sites, particularly in breast tissue, may "light up" on I-131 whole body scan yet may not be sites of thyroid cancer. Sometimes breast cysts have radioactive iodine that has collected in the cyst fluid and falsely appears to be thyroid cancer. Rarely, some breast cancers may appear to take up some radioactive iodine.
Sometimes, the approach with radioiodine therapy is ineffective in reducing the thyroglobulin. Over the past 15 years, I've lectured at many venues regarding the clinical approach towards dealing with thyroid cancer that does not take up iodine. Many patients are referred to me for this particular problem and I've developed a number of approaches towards dealing with it. Some of these approaches are summarized in the following publication:
Ain KB 2000 Management of undifferentiated thyroid cancer. Baillieres Best Pract Res Clin Endocrinol Metab 14:615-29. (http://www.ncbi.nlm.nih.gov/pubmed/11289738)
—ThyroidCancerHelp, August, 2007
Thyroglobulin test (timing of) after Thyrogen
The most potent way to stimulate thyroglobulin levels to their utmost is by becoming hypothyroid with TSH values above 30. Thyrogen is not quite as effective at stimulating thyroglobulin levels; however, it is necessary to provide sufficient time for any thyroid cancer cells to respond to the Thyrogen injections. When injecting Thyrogen on Days 1 and 2, thyroid cancer cells will not be sufficiently stimulated to make thyroglobulin until Day 5.
—ThyroidCancerHelp, July, 2007
Thyroid antibody tests
There are two antibody tests that have proven clinically useful for evaluating autoimmune thyroid disease (Hashimoto's thyroiditis). They are: anti-thyroperoxidase antibody (aka, anti-microsomal antibody) and anti thyroglobulin antibody. These are used ONLY for evaluating for autoimmune thyroid disease.
The only use of any of these tests for thyroid cancer is the "anti-thyroglobulin antibody" test (TG-Ab). This is only done to validate the thyroglobulin level as being free of antibody interference (if the TG-Ab is negative). The TG-Ab level generally will fall over time, if originally elevated, if the person is free of thyroid cancer cells for at least 2 to 3 years.
—ThyroidCancerHelp, August, 2007
Thyroid cancer and diabetes
Patients with Type 2 diabetes mellitus typically have had elevated insulin levels for several years, due to insulin resistance, before their pancreas can no longer compensate and blood sugars begin to rise. Obesity is one cause of this insulin resistance that is able to be altered by patients to reduce their insulin resistance, sometimes to the point that they no longer require medications to control their blood sugar.
There is no direct relationship between development or worsening of diabetes mellitus and thyroid cancer. Sometimes, the increased attention to health that comes from a new diagnosis of thyroid cancer uncovers previously unrecognized problems such as diabetes. Sometimes, as life and health progress, there is the coincidence of both developing near the same time. Poorly controlled or managed diabetes mellitus can sometimes pose a far greater risk to health and survival than some cases of thyroid cancer. There are even rare circumstances where a morbidly obese patient with hypertension and uncontrolled blood sugars has been put on a "thyroid cancer sabbatical" by me, in which I delay their thyroid cancer therapy indefinitely until they get a handle on far more dangerous and pressing issues of health that they have too long ignored. The bottom line is to avoid the "tunnel vision" of being concerned about "CANCER", even when minor, yet ignoring other health concerns that are likely to be far more lethal.
—ThyroidCancerHelp, December, 2007
Thyroid cancer and estrogens
There is no ill effect of estrogen replacement therapy in regards to thyroid cancer. If any woman is discovered to have thyroid cancer, this is not a reason to discontinue or avoid estrogen therapy.
On the other hand, the risks and benefits of estrogen therapy are still being determined and the decision whether to take estrogens is a complex issue based on many factors. Fortunately, the presence of thyroid cancer is not one of those factors.
—ThyroidCancerHelp, September, 2007
Thyroid cancer and growth of children
The pituitary gland is regulated by the hypothalamus in the brain and by feedback signals from other endocrine glands. Sometimes, there are deficiencies in certain hormones, such as growth hormone, that are singular and not related to defects in other pituitary hormones. The interactions between pituitary hormones and other hormones, such as thyroid hormones, are fairly well defined (but we are always learning more).
In the specific case of thyroid hormone effects upon growth hormone, it is well known that the gene for growth hormone is turned off when a young child is significantly hypothyroid. This is part of the reason for the short stature of children born without sufficient thyroid hormone who are not given thyroid hormone treatment. It would be very unlikely that such hypothyroidism could be missed during the endocrine evaluation of a child with short stature.
I have seen many children with thyroid cancer and have never noted a specific relationship between their thyroid cancer (no matter how aggressive) and their ability to achieve appropriate stature. It's always interesting to speculate; however, the more that one understands about the processes involved, the more difficult it is to accept simplistic explanations.
—ThyroidCancerHelp, October, 2007
Thyroid cancer and risk of other cancers
For papillary thyroid cancers, a key issue is multifocality. That refers to the presence of more than one site of papillary thyroid cancer within the thyroid gland, regardless of the size of each of the tumors. Multifocality of papillary thyroid cancer, in my opinion, is an appropriate reason to follow the thyroidectomy with radioactive iodine scanning, therapy, and long-term follow-up. This is because the multifocality seems to be a sign that there is a reasonable chance that the tumor cells have already spread beyond the location of the thyroid gland, long before the thyroid has been surgically removed. Patients with such multifocal papillary thyroid cancers are not usually sufficiently treated with just thyroid surgery.
The recent study that is being referred to, addressing second primary cancers in patients with thyroid cancer, found an increase POPULATION risk of second cancers in the entire thyroid cancer group, regardless of whether they had received radioactive iodine or not. There was an increased risk in those that received radioactive iodine; however, this risk was only significant for a short period of time (likely too short to be consequent to the radiation) and was not consistent with known exposures of the specific body sites to the radioactive iodine. Although these results are interesting and speculative, they are not at all definitive and do not clearly show the cause of this association.
On the other hand, these POPULATION risks (not necessarily applicable to definable INDIVIDUAL patient risks) of minimal and indefinite nature, must be balanced against the risks of NOT TREATING a known existing thyroid cancer. All of life is a balance of risks and benefits. For those who want easy answers and no risks at all, only read books in the fiction section of the library.
—ThyroidCancerHelp, February, 2008
Thyroid cancer breast masses
Although I have seen thyroid cancers metastasize (spread) to every conceivable spot in the body, including the breasts, specific spread to both breasts is highly unusual. Most likely for consideration would be benign or malignant primary breast disease. There is no role for guessing. The only appropriate course would be to get biopsy any breast lesions to see what they are. It is not unusual for some people to have more than one cancer at a time.
On the other hand, should the biopsy be performed (with immunocytochemistry performed to see if they contain thyroglobulin) and the cells in the breast nodules stain positively for thyroglobulin (proving them to be thyroid cancer metastases) then the recent radioactive iodine scans should be examined to see if the breast nodules had taken up radioactive iodine. This would have importance regarding further treatment options after surgical therapy.
—ThyroidCancerHelp, August, 2007
Thyroid cancer (competency in treating)
Primary care physicians do not typically receive sufficient training regarding thyroid cancer to render appropriate or competent care, without the contribution of a specialist (usually an endocrinologist). Thyroid cancer is a disease that requires special expertise. Some endocrinologists are not sufficiently skilled. Unfortunately, such training and expertise is also not typically seen with most oncologists. Having been a member of an Oncology Division at an academic medical center, having lectured many times to oncology groups and meetings, and having authored chapters on thyroid cancer in several oncology textbooks, I can vouch for the lack of training regarding this disease in that specialty. Some oncologists make up for this deficiency with self-education, but most do not.
No one should consider themselves "enslaved" to their primary care physician and should vote with their feet if they are uncomfortable with the competency of their care. They may also voice concern with a facility’s medical director if the physician is part of a larger group. Some people are in national healthcare systems (in different countries) that give their primary care physician powerful "gate-keeper" roles. There are likely avenues for similar problems in such systems. The general rule is "the squeaky wheel gets greased." It's very important to function as an active advocate of your own healthcare.
—ThyroidCancerHelp, October, 2007
Thyroid cancer follow-up
First, appropriate follow-up. after I-131 ablation after thyroid cancer surgery, should entail both functional and anatomical studies.
Functional studies include repeat I-131 scanning and stimulated (by hypothyroidism or Thyrogen) thyroglobulin levels. There should be a documented "clean" I-131 whole body scan. The measured thyroglobulin levels should not be "normal", according to the printed "normal range", but rather should be undetectable (as close to "zero" that the assay will permit). The "normal range" is intended for people who have their thyroid glands and do not have thyroid cancer. "Normal" for thyroid cancer patients is NO thyroglobulin measurable. Likewise, since thyroid cancer patient should keep their TSH suppressed, rather than in the "normal range", a "normal" TSH for a thyroid cancer patient is <0.1.
Anatomical studies should be appropriate and sensitive for the presence of thyroid cancer metastases and, if the tumor has lost any functional properties (radioactive iodine uptake or thyroglobulin production) may be the only indicators of recurrent or progressive disease. They should be performed so that they DO NOT interfere with functional studies (such as radioiodine uptake) if those studies are planned within the year.
Evaluation with tomographic scans can be performed with MRI studies using gadolinium as contrast (since gadolinium does not contain iodine). In body regions, such as the head, neck, abdomen and pelvis, gadolinium contrast is usually necessary and is fine. In the chest, a CT scan (WITHOUT ANY CONTRAST) gives the best resolution. [Note: ALL CAT scan dye contains high levels of non-radioactive iodine and will interfere with radioactive iodine or therapy for 2 to 12 months (length of time is NOT predictable)] Evaluation of the neck can also be performed using an ultrasound with an experienced person. I prefer that any suspicious areas seen on an ultrasound be biopsied (fine needle aspiration technique) at the time that they are first seen on the ultrasound.
There are many ways that physicians can adjust their methods of evaluation so that they do not interfere with the care of their patients. Sometimes they are ignorant of these issues and sometimes misinformed.
—ThyroidCancerHelp, July, 2007
Thyroid cancer (genetic risk of)
Although it is clear that a minority of people with papillary thyroid cancer have a hereditable component to their disease, the specific gene mutations associated with this have NOT yet been definitively identified and the penetrance (likelihood that the cancer will occur if the mutations are present) and the mode of inheritance (dominant or recessive, autosomal or sex-linked) have NOT been defined. For that reason, there is no way to evaluate or screen family members for this particular possible risk.
If there is a distinct family history of papillary thyroid cancer, at least three first-degree relatives with this disease, then it seems reasonable for other family members to make certain that a careful physical exam of the thyroid gland is part of their annual physical evaluation by their primary care physician (although many physicians are quite incompetent in such exams). Any suggestion of a "lump" or question of abnormality should be further evaluated by thyroid ultrasound. Any nodule that is found to be larger than 1.0 centimeter should be evaluated by fine needle aspiration biopsy. There are no blood tests that would prove useful for such evaluations.
The issue is completely different for patients with MEDULLARY thyroid carcinoma. Nearly one third of the time, there is a specific gene mutation in the RET proto-oncogene that is responsible for this cancer. Anyone with this cancer must have their blood checked for this mutation. If the mutation is present, it is inherited as an autosomal dominant trait with nearly 100% penetrance. That means that other family members (and often extended family members that are blood-linked) should have their blood tested for this mutation. If the mutation is positive, it is recommended that the person's thyroid be prophylactically removed as soon as possible, even in ages as young as 2 years. Please note that this recommendation ONLY applies to MEDULLARY thyroid cancer.
—ThyroidCancerHelp, October, 2007
Thyroid cancer: how fast does it grow?
Thyroid cancers can grow at extremely different rates. For that reason, it is nearly impossible to back-calculate, based on a tumor's size, how long it had been present.
Anaplastic thyroid cancer (ATC) cells grow the most rapidly. I've had patients with ATC tumors double in size every 2 to 3 days, going from a golf ball size to a melon size in just a week. That is extremely fast, although most ATC tumors grow at a much slower rate than that.
Papillary microcarcinomas (typical papillary cancers less than one centimeter in diameter) are found in many peoples' thyroid glands after death from other causes. This likely makes them the slowest growing cancers since they probably remained this size for sometimes several decades.
Some patients are found to have thyroid cancers in thyroid masses that had been present, without change in size, for many years. Presumably, these masses had been very slowly growing for some time. On the other hand, some papillary cancers seem to grow quite rapidly (doubling in size each month or two). This is particularly common in aggressive insular thyroid cancers or in some aggressive types of papillary cancers, such as tall cell variant.
Thyroid cancers may change their rate of growth dramatically. The classic situation is that of a slow-growing papillary cancer, present without apparent change for several years in someone's neck (thought to be a "goiter"), then suddenly growing very rapidly as a subset of its cells mutate and change to an ATC.
For this reason, it is very difficult to predict the rate of growth of a thyroid cancer, merely based upon the size it is discovered to be at the time of surgery.
—ThyroidCancerHelp, June, 2007
Thyroid cancer, how it spreads
A common question relates to the tendencies of different types of thyroid cancer to spread (metastasize) to different sites. The general situation is that papillary cancers (all types) tend to travel through the lymphatic vessels and grow in lymph nodes, while follicular cancers are most likely to travel through the bloodstream, going to lung, liver, bone, brain, etc. As in most generalities, the exceptions are very common. Although follicular cancers are more likely to spread to the lung, there are 8-fold more papillary cancers and it ends up that most lung metastases of thyroid cancer come from papillary thyroid cancers. Likewise, papillary cancers can go to bone, liver, brain, etc. I have a couple of patients with Hurthle cell thyroid cancer that has spread to their retina (eye), as well as a number of papillary thyroid cancers that have done the same. The bottom line is that ANYTHING is possible. The best that we can do is to aim for optimal treatment and optimal follow-up, combined with a healthy lifestyle and a lot of hope/faith. Fortunately, that works well for most people.
—ThyroidCancerHelp, December, 2007
Thyroid cancer in children
It is always very difficult to accept the fact that young children can get thyroid cancer. Although less common than in adults, when children get thyroid cancer (usually papillary) it is often more aggressive in its growth and spread than in adults, frequently spreading to the lungs and bones. Fortunately, it is often very responsive to radioactive iodine therapy, provided that meticulous care is taken in preparation, dosing, and follow-up.
Besides these issues with the cancer itself, there are also other problems particular to children.
It is VERY important that levothyroxine be given with precision and reliability to suppress the TSH. Children are often non-compliant with medications. I've had parents find piles of thyroid tablets spit out behind their kitchen refrigerator. Sometimes, physicians are inexperienced with finding the proper dose. Suppression doses of levothyroxine could keep children from sleeping and make them severely tired during the day. This could also contribute to gastrointestinal problems. Careful dose adjustment and use of a beta blocker medication can be an answer.
It is a common mistake to think that "bricks treat patients rather than physicians." That means that sometimes famous and prestigious institutions are presumed to provide the best care for every medical problem and patients go there assuming that this is what they will get. The reality is that specific experienced physicians are the best sources of care. They may be located at prestigious institutions or may be in less well known hospitals. It's better to seek out the particular rare physician with experience in pediatric thyroid cancer, rather than presume that every hospital has equal expertise.
—ThyroidCancerHelp, June, 2007
Thyroid cancer patients are NOT hypothyroid at normal TSH levels
Thyroid cancer patients are exactly like every other hypothyroid patient in regard to symptoms of hypothyroidism. When the TSH is NORMAL (0.5 to 3.0, depending on the lab) there should be no symptoms that are ascribable to hypothyroidism. The only exception is someone with pituitary or hypothalamic disease.
The reason for thyroid cancer patients to keep their TSH less than 0.1 is to prevent normal levels of TSH from stimulating any thyroid cancer cells that may have survived treatment. It is NOT done because thyroid cancer patients have hypothyroid symptoms with normal TSH values (they don't).
—ThyroidCancerHelp, August, 2007
Thyroid cancer (pediatric) and delay in diagnosis
When thyroid cancer occurs in children, the tumor is very often quite advanced, being large and profusely metatastatic in the neck. In a large portion of these children, the tumor has metastasized to the lungs by the time that the initial thyroid surgery has been done. The only saving grace is that their cancers are usually quite responsive to radioactive iodine when appropriately used.
It is impossible to predict at which stage of growth the primary tumor (in the thyroid gland) takes advantage of the lymphatic vessels to spread to lymph nodes in the neck. It is possible, but unable to be proved, that such spread has already occurred by any time that the primary thyroid tumor becomes large enough to feel. It is unfortunate that some physicians do not attend to thyroid masses promptly, but, in the case of childhood papillary carcinomas, it is important to know that a total thyroidectomy is warranted (as well as appropriate neck dissection for lymph nodes), anytime the primary tumor exceeds 1.0 cm in diameter or has spread outside of the thyroid gland.
Parents of children with metastatic thyroid cancers should be certain that they make use of endocrinologists with particular expertise in the management of thyroid cancer. Most pediatric oncologists do not receive such training. The most important issues lay in front of us in such cases, not behind.
—ThyroidCancerHelp, August, 2007
Thyroid cancer, pediatric diagnosing
Diagnosing thyroid cancer in a child is not very different from doing so in an adult. Physicians should evaluate any thyroid nodules or neck masses with a fine needle aspiration biopsy. This can be done easily in children without any significant risk and without any significant discomfort (if the physician is sufficiently skilled).
Children are more likely to have enlarged lymph nodes in the neck from temporary infections in the ears or mouth. One common problem is that pediatricians tend to treat these nodes with antibiotics for extended periods of time instead of performing a biopsy. A reasonable approach is to biopsy any lymph nodes that persist for more than 2 weeks, particularly in the absence of any known local infection that could be responsible for a benign inflammatory cause.
It is not too uncommon for a child to have an enlarged thyroid gland (a goiter) from benign causes, usually due to Hashimoto's thyroiditis (unless the child is in Africa or South America where the cause could be iodine deficiency, not seen in the US). If the thyroid enlargement is diffuse, meaning that the enlargement is over the entire gland symmetrically without any nodules or predominance of any specific part of the gland, then it is not unreasonable to monitor the child (and treat with levothyroxine if the TSH is at all elevated). It is often difficult to exclude a thyroid nodule by physical examination alone and the ultrasound is a useful test to do.
Should there be any of the following, it would be very reasonable to have a fine needle aspiration biopsy performed: 1) identification of one or more distinct nodules exceeding 1.0 cm in diameter, 2) identifiable (or developing) asymmetry of the goiter, 3) progressive increase in the size of the goiter (particularly when the TSH has not been elevated), or 4) development of any enlarged lymph nodes in the neck while the goiter is still present (in this case, biopsy the lymph node AND the goiter).
It is hard to avoid feeling anxious for one's child, particularly when a parent is a thyroid cancer patient themselves. Knowing that their pediatrician has a reasonable plan to monitor their child's thyroid gland, utilizing non-invasive ultrasounds at reasonable intervals and having a low threshold for performing fine needle aspiration biopsies when appropriate, should alleviate such anxiety.
—ThyroidCancerHelp, August, 2007
Thyroid cancer risk, PET Scan, and bone marrow function
In the TNM classification of thyroid cancers, those that invade through the capsule of the thyroid gland are considered a T3 or T4 tumor, based upon how extensive the extra-thyroidal invasion. In neither of these possibilities is the tumor considered "low risk" by anyone with even a miniscule degree of expertise in thyroid cancer treatment.
As previously stated, those thyroid cancers with greater uptake of FDG (seen as a brighter image on a PET scan) are those with greater metabolic rates and more aggressive behavior.
Although radioactive iodine therapy may be appropriate or may not be, based upon the results of I-131 scans, thyroglobulin levels and the results of anatomical imaging (ultrasounds, non-contrast CT scans, MRIs with contrast (gadolinium will not affect iodine uptake)). The evidence for persistent thyroid cancer based upon these studies is balanced against the risk of therapy (such as impaired bone marrow function).
On the other hand, anyone with impaired bone marrow function would warrant appropriate evaluation with folate, B12 levels, bone marrow biopsy, and other appropriate studies that a hematologist might suggest. Abnormalities of bone marrow function SHOULD be investigated before they are blithely accepted without question.
—ThyroidCancerHelp, January, 2008
Thyroid cancer research
[There] are MANY clinical trials that utilize a variety of new and old agents. These can be accessed at www.cancer.gov/clinicaltrials. There you will see both my clinical trials and those of other researchers. In addition, my laboratory and many others are engaged in many basic research projects in thyroid cancer (my lab has been involved in this for nearly two decades). One can seek reports regarding this research through the PUBMED search engine at the National Library of Medicine.
A much greater problem with longer range consequences is the current failure (particularly in the USA) to support research in thyroid cancer. The entire National Institutes of Health budget has been severely hurt by misguided policies in Iraq with resulting fiscal starvation of researchers to pay for military misadventure. My own laboratory has been hard hit by this situation and many of my colleagues have closed down their laboratories and discontinued research efforts that could of had great benefit. When federal funding of research becomes inadequate, there are only two alternatives: pharmaceutical company support (usually product-driven and not supportive of basic research) and charitable gifts. The lack of interest in thyroid cancer is not a lack of interest by physicians and scientist, but rather a lack of interest in financial support.
—ThyroidCancerHelp, December, 2007
Thyroid cancer spread to bone (treatment of)
In treating bone metastases, there are certain aspects that must be understood.
First, radioactive iodine is infamously ineffective in dealing with most bone metastases, particularly if they are macroscopic (able to be seen on radiology studies, rather than just as areas of uptake on an I-131 nuclear scan).
Second, they are relatively resistant to external beam radiotherapy. It is extraordinarily rare for the tumor at a bony site to be killed completely by mere external beam radiation. Enough survives to reconstitute and expand the tumor in due course.
Third, bones serve the vital role of support. Cancer metastases eat their way through the bone where they reside, compromising its structural integrity. The result is fractures, spinal compression with spinal cord damage, etc. Any treatment that kills or removes tumor from a bone must also restore the structural support of that bone.
For these reasons, my clinical experience is that proper treatment of most metastases to bone is best done by having the tumor surgically excised and appropriate titanium, cement, etc. used to support the site. Then the operated site is treated with systemic radioactive iodine (if the tumor is still capable of taking it up) or external beam radiotherapy (if the tumor is no longer responsive to radioactive iodine).
The best role for stereotactic radiosurgery is for sites that are not accessible to the surgeon without great risk to the patient (such as deep within the brain).
—ThyroidCancerHelp, August, 2007
Thyroid cancer tumors (microscopic) and radioiodine scans
When radioactive iodine scans, either performed with a tracer dose of radioiodine (diagnostic scans) or after a treatment dose of radioiodine (post-therapy scans), show areas of tumor uptake it may be evaluated using an ultrasound (for the neck) or a CT scan without contrast (for the chest) or an MRI scan (for other body parts). These studies (ultrasound, CT scan, MRI scan) are termed "anatomical studies". Tumor sites that are visible with the radioiodine scans but are not visible with anatomical studies are considered to be "microscopic" disease sites. Such sites are usually very responsive to the radioiodine therapy.
Sometimes the stimulated (by hypothyroidism or Thyrogen) thyroglobulin level is elevated during a radioiodine scan, even though the scan may not show any tumor sites. In some of these cases, giving the person a radioactive iodine treatment dose (usually 150 to 200 mCi) will eliminate or substantially reduce the stimulated thyroglobulin level when it is assessed later, after at least 4 months. In this situation, it is likely that the radioiodine was taken up into the microscopic lumps of thyroid cancer cells and killed them, even though they were far too small to reveal themselves on the radioiodine scan.
—ThyroidCancerHelp, July, 2007
Thyroid cancers and genetic mutations
Approximately 25-30% of people who are found to have medullary thyroid cancer are found to have inherited mutations in a specific gene (the RET proto-oncogene) that is the underlying cause of their medullary thyroid cancer. Clinical experience has shown that differences in the site of that gene that the mutation is found seem to be associated with some differences in the behavior of their cancer. Also, the mutation within a family group of medullary thyroid cancer patients is usually the same mutation site. For that reason, seasoned medullary thyroid cancer veterans often use their specific mutation as a type of identifier to other similar veterans.
Papillary and follicular thyroid cancer patients do not have such clear-cut genetics, although it is very certain that a minority of them do have some type of familial inheritance. There is active research in a number of laboratories on the genetics of these cancers, but it is a distinctly different situation from inherited medullary thyroid cancers and still only vaguely understood.
—ThyroidCancerHelp, August, 2007
Thyroid cancers differ from other head and neck cancers
"Head and Neck Cancers" is a general term that applies to a wide variety of tumors of this region, from squamous cell carcinomas to salivary adenocarcinomas. It is sometimes used to include thyroid cancers. Thyroid carcinomas are very different from nearly all other types of head and neck cancers in a wide variety of ways.
[topic continued from a different post]
If differentiated, they are the only cancers that express the combination of tissue specific genes that make radioactive iodine scanning and therapy possible. Thyroid cells and most cancers coming from thyroid cells are the only cells in the body that make thyroglobulin, permitting this to be a unique tumor marker after thyroidectomy.
There are unique biological properties of different tissues and tumors that define response to chemotherapies. That's why the drugs used to treat breast cancers differ from those used for colon cancer. Thyroid cancers, to date, haven't any cytotoxic chemotherapy that is clearly useful or effective under most circumstances. This is why the drugs used to treat other head and neck cancers are not appropriate for thyroid cancer. In addition, the distinct patterns of tumor spreading through the body and bloodstream are unique to different types of thyroid cancer and often are different from other types of head and neck cancers.
If you want further explanation, on a cell biology or molecular level, it will require appropriate funding and time for my laboratory (and many others throughout the world) to arrive at the specific answers for you. I can provide the address for donations, if requested.
—ThyroidCancerHelp, October, 2007
Thyroid cancers, invasive
The behavior of the thyroid cancer in the thyroid gland suggests how it may behave in the future. For that reason, the invasion of the tumor cells throughout the thyroid gland capsule and into surrounding tissue (fat, muscle, etc.) suggests a more aggressive pattern
of behavior.
The dosing of radioactive iodine varies widely from physician to physician, sometimes without much rational reason. Although I would provide a minimum of 150 mCi I-131 for locally metastatic and invasive tumor (regardless of the "uptake percentage" in the neck), it is not uncommon to get lower doses that have a chance to work well also.
—ThyroidCancerHelp, September, 2007
Thyroid cancer tumors and ethanol use
[There is a] case report of a single effort to deal with a metastasis to the sternum with ethanol injections (Nakada K, Kasai K, Watanabe Y, Katoh C, Kanegae K, Tsukamoto E, Itoh K, Tamaki N 1996 Treatment of radioiodine-negative bone metastasis from papillary thyroid carcinoma with percutaneous ethanol injection therapy. Ann Nucl Med 10:441-444). As a case study, it does not provide much information regarding this application of that technique. In fact, with bone metastases from other cancers, ethanol injections do not have much advantage in diminishing disease progression; rather they are used to temporarily relieve pain from the metastases in hospice patients. Another technique that can be somewhat more effective is radiofrequency ablation (RFA). Both ethanol injections and RFA are generally inferior to surgical management of a metastases to bone since only the surgery permits the opportunity to strengthen the resected bone using appropriate hardware. Any ablative procedure (ethanol, RFA, surgery) is best followed by external beam radiotherapy to the affected site.
Bone metastases, particularly when there is no uptake of radioactive iodine, are notoriously recalcitrant to non-surgical techniques and medications. For soft tissue iodine non-avid metastases (lung, liver, etc.) there have been some significant advances in care. Although not yet registered as an FDA-approved indication, sorafenib and other related tyrosine-kinase inhibitors have been useful in retarding progression of tumor and enhancing the quality of life (although there is not yet sufficient data regarding effects on longevity). Likewise, my results with thalidomide (published) and lenalidomide (on-going clinical trial) have also demonstrated the value of these approaches. More research is necessary and likely to be quite fruitful.
—ThyroidCancerHelp, March, 2008
Thyroidectomy, healing after
The surgical wound after a thyroidectomy and neck dissection is a wound much like any other. Hopefully, it has been carefully prepared and kept sterile to avoid infection. It is always expected to form some scar tissue, both internal (between muscle layers in the neck) and external (the visible scar, hopefully minimal). Imagine that you've been dueling with bandits as the star of an Indiana Jones movie and sustained a scimitar slash to your neck. You'd fully expect some post-operative wound discomfort, a number of weeks of tenderness, stiffness lasting a bit longer, and perhaps some unusual sensations when moving your neck or swallowing for some time to come. Like any such wound, either by scimitar or by scalpel, as time goes on and you employ appropriate stretching exercises, to enhance mobility and reduce internal adhesions, you'd expect to gradually feel much improved and ultimately to feel "normal" (whatever that is).
—ThyroidCancerHelp, February, 2008
Thyroid hormone and travel
When my patients go hiking in the mountains, visit the pyramids, go on their African camera safaris, or bask in the hot tropical sun of Tahiti, the first thing that I do is to ask them to take me and Sara along.
Unfortunately, instead they ask about keeping their levothyroxine tablets potent despite the heat. I provide the following advice: 1) Only take the tablets that are needed for the trip, plus several extras; 2) There are inexpensive wide-mouthed thermos bottles used to carry small portions of soup. These are excellent places to keep levothyroxine tablets. Should the environment be particularly hot (such as exploring an active volcano), an ice pack or cold pack can be inserted with the pills into the thermos. 3) Always keep the pills in hand-carried luggage when flying, but best NOT in your pocket (your thighs are much too warm).
—ThyroidCancerHelp, July, 2007
Thyroid hormone, obesity and tiredness
There is an epidemic of obesity. Particularly as we age, it seems that dietary habits that were keeping us trim when younger, now cause huge amounts of flab to accumulate. There are far greater numbers of obese individuals than numbers of hypothyroid individuals who are not taking sufficient thyroid hormone.
It is VERY EASY to know if you are receiving sufficient thyroid hormone. As long as you have a healthy pituitary gland, the TSH level reveals your own body's response to your thyroid hormone level. A TSH in the normal range (the target for hypothyroid patients who do not have thyroid cancer; this range is currently being narrowed to 0.5 – 2.5), despite the presence of obesity, verifies that the thyroid hormone level is NOT contributing to the weight gain. For thyroid cancer patients taking proper amounts of thyroid hormone, particularly if they have appropriately suppressed the TSH to levels under the "normal range", the thyroid hormone level is certainly not contributing to their weight gain.
The causes of obesity are multifactorial and many of these causes are still being uncovered. Certainly, our social changes in recent years have been a major contributer to this problem. For many of my patients with morbid obesity (more than 100 pounds above their proper weight), the health risks from their obesity greatly exceed the health risks of their thyroid cancer. I refer more patients to Weight Watchers than to any other consulting service.
Tiredness is a similar issue. Many people are tired despite normal thyroid hormone levels. I'm often quite tired when typing these responses at 2 AM. There are a large number of people whose tiredness has evaded diagnostic attribution and are labeled as "chronic fatigue syndrome" and sometimes "fibromyalgia". Recently, it has become apparent that a large number of such people have sleep apnea as the cause of their tiredness. Since obesity will worsen sleep apnea, the combination of such problems places this possibility as even more probable. The ONLY way to diagnose sleep apnea is with a properly performed study in a sleep lab.
Of course, there are a number of individuals whose tiredness and obesity defy our explanations. Sometimes a process of careful dieting and exercise training can help.
—ThyroidCancerHelp, March, 2008
Thyroid hormones are degraded by heat
As stated earlier, nobody should be taking any type of chronic thyroid hormone therapy other than a name-brand pure levothyroxine preparation. These preparations (and all thyroid hormone preparations) are very sensitive to heat. The temperature degrades the hormonal content of the tablets and "coating" them in anything doesn't improve things at all.
A few years ago I had followed the news of allegations against a major pharmacy chain regarding the transportation conditions of its pharmaceuticals. A former employee stated that trucks carrying drugs were not temperature-controlled and were subjected to temperatures exceeding 110 degrees (F) for several days at a time, yet these medications were placed on shelves of their drugstores and used to fill prescriptions. Sadly, this does not seem too surprising, although it is severely disappointing. It might also explain why some patients note elevated TSH values despite excellent compliance with taking their levothyroxine preparation.
Levothyroxine preparations of any brand are exquisitely heat-sensitive and will rapidly lose hormone activity if exposed to temperatures high enough to soften a milk chocolate bar. Even if stored under perfect temperatures, these tablets lose 5% of their potency every year. Under adverse storage conditions, it is likely that minor differences in hormone content due to different brands of levothyroxine would be dwarfed by the changes induced by tablet degradation.
At this time, I know of no systematic effort to police the storage conditions of pharmaceuticals carried by both wholesalers and retail distributors. In addition, many people obtain their medication through the mail with entire pill packages exposed to high temperatures in outdoor mailboxes sitting in the sun. Often, I suggest that the cost savings of such mailings are far less important than the confidence in the potency of the medications purchased from the local drugstore. On the other hand, recent news can even shake our confidence in the local store.
—ThyroidCancerHelp, July, 2007
Thyroid lab tests (time of drawing blood)
The best time to draw a blood sample is either in the morning, prior to taking your levothyroxine dosage, or more than 9 hours after taking the levothyroxine dosage. The reason for that is contained in a report of one of my research studies:
Ain, K. B., F. Pucino, et al. (1993). "Thyroid hormone levels affected by time of blood sampling in thyroxine-treated patients." Thyroid 3(2): 81-5.
—ThyroidCancerHelp, October, 2007
Thyroid (lifetime with no), effects of
There is absolutely no ill consequence for loss of a thyroid gland, provided that levothyroxine, in sufficient quantities, is taken. This has been known for a long time. Although there are a few additional hormones made by the thyroid gland besides thyroid hormone, notably calcitonin, it is now very clear that the absence of calcitonin has not caused any physiological or clinical problems. The short answer is, yes, levothyroxine therapy replaces everything of consequence when the thyroid is removed.
—ThyroidCancerHelp, September, 2007
Thyroid mass: verify the pathology for unusual thyroid masses and dosing Levothyroxine
[Editor’s Note: this posting dealt with confusion over a thyroid mass].
First, although benign goiters can be asymmetrical, it is distinctly unusual for one side of a thyroid to be 12 times normal size and the other side to be normal in size unless the enlarged lobe contains a malignancy. Strangely enough, the larger a thyroid tumor is, often the more difficult for the pathologist to completely examine the tumor sufficiently to determine if it is a cancer. For that reason, anyone with such a large and asymmetric thyroid mass should have the slides and tissue blocks from their thyroid surgery reviewed by another pathologist who is particularly famous for their expertise in thyroid cancer.
If the only thyroid cancer that is definitively present is: a single focus of papillary thyroid cancer, smaller than 10 mm in diameter, completely contained within the gland, not associated with any enlarged lymph nodes or tumor spread anywhere else in the body, and not an aggressive variant (such as tall cell variant), then there is NO NEED for suppressive thyroid hormone therapy or any other specific thyroid cancer treatment.
The second issue is concerning thyroxin (levothyroxine) therapy. The particular dosage of thyroid hormone that is needed to keep the TSH in the normal range (for a hypothyroid replacement therapy) can vary considerably from person to person. Although the average dosage is 1.6 MICROgrams per kilogram body weight, in any particular person the dosage can be quite different. The KEY POINT is that (as long as the pituitary and hypothalamus portions of the brain are normal) the daily dosage of levothyroxine that results in a normal TSH after at least 6 weeks of consistent pill-taking is the right one for that person.
—ThyroidCancerHelp, August, 2007
Thyroid nodules evaluation
There are two major criteria for performing thyroid surgery: if there is a significant suspicion or documentation of malignancy or if the thyroid (usually as a goiter) is sufficiently enlarged to push on vital structures in the neck (the windpipe, esophagus, arteries, veins, etc) or block the thoracic outlet (the region connecting the neck and the chest).
When evaluating a thyroid nodule (usually over 1 cm in diameter) the only fine needle biopsy result that does not usually require surgery is the demonstration of unequivocally benign thyroid cells in the biopsy sample. Merely the "absence of cancer" without showing normal thyroid cells is insufficient. On the other hand, although it is clear that the demonstration of cancer in the biopsy warrants surgery, any results from the biopsy that are listed as "suspicious" or "indeterminant" also warrant thyroid surgery. The difference is that a clear demonstration of cancer tells the surgeon to do a total thyroidectomy from the very beginning, whereas an "indeterminant" biopsy result often results in a complete removal of the side of the thyroid gland that contains the nodule, with further complete removal of the gland if the pathology results show cancer or if more suspicious findings are seen by the surgeon.
In an example in which a 3 cm nodule is pressing on the esophagus, it is already necessary to perform thyroid surgery. The biopsy before the surgery would tell the surgeon whether he should do a total thyroid removal or just half of the thyroid removal (pending the evaluation by the pathologist).
—ThyroidCancerHelp, July, 2007
Thyroid nodules less than 10 mm
All of us are acutely reminded of our mortality when a loved one falls gravely ill and we are made severely nervous by anything suggesting a similar issue in ourselves. Fortunately, the reality is that the majority of human beings on this planet are likely to have a 3 mm thyroid nodule when explored by sensitive ultrasound. Such a nodule is too small to biopsy and too small to worry about in any practical way. The only reasonable approach is to repeat the ultrasound in a year and perform a fine needle biopsy if the nodule exceeds 10 mm (1.0 cm) in diameter. Despite any emotional misgivings regarding a tiny 3 mm nodule, to do anything more is unwarranted and not advised.
—ThyroidCancerHelp, September, 2007
Thyroid surgeon (important to research your)
It would not be appropriate for me to list specific names of thyroid surgeons in this venue; however this is a very important issue to briefly discuss.
First, remember that "bricks don't treat patients, physicians do." Thus, don't look for a specific hospital, but rather look for a specific surgeon. There are highly esteemed major medical centers that you may go to and find an inexperienced surgeon doing your surgery. Likewise, there are small community hospitals that may have a particular fantastic thyroid surgeon on staff.
Second, make use of contacts among your physicians. A thyroid cancer patient will need to have an endocrinologist with some experience in thyroid cancer to take care of them after surgery. Consulting such a physician before the surgery enables a person to ask this physician about their own opinions regarding the appropriate surgeon to consult.
Lastly, interview your surgeon (respectfully, not as an interrogation). Ask how many total thyroidectomies he/she has performed per year (should be at least 25). Ask how many patients had complications of hypoparathyroidism (low calcium problems) or vocal cord paralysis and if these rates were affected by having a large number of patients with very large and aggressive tumors. Ask what kind of surgery is planned (anyone with a biopsy proven cancer should have nothing less that a TOTAL thyroid removal). The minimal surgery should be total removal of half of the thyroid (only if the biopsy had not been definitive as cancer) and NEVER use any surgeon who proposes to only remove the tumor nodule (a "nodulectomy").
Learn enough about your surgeon to have confidence in their care.
—ThyroidCancerHelp, August, 2007
Thyroid tumor capsule invasion vs thyroid capsule invasion
When pathologists talk about thyroid tumors in the thyroid gland, there are two different "capsules" that are mentioned. One is the "capsule" of the tumor itself (many thyroid cancers do not have a fibrous covering or "capsule"). The other "capsule" is the thin fibrous covering of the thyroid gland itself.
For follicular and Hurthle cell thyroid cancers, it is important for the pathologist to see if the tumor invades the "tumor capsule" since this is one of the features that show that it is a cancer rather than a benign growth (called an adenoma). In addition, another sign of this tumor being a cancer is if it shows any evidence of "eating its way" into a blood vessel (vein or artery), called "vascular invasion."
For all types of thyroid cancer, evidence that the primary tumor (in the thyroid gland) has "eaten its way" through the thyroid gland capsule is termed "extrathyroidal invasion" and is evidence that the tumor is particularly aggressive. Even more aggressive is a thyroid cancer that has invaded through the thyroid capsule and "eaten its way" into nerves, muscles, windpipe, esophagus, or other structures in the neck.
—ThyroidCancerHelp, August, 2007
Thyrotoxicosis (too much thyroid hormone), dealing with
For most patients with thyroid cancer (except medullary thyroid cancer) it is desirable to keep the TSH suppressed to 0.1 or less. This is often achieved with careful adjustment of the levothyroxine dosage and good compliance with taking this medication; however, some people will have mild symptoms of thyrotoxicosis on this dosage. For those people, with resting pulses over 80, nervousness, palpitations, trouble getting to sleep, panic attacks, etc., the addition of a simple once-per-day cardio-selective (beta-one selective) beta-blocker will eliminate these symptoms and provide a perfect balance to the levothyroxine therapy. Commonly used beta blockers include: atenolol or extended-release metoprolol.
—ThyroidCancerHelp, February, 2008
Treatment delays (necessary vs. unnecessary)
It's unfortunate that there is an unspoken prejudice by many surgeons that thyroid cancer is such an "easy cancer" to treat that the treatment of a thyroid cancer patient is dealt with as a low priority issue. Sometimes there are legitimate reasons to delay thyroid cancer surgery, such as: a pregnant patient in their third trimester, a person with severe heart disease who may need cardiac surgery before thyroid surgery, etc. Sadly, I find it unlikely that a surgeon would accept a delay in surgery for their own family member with bulky and locally metastatic thyroid cancer. In that context, it seems very difficult to believe that a surgical group would have so many critical and non-elective surgical cases so as to delay such a patient for six weeks. It may be very useful, in such a situation, to discuss these concerns directly with the surgeon (not their nursing or clerical staff) to determine if they have an attitude problem or 6-weeks worth of emergency surgery cases.
It is also very intelligent and wise to wish to optimize post-operative radioactive iodine treatment. If, in fact, the surgeon is capable and able to surgically remove the entire thyroid gland, all gross tumor, as well as perform a sufficient neck dissection to eliminate all palpable metastatic lymph nodes, there is no reason why radioactive iodine therapy and subsequent scanning could not be delayed until interfering stable (non-radioactive) iodine (from the CT contrast dye) has been cleared from the body. The procedure to determine this, a 24-hour urine iodine collected at the end of a one-week low iodine diet, is simple enough to do and is likely both cost effective and comforting, when it verifies clearance of the stable iodine.
Be informed. Be even-tempered and reasonable. Be firm and forthright. It is unlikely that the physician's office nurses and secretaries have sufficient grasp of the particular issues, so it is important to deal with the physicians directly.
—ThyroidCancerHelp, September, 2007
Treatment (practical sequence of)
The approach to thyroid cancer must be very practical to be effective. First, the practical use of the available tools requires them to be used in the most optimal way. If disease persists despite these efforts, then the approach is altered accordingly. Radioactive iodine is the only currently known systemic (involving the entire body) treatment that has reasonable chances to kill thyroid cancer cells. It is most effective in tiny deposits of tumor and least effective in large deposits. For that reason, large deposits are best dealt with surgery followed later by radioactive iodine treatment.
The exact "percentage" of treatment successes with radioactive iodine is not easily gleaned from the published literature, with varied approaches and varied reliability, but would not be a useful number, even if it could be determined. This is because the practical management of thyroid cancer requires one to use this approach and either show its success or move on to another method if it is not successful. In the case of demonstrated radioiodine uptake on scans with no macroscopic tumor evident and an appropriately modest elevation of thyroglobulin, the majority of cases are successfully managed with further radioactive iodine given appropriately.
It is certainly possible that the uptake in the neck is only a portion of the residual disease (lurking elsewhere) and the radioactive iodine treatment will not prove completely successful. That situation will only be uncovered by pursuing the I-131 treatment and then demonstrating persistent thyroglobulin elevations despite resolution of the neck uptake.
In regards to thyroid cancer tumor dissemination, this disease easily travels through the lymphatic vessels and blood vessels. In many thyroid cancer patients, careful analysis of circulating blood (using reverse transcriptase-polymerase chain reaction assessment for thyroglobulin messenger ribonucleic acid; an experimental method) reveals that thyroid cancer cells travel freely throughout the body. It is never surprising to see this tumor pop up in lymph nodes or in nearly any site in the body. That is the reason for life-long follow-up by a skilled physician.
—ThyroidCancerHelp, October, 2007
TSH (effects of thyroid hormone doses to suppress)
For most people taking properly adjusted doses of levothyroxine, so that the TSH is under 0.1 using the lowest possible branded levothyroxine dosage, there is no long term ill consequence. For some people on such a regimen, their heart rate is a bit higher than desirable (more than mid 80's while at rest). For those people, there is a risk (over a long period of time) for the left side of the heart to become a bit thicker (left ventricular hypertrophy) which is not desirable. If such people are placed an a beta-one-selective beta blocker (such as metoprolol, atenolol, etc.), then the pulse rate is lowered, the heart changes are prevented, if blood pressure is a problem then it's helped, if migraines are a problem then they're helped, if panic attacks are a problem then they're helped, and etc.
A few people are unable to tolerate beta-blockers due to allergies, an extremely rare reaction with hair loss, or severe asthma. For such people, it is important to balance out the need for such suppression (the aggressiveness of the features of the thyroid cancer) with the side effects of the thyroid hormone suppression (despite maximal optimization of the dose and attempts with mitigating agents, such as calcium-channel blockers, etc.).
Modern analyses do not support any significant additional contribution of thyroid hormone suppression of TSH towards osteoporosis.
—ThyroidCancerHelp, September, 2007
TSH elevation and LOW IODINE DIET are INDEPENDENT from each other
Two very basic criteria, for preparing thyroid cancer cells to be able to efficiently take up radioactive iodine in order to be scanned or treated, are: elevated TSH (above 30 mIU/L) and depletion of non-radioactive (stable) iodine. These are important for very different reasons and are totally independent from each other.
Elevation of TSH is necessary to stimulate any residual thyroid cancer cells, via their TSH-receptors on their cell membranes, to "wake up", start manufacturing iodine pumps (NIS; the sodium-iodide symporter), and to start producing thyroglobulin. Without sufficient TSH to stimulate thyroid cancer cells, they will not be able to produce sufficient NIS to "suck up" radioactive iodine that has been swallowed and absorbed into the blood.
The Low Iodine Diet (www.lidcookbook.com) is needed to reduce the stable iodine from the diet sufficiently so that the radioactive iodine has an opportunity to enter the thyroid cancer cell. One simplistic way to think of this is to imagine the thyroid cancer cell as a sponge and the radioactive iodine as a liquid that you want to absorb into the sponge. If the sponge is soaking wet (with stable iodine), it will not be able to absorb the liquid. In order to absorb the liquid, you need to "wring the sponge dry" (go on a low iodine diet).
No matter how high the TSH is, the low iodine diet is completely necessary. No matter how well the low iodine diet is followed, insufficient TSH elevation will prevent the thyroid cancer cell from taking in the radioactive iodine. Both preparations are necessary and doing just one of them is insufficient.
—ThyroidCancerHelp, July, 2007
TSH levels for radioiodine scans and therapy
The minimal level of TSH for radioactive iodine scanning or therapy was established by evaluating the effects of different TSH levels during hypothyroid preparations and determining what the "minimal" TSH would be to produce reasonable radioiodine uptake. It was published as: [Goldman JM, Line BR, Aamodt RL, Robbins J 1980 Influence of triiodothyronine withdrawal time on 131I uptake postthyroidectomy for thyroid cancer. J Clin Endocrinol Metab 50:734-739].
Clearly, higher TSH levels for longer periods of time produce greater stimulation of iodine uptake and thyroglobulin production. I observe this in my patients undergoing dosimetry evaluations for use of high-dose radioiodine therapy. For example, when starting dosimetry one person's TSH was 79.0 and their thyroglobulin was 267.0. One week later, just before therapy, their TSH was 110.0 and the thyroglobulin was 341.0. The selection of a TSH of 30 is a compromise between what is practical/tolerable for patient preparation and what is acceptable for treatment or scans.
Again, using Thyrogen is another clinical compromise in which the comfort and convenience of its use is weighed against the relative decrease in iodine uptake and thyroglobulin production in comparison to a hypothyroid withdrawal preparation. In many patients, with low-risk tumors and previous clear scans and undetectable thyroglobulin levels using hypothyroid preparation, Thyrogen is a perfectly reasonable and appropriate choice. For other patients without such features, Thyrogen may not be as good a choice.
I have some patients with unusual situations that require the use of Thyrogen: psychologically unstable with risk of suicidal depression, defective pituitary glands that cannot make TSH, too debilitated to tolerate hypothyroidism, lack of financial/insurance coverage to afford Thyrogen, etc. There are some patients, given the choice between Thyrogen and hypothyroid preparation prefer the greater certainty of being hypothyroid, despite the inconvenience. My thyroid oncology practice utilizes both techniques in roughly equal numbers amidst a very large number of patients.
When using Thyrogen, since the typical regimen is to inject Thyrogen on Days 1 and 2, administer the scan dose on Day 3, scan on Days 4 and 5, and draw the thyroglobulin level on Day 5, any TSH levels obtained on Day 5 are often lower than 30.0 because of the pharmacokinetics of Thyrogen. We can't use the same criteria of TSH levels for Thyrogen injections as we do for hypothyroid withdrawal.
—ThyroidCancerHelp, August, 2007
TSH (frequency of checking the)
The frequency of assessing the TSH level is based upon the half-life of levothyroxine (a week: it takes 6-8 half-lives, that is 6-8 weeks, before any dose change will produce a new "steady-state" thyroid hormone level and TSH level. It is also based upon the "clinical history" of the particular patient. If a person has had "rock-steady" TSH levels on the same dosage of carefully taken and maintained levothyroxine for many years, the frequency of testing can be as little as once yearly. On the other hand, erratic TSH levels due to a variety of causes (compliance, storage conditions of medications, inappropriate generic substitution, forgetfulness, interfering substances like iron supplements, etc., etc.) can compel more frequent testing. For patients who are pregnant and on levothyroxine, we advise testing every month of the pregnancy. The answer is not simple and pat. It is individualized for the situation and the person.
—ThyroidCancerHelp, September, 2007
TSH suppressed, purpose of
In current medical practice, the usual reason to suppress the TSH (to 0.1 or less) is for the management of thyroid cancer (except medullary thyroid cancer). In rare circumstances, people with enlarged benign thyroid glands (benign goiters) may be given sufficient thyroid hormone to suppress the TSH in an effort to "shrink" the goiter. This is often unsuccessful. For the past twenty years, it has been clearly known that suppression of TSH is NOT an appropriate way to deal with thyroid nodules. These are the only reasons that I can think of a reason to give more than the proper dose of levothyroxine that results in a normal TSH.
For thyroid cancer patients who need to maintain a suppressed TSH, it is important that the physician carefully titrate the levothyroxine dosage to the lowest dosage that will effectively suppress the TSH. This averages to around 2.0 mcg/kg body weight/day; however, there is a wide range of variation between different person's suppression dosage. For most people, such a dosage does not cause any appreciable symptoms; however, for some people it causes the heart rate to be too rapid (more than 80 beats per minute at rest) or contributes to insomnia or nervousness. In such circumstances, the addition of a cardio-selective beta blocker (usually metoprolol or atenolol) will usually balance out this treatment and prevent such side effects.
—ThyroidCancerHelp, December, 2007
TSH suppression, controversy regarding
There is no clear agreement on the optimal level of TSH suppression appropriate for thyroid cancer patients. On one side, it is clear that TSH is a growth factor that promotes the growth of thyroid cancer cells. There are reasonable studies showing that the risk of thyroid cancer recurrence increases as the TSH increases. For aggressively invasive or distantly metastatic cancers, TSH should be kept less than 0.1 at all times. For other, less aggressive thyroid cancers, the debate continues.
On the other side, it is clear that those patients who maintain a TSH <0.1 and have a persistent rapid heart beat (greater than 80 beats per minute while at rest) are at risk for having a thickening of the left side of their heart and are also at risk for having rapid abnormal heart rhythms. These problems can be prevented, while maintaining the TSH suppression, using proper doses of beta blocking medications; however, there are a small number of patients who can't take such medications. In that case, the benefit has to be weighed against the risk. In addition, there is an enhanced risk of osteoporosis, particularly for post-menopausal women (who are not on estrogen).
The unresolved controversy is in regards to patients with less aggressive tumors, as to how low to keep the TSH. It's my practice to keep the TSH suppressed to <0.1 in all of my patients with non-medullary thyroid cancers who are able to safely tolerate it (sometimes with the help of beta blockers) without evident adverse effects. This is partly based upon our observations on how TSH affects the growth of human thyroid cancer cells in the laboratory and our inability to define any higher level of TSH that will not result in stimulating the growth of any residual thyroid cancer cells.
—ThyroidCancerHelp, August, 2007
TSH (target) for thyroid cancer patients
For patients with clinically significant thyroid cancer (except for medullary thyroid cancer) the target TSH is less than 0.1. If this can be achieved while keeping the FREE T4 level within the normal range, then this is excellent. There would be no reason to alter such a situation as long as it is not causing any adverse symptoms.
—ThyroidCancerHelp, March, 2008
TSH thyroid hormone suppression, dealing with symptoms
When it is appropriate to suppress the TSH with levothyroxine in the context of thyroid cancer treatment, we aim for the lowest daily dose of levothyroxine that will do the job. Most of the time, this will not cause thyrotoxic symptoms, but such symptoms can occur. If and when they do, an appropriate approach is to start the patient on a beta blocker. There's a nice section about these drugs in "The Complete Thyroid Book." I typically utilize a long-acting beta-1 selective drug, such as atenolol or metoprolol LA. A sufficient dosage of daily beta blocker will provide the appropriate balance and block most of the thyrotoxic symptoms.
—ThyroidCancerHelp, October, 2007
Tumor dedifferentiation, issues and questions
The appearance of thyroid cancers under the microscope is helpful to "suggest" the differentiation status of the tumor, but it is not definitive for predicting the "functional differentiation" of the tumor. Simply put, the tumor may not look too bad, but it still may not work well to take up radioactive iodine and respond to that therapy.
Additionally, all of the thyroid cancer cells in a thyroid cancer tumor are not the same. They are heterogeneous, that is, they all vary in ability to take up iodine, growth rate, tendency to spread, and aggressiveness. If very aggressive cells are present in sufficient quantity, even though the more responsive cells can be effectively eliminated with well-administered radioactive iodine therapy, with time these less differentiated cells proliferate and constitute the recurrent tumors.
Sometimes tumor cells "dedifferentiate" over time, if previous treatments have not been given in an effective fashion. More often, the tumor contained sufficient "dedifferentiated" cells at the time it was discovered and first treated with surgery, that had already spread from the thyroid (either via the lymphatic vessels or via blood vessels). In that case, the die was already cast that the tumor would not fully respond to radioactive iodine treatment.
When non-iodine avid tumors recur in the neck, it is usually good practice to treat them with surgery and follow this with EXTERNAL BEAM RADIOTHERAPY INSTEAD OF RADIOACTIVE IODINE.
Such description is not difficult to provide to this group. On the other hand, if you truly want to know WHY it happens, then you are asking for an answer to questions that I and my laboratory staff have spent two decades exploring. We have some answers, but certainly not sufficient answers, yet. For those interested to read some of our scientific publications and those of our colleagues, search the PubMed database at the National Library of Medicine.
—ThyroidCancerHelp, July, 2007
Tumor in the neck, correct approach to residual
Persistent thyroid cancer, made evident by elevated thyroglobulin levels and localized to the neck by evidence of radioactive iodine uptake on scanning, needs to be treated after appropriate evaluation. The first need is to verify the absence of macroscopic tumor requiring surgical removal. This can be done with ultrasound or MRI (as it was done in this case). In the absence of macroscopic tumor, the radioactive iodine uptake that defined the tumor location on the scan also defines its likely successful treatment with radioactive iodine.
There is no "percentage uptake" that indicates whether such tumor is treatable with radioactive iodine (to suggest this suggests ignorance of the physicians). This is because the key missing element is the physical size (in grams) of the tumor (because it is too small to visualize). For example, if there were one gram of tumor with only 1.0% uptake, this would define a tumor with the identical uptake of normal thyroid tissue, about 100 times the uptake of typical treatable thyroid cancer. If the uptake were 0.1%, but the tumor was 0.1 gram, it would denote the SAME uptake. Clearly, in the absence of tumor large enough to measure (or weigh), no one can define ANY percentage of uptake as being too little for therapy. That is why typical I-131 treatment doses of 150 to 200 mCi are usually very effective in such circumstances, provided that preparation (HYPOTHYROID prep and low iodine diet) is optimal. Dosimetry is NOT appropriate for such circumstances.
PET scans are not appropriate for circumstances in which there are only modest elevations of thyroglobulin and there are clearly defined sites of radioactive iodine uptake delineating differentiated tumor. Anything showing up on a PET scan is typically unable to concentrate radioiodine since only such tumors have sufficient glucose uptake for imaging. PET scans are most useful when the thyroglobulin is elevated and there are NO sites of radioactive iodine uptake.
The most appropriate approach for patients with pathologic radioactive iodine uptake in the neck (of ANY percentage), absent macroscopic tumor by ultrasound or MRI, and minimal thyroglobulin elevations that are appropriate for the sites of uptake seen, is to get radioactive iodine therapy.
—ThyroidCancerHelp, October, 2007
Tumors (aggressive) that do not suck up iodine
When macroscopic thyroid cancer is clearly documented to have spread to distant sites, such as the lung, and is also clearly documented to NOT take up radioiodine by a properly prepared I-131 whole body scan (making sure that CT contrast and other interfering iodine agents were not involved), then there is NO reason to proceed with further radioactive iodine therapy. This is particularly evident if the tumor sites are clearly evident on a PET scan since tumors that take up FDG the most, generally take up I-131 the least.
When I take care of patients with disseminated thyroid cancer that does not take up iodine and is not completely able to be removed by surgery, it's important to focus on taking care of disease in different parts of the body differently. For tumor in the neck, surgery is very important and this is generally followed up with external beam radiotherapy (XRT) to the neck and superior mediastinum. It is necessary to carefully evaluate the entire body, particularly the spine and brain, to make sure that tumors are not growing in these critical sites. If found at such sites, we generally employ surgery followed by XRT to that site (in the brain we sometimes use focused beam XRT, such as gamma knife). For tumors at structurally critical sites, such as in the hip joint, our orthopedic surgeon's skills and experience have been very useful. For tumor sites in inoperable locations, such as tumor spread through the lungs, we maintain careful suppression of the TSH (under 0.1) and monitor these sites for progression. Should there be evidence of reasonably rapid progression, despite the preceding efforts, we offer the patient the opportunity to enroll in a phase 2 clinical trial utilizing particular new medications. For example, my own clinical trial with lenalidomide has proven particularly successful in nearly 70% of our patients to date. These trials can be found listed on the PDQ database accessed through the National Cancer Institutes' website. It is the appropriate role of your physician to contact the Principle Investigator of those trials that seem appropriate to see if the patient meets the criteria for enrollment and to see if the experimental agent has shown any usefulness.
—ThyroidCancerHelp, January, 2008
Tumors, approach to locally invasive aggressive
When thyroid cancers grow in an aggressive fashion, demonstrating this by invading into vital structures in the neck (muscles, cartilage, trachea, esophagus, etc.), they need equally aggressive therapy. This type of primary tumor presentation is statistically associated with current or future distant spread of disease (to lung, bone, etc.) about 50% of the time. There is an equally high rate of local recurrence.
Because of this, it is my practice to perform radioactive iodine dosimetry on such patients in order to be prepared to provide maximal safe dose therapy (up to 800 mCi per dose in some patients). Unfortunately, only a handful of hospitals are skilled in performing this dosimetry in the United States and no such places are known by me to exist in Canada (or possibly in Europe). For those physicians unable to obtain reliable dosimetry studies, empiric doses of 200 to 250 mCi I-131 are often the best that they can do.
It is critical to fully evaluate such patients for extent of disease using radiographic studies (without iodine contrast; using MRI with gadolinium, CT scans without contrast, ultrasounds) as well as other nuclear studies (PET scans). Should there appear to be tumor that does not demonstrate sufficient radioactive iodine uptake (as seen on the post-therapy whole body scan; 2 to 7 days after the I-131 treatment dose) then it is wholly appropriate for external beam radiotherapy (XRT) to be directed to the neck and superior mediastinum.
Should macroscopic tumor be found in distant sites that are localized (bone or limited sites in liver, brain, etc.), these tumor sites should be surgically excised before administration of XRT.
—ThyroidCancerHelp, October, 2007
Tumors, approaches to aggressive
As one of the earliest proponents of considering the histologic subtype and differentiation status of thyroid cancers, it is important to understand that physicians are limited by their therapeutic options. Since the ONLY tumoricidal (tumor-killing) systemic (involving the entire body) therapy that can be effective for this cancer is radioactive iodine, for the most part, the specific classification of the tumor is less important than the optimal use of limited therapies.
For that reason, particularly in tumors with aggressive or poorly differentiated features, it is imperative to be as assertive in preparation (hypothyroid TSH >30, strict low iodine diet, assiduous avoidance of CT contrast dye, etc.) and dosing of radioactive iodine (therapy doses greater than 150 mCi for aggressive tumor, use of dosimetry for maximal safe doses (sometimes as high as 700-900 mCi) for distantly metastatic of invasive tumor) as possible. Gross (macroscopic) tumors should be surgically excised whenever possible. When elevated thyroglobulin or radiographically evident masses demonstrate tumor that does not take up radioactive iodine, then appropriate surgery and external beam therapy should be used for sites in which they are appropriate. When tumor is widely spread and unable to be treated by those means, appropriate referral and evaluation for participation in promising clinical trials becomes necessary.
Further details, particularly specific approaches to specific tumor histologies, is of no particular use in this venue and would warrant a treating physician to contact me directly for discussion.
—ThyroidCancerHelp, September, 2007
Tumors (dedifferentiated) in the neck and increasing thyroglobulin
When aggressive thyroid cancers recur in the neck and mediastinum (the upper middle chest, just under the breastbone) and are no longer able to take up radioactive iodine, it is very important that a surgeon operate and remove all of the tumor that can be seen (macroscopic tumor). Despite this effort, undoubtedly there is still residual microscopic tumor (tumor that cannot be seen by the surgeon or the radiologist) that will later re-grow and perhaps spread. That is why it is usually a good idea to follow the surgery with external beam radiotherapy (XRT) to that region to attempt to eliminate or reduce the residual microscopic disease.
ANY measurable thyroglobulin in this situation indicates residual thyroid cancer and any INCREASE in the thyroglobulin (under identical degrees of TSH suppression) indicates increases in the amount of thyroid cancer that is there. If appropriate therapy (as indicated in the preceding paragraph) has not yet been done, it would be a wake-up call to get it done.
—ThyroidCancerHelp, July, 2007
Tumors, low risk
Single intrathyroidal papillary cancers, less than 1 cm in diameter ("occult" cancers), are sufficiently common that nearly a third of the entire population has them (as shown by autopsy studies); yet the incidence of clinically relevant thyroid cancer is many orders of magnitude less. In that context, it is clear that (except for very rare exceptions) such tumors do not constitute sufficient clinical risk of recurrence or progression to warrant any additional treatment after the surgical resection that identifies them.
The key point is to provide sufficient education and follow-up to such patients (neck self exams and regular checkups) so that those very rare exceptions can be identified and dealt with.
One significant problem is the issue of "over-stating risk assessments" in which thyroid cancers that are "lower-risk" are not treated with radioactive iodine or other appropriate therapies. This can be bad because patients in categories with higher risk than the "occult cancers" are denied appropriate treatment because their physicians let their threshold for providing treatment creep upwards into riskier types of cancers. There is too much disagreement in the field of thyroid cancer. Unfortunately, I do not feel that all sides of the controversy are equally well-informed.
—ThyroidCancerHelp, January, 2008
U
Ultrasounds, the role of
Ultrasonography of the neck is an important and useful modality for following thyroid cancer patients; however it does NOT replace radioiodine scanning for patients whose cancer has not yet demonstrated loss of iodine uptake. Typically, trained ultrasonographers are specialized radiologists. In recent years, some endocrinologists have incorporated ultrasonography in their practice; however, they have widely varied experience and training. The American Thyroid Association does not train nor certify physicians in ultrasonography, although its annual meetings usually feature an optional ultrasonography workshop for its members. Appropriate followup of thyroid cancer makes use of ALL relevant modalities, from nuclear medicine studies through thyroglobulin measurement, and from ultrasounds through CT and MRI scans. Wise people don't put all of their eggs in any one basket.
—ThyroidCancerHelp, November, 2007
Urine iodine studies after CT scans
When we perform a one week low iodine diet, in order to check a urine iodine test to see if previous iodinated contrast had passed, we typically do it while the patient is on their levothyroxine medication. This is so we can make an informed choice of when to start the hypothyroid preparation for I-131 scanning or therapy AFTER the results of the urine test are back.
In the case above, although optimal low iodine status would yield a urine iodine of <40 mcg (or ug)/total specimen, we often will be happy to see the level go to <100 mcg before starting the hypothyroid preparation.
Although a urine iodine amount of 135 mcg is a bit higher than we would prefer, it is not so high as to negate the value of the radioactive iodine study or therapy, particularly considering the morbidity of making a hypothyroid individual wait longer in that state. Life is a matter of balances and options. We take the best choices offered.
—ThyroidCancerHelp, January, 2008
V
Vitamin D for osteoporosis
Treatment of osteoporosis is not a particular area of my own expertise. The medical literature states: Vitamin D is also given as a treatment for osteoporosis. In a French study of 3270 elderly women (mean age 84 years) who lived in care homes and were treated for 3 years with calcium (1200 mg daily) and vitamin D (800 IU daily), the probability of hip and all non-vertebral fractures was significantly reduced by 29% and 24%, respectively, compared with placebo. The findings of two other smaller studies suggest a trend for a reduction in non-vertebral fractures in elderly men and women treated with annual intramuscular injection of vitamin D or a daily supplement of calcium and vitamin D. Conversely, in a Dutch study of 2578 elderly but fairly healthy women with a high calcium intake, daily supplementation with vitamin D 400 IU over 3á5 years had no effect on the risk of hip fracture. Taken together, these data indicate that vitamin D should be used routinely in individuals who live in care homes because of a high prevalence of vitamin D deficiency related to low vitamin D intake, low sunshine exposure, and impaired vitamin D synthesis in the skin. (PD Delmas, The Lancet, 2002).
—ThyroidCancerHelp, October, 2007
Vitamins: prenatal and multi-vitamins (iodine and iron)
There are two issues that are important in regards to prenatal vitamins and to most multivitamins.
First, these vitamins contain iodine. They must not be taken at all during the time that one is on a low iodine diet. Just one of these vitamin pills contains three times the total daily iodine that is desired when on the diet.
Second, most of these vitamins contain iron. For that reason, if taken within 5 hours of the levothyroxine dose, they will cause some of the levothyroxine to fail to be absorbed. The solution is to take prenatal vitamins or other multivitamins at bedtime and to take levothyroxine in the morning when waking up.
—ThyroidCancerHelp, September, 2007
Vocal cord damage
The recurrent laryngeal nerves provide the stimulation that moves the vocal cords and permits speech. They usually run adjacent to the thyroid gland on both sides of the neck. During thyroid surgery, they can be cut, stretched, or otherwise damaged, resulting in a paralyzed vocal cord on that side. If only slightly damaged, the function can return within days or weeks; however, if persistent for several months it is likely to be permanent.
If one vocal cord is paralyzed, the quality of the voice is affected, although later compensation by the other vocal cord may result in improvement later on. If both cords are paralyzed, the vocal cords move to the middle of the airway and it is necessary for the surgeon to perform a tracheostomy (put a hole in the windpipe through the neck) so that the person can breathe.
There are three major factors that determine whether vocal cord paralysis will occur from thyroid surgery: 1) the expertise of the surgeon (the lower the expertise, the higher the risk of this problem), 2) the extent of the cancer (invasive cancers may eat into the nerve or may involve difficult surgery to remove, causing a greater chance of this problem), and 3) LUCK (good vs bad). Even the BEST surgeons see this problem in their patients sometimes.
—ThyroidCancerHelp, June, 2007
Vocal cord paralysis (loss of voice or breathing problems from)
Thyroid surgery entails risk that one or both recurrent laryngeal nerves (the nerves that supply each vocal cord; one on each side) can be damaged or destroyed. When this happens, the corresponding vocal cord becomes paralyzed.
If only one of the two nerves is damaged, and if the damage is very minor, the paralysis could improve over several weeks; however, often the damage is permanent and the vocal cord on that side will never work properly again. Sometimes, after several weeks or months, the voice seems to improve; however, this can be due to adjustment of the unaffected vocal cord, rather than recovery of the paralyzed one.
If both vocal cords become paralyzed from bilateral nerve damage, this can be a medical emergency. In this case, both vocal cords relax towards the middle of the windpipe and can block the passage of air and prevent proper breathing. If this happens, the proper treatment is to have a tracheostomy (a hole made in the throat, into the windpipe, to permit breathing). Certainly, if loss of voice is fairly complete, particularly if there seems to be some difficulty breathing, the person should undergo an IMMEDIATE evaluation to see if both vocal cords are paralyzed and determine if there is need for a tracheostomy.
The proper surgeon to make this assessment is usually an ENT (Ear, Nose, and Throat; otolaryngologist) surgeon. In some cases it may be wise to see a different surgeon than the one who did the surgery, particularly if that surgeon is reluctant to evaluate the condition (possibly worried that they caused the problem). If there is difficulty breathing, it would not be appropriate to wait for a clinic appointment and a trip to the Emergency Department may be in order.
—ThyroidCancerHelp, November, 2007
X
X-ray report interpretation
[It is difficult] to interpret the comments that radiologists make in describing the CT scan studies that they are interpreting. Unfortunately, providing a lexicon of radiology terms will not help members better understand radiology reports in the context of their care. It's far more effective to take the report and discuss it directly with your physician.
—ThyroidCancerHelp, December, 2007
XRT: risks
XRT is far from a walk in the park. I tell patients that it is a very difficult mountain to climb, but eventually the path down the other side becomes much easier. Side effects include: loss of salivary gland function (as it does with radioactive iodine also), neck thickening and stiffness, later effects radiation effects upon the spinal cord (unlikely if care is taken to avoid this area), temporary severe irritation of the throat that can make eating and drinking difficult, much later risks of thickening of the esophagus or trachea that causes narrowing, and much later potential risks of causing another cancer in the salivary glands. Such side effects seem to be extremely daunting, yet most people, given appropriate XRT, have only transient effects with temporary irritation of their throats. Given the potential for risks from this treatment (and from nearly every significant medical procedure, including surgery), the decision for such therapy should be taken only after careful consideration and consultation. Pregnancy can stimulate persistent thyroid cancers.
—ThyroidCancerHelp, June, 2007
XRT (time for recurrent tumors that do not take up iodine)
In situations in which properly prepared radioactive iodine scans are clearly negative in the neck region (no evidence of tumor taking up radioactive iodine), yet surgery reveals and removes recurrent tumor, it becomes clear that this recurrent tumor is incapable of taking up radioactive iodine. It is not possible for the surgeon to definitively clear the neck of microscopic disease, that will undoubtedly re-grow and possibly spread later on. Persistent measurable thyroglobulin levels, even in the presence of thyroglobulin antibodies, further supports the fact that there is persistent disease.
Under such circumstances, state-of-the-art management uses external beam radiotherapy (XRT) to the neck and superior mediastinum to prevent local disease to recur in the neck. Failing to do this will generally condemn the person to repeated neck surgeries (and potential complications) until they are no longer possible or the doctor gains sufficient wisdom to have XRT performed. Better sooner than later.
Continuous diagnostic xrays and ultrasounds to detect recurrent disease in the neck, knowing that this tumor will re-grow in this region, without utilizing XRT seems senseless.
The use of XRT for de-differentiated (not taking up radioactive iodine) recurrent neck tumors (after the surgeon removes the bulk of them) is appropriate, even in the case when the tumor has spread to the lung. Recurrent disease in the neck is much less well tolerated than tumors in the lung or in most other distant sites.
—ThyroidCancerHelp, June, 2007
Z
Zactima Clinical Trial
Zactima (also known as Vendetanib or ZD6474) is a drug produced by the AstraZeneca Pharmaceutical company and has had some reasonably good success in controlling progression of medullary thyroid cancer in several clinical trials. It does not typically "kill" tumor, but instead causes it to diminish slightly or stop growing. There are some side effects associated with treatment and not everyone will respond. If there is a response, the length of time that this will continue to work may be highly variable.
There are currently some additional clinical trials for using this in radioactive iodine-unresponsive thyroid cancers (papillary or follicular) that have spread and are growing beyond the ability for surgery or external beam radiation. As stated in earlier postings, the best way to find such clinical trials is through the PDQ database on the website of the National Cancer Institute of the National Institutes of Health.
—ThyroidCancerHelp, February, 2008