TSH suppression has been the gold standard in the treatment of thyroid cancer patients. just to review, TSH is produced by the pituitary gland in the brain, and tells your thyroid gland to make and release thyroid hormones into your bloodstream. so, if you are a person, like me, and have had your thyroid removed due to thyroid cancer, why would you need to have your TSH suppressed? i have shared this quote from my endocrinologist many times in previous blogs, but here it is again. " even the most brilliant surgeon can not possibly get all of the bits of thyroid cancer cells that may have escaped from a cancerous thyroid gland." i also have called these rogue thyroid cancer cells, " Sarah Palin" cells. if you have had your cancerous thyroid gland removed, and even had the RAI treatment dose, there still may be some thyroid cancer cells " hiding out" in your body somewhere. the ONLY cells that would respond to the TSH produced by the pituitary gland would be thyroid cancer cells, since the thyroid gland itself has been removed. you do NOT want to wake up these rogue thyroid cancer cells by a high TSH.
a normal TSH range can be slightly different, according to what lab does your blood analysis, and also varies a little from physician to physician. one value for a normal TSH range is : 0.4 to 5 milli-international units per liter ( mIU/L). if you have a high TSH value you are considered hypothyroid. if you have a low TSH, you may be considered hyperthyroid. this is somewhat confusing. but consider it this way. if you have a high TSH, your pituitary gland is sending out more TSH because your thyroid gland is not working properly. the pituitary just keeps on cranking it out, so to speak, trying to get the thyroid gland to make and produce thyroid hormones.
getting back to suppression values of TSH in the treatment of thyroid cancer. these are the " official" guidelines determined by the american thyroid association ( ATA) in 2009. they are as follows:
for INITIAL TSH suppression, for high and intermediate risk patients, the guidelines recommend that the initial TSH be below 0.1 mU/L. for low risk patients, that value should be slightly below the lower limit of normal, or 0.1-0.5mU/L.
for LONG TERM MANAGEMENT, the guidelines are as follows:( all numbers are expressed in mU/L)
* in patients with persistent disease, the serum TSH should be maintained below 0.1 indefinitely in the absence of specific contraindications ( i will talk about these later)
* in patients who are clinically and biochemically free of disease, but who presented with high risk disease, the recommendation is made to maintain TSH suppression therapy of 0.1-0.5 for five to ten years.
* in patients free of disease, and at low risk for recurrence, the TSH may be kept within the low normal range of 0.3-2.
* in patients who have not undergone ablation, who are clinically free of disease, and have undetectable suppressed serum Tg and normal neck ultrasound, the serum TSH may be allowed to rise to the low normal range of 0.3 to 2.
it is interesting to note, that according to the ATA, " about 85% of post op patients are considered low risk, according to guidelines." i am not going into the guidelines here, but if anyone is interested, this information on low, intermediate and high risk of persistent or recurrent disease is explained on the thyca.org website. this is a wonderful website, full of very interesting and informative information. if you are a thyroid cancer patient, i urge you to check this out if you have not already.
the question of do you keep your TSH suppressed or not, and at what value, is an important one. this is where a really good physician who has lots of experience dealing with thyroid cancer patients is essential. i see an endocrinologist, but there are some excellent physicians out there who have a lot of experience dealing with thyroid cancer patients who are not endocrinologists. do your homework. read other patient reviews as well as professional reviews. do not be afraid to switch doctors or get a second opinion. i will tell you a secret now. i went to FOUR different endocrinologists before i was able to find one that i felt confident would be able to help me. i have been seeing this doctor for the past 10 years or so. i drive four hours to see her, and i would not see anyone else. try not to get discouraged when you are trying to find a good physician who can successfully treat thyroid cancer. one reason that it is very important that you do find someone who is very knowledgeable about the treatment of thyroid cancer is because of the risks associated with a very low TSH.
in a paper by David S. Cooper, " an overview of long-term clinical consequences" from the division of endocrinology and metabolism at the John Hopkins University School of Medicine, written in 2010, states several risk factors of a suppressed TSH. Mr.Cooper does agree that TSH should be maintained at levels less than 0.1 in high risk patients ( stage III and IV). he states that lower risk patients should be allowed to have their TSH levels rise to normal levels after residual disease has been ruled out. where it gets complicated, is when the patient is older ( say, over 60) and has osteoporosis, cardiovascular disease, or diabetes and is at high risk.
about 10% of patients with differentiated thyroid cancer( remember, this refers to papillary and follicular, as well as their variants) will have a recurrence. in a small number of these patients, the outcome will be fatal. so which patients will require a full suppression of their TSH, and which patients will not? this study states that about 80% of all thyroid cancer patients are low risk and will not benefit from maintaining full suppression of their TSH. increasing age and other health conditions- especially heart issues, makes the decision about suppressing TSH a complicated one. a low or suppressed TSH value can cause heart arrhythmias (ex. atrial fibrillation) in an older person, or a person with existing heart issues or diabetes. there is also the risk associated with osteoporosis and a low or suppressed TSH.
complicating matters, is that in the John Hopkins paper, the author listed two studies where a very low or suppressed TSH was linked with a higher survival rate. this relates to those in the higher stages group( stage III and IV). so, the difficult question is, how does one treat the older patient with a higher stage thyroid cancer who has heart disease or osteoporosis? there is no definitive answer to this question. it is an individualized treatment plan made by an experienced physician with input and consideration of each patient.
thyroid cancer requires life long monitoring and treatment. i had thyroid cancer eight years ago and I still see my endocrinologist every six months, and receive ultrasounds of my neck and blood work. i get a bone density test every year. all these tests are coming up for me in august. my TSH has been suppressed since i had my surgery for thyroid cancer. my endocrinologist and i have discussed letting my TSH rise a little, but i had stage III thyroid cancer, so this is a somewhat risky decision for me. i plan on showing my endocrinologist the information from thyca.org about keeping the TSH suppressed for 5-10 years for high risk ( high stage) patients. i think i would feel better if my physician would agree to keep my TSH suppressed for a couple more years. this depends somewhat on the results of my bone density test. my heart function, thankfully, is fine- at least for now.
this is a complicated issue for just about everyone who is a thyroid cancer patient. just one more reason thyroid cancer is not the " good cancer." i hope that i have not muddied the water, so to speak. the bottom line is this: find an excellent physician who has experience in treatment and monitoring of thyroid cancer patients. and make sure that you are able to talk freely and ask questions about your treatment, and have input with your doctor.
No comments:
Post a Comment