T3 T4 Tsh And Thyroid Cancer: What You Really Need To Know
Let me preface this post by clearly stating, I am not a medical doctor. I am simply a thyroid cancer survivor, well-read and well-informed. Always consult your physician about any medical information you have come across.
Im going to try to keep this info simple. If you have any questions about what I have posted, please, leave a comment. I will try to address it.
What the thyroid does: it produces the hormones T3 & T4.
What happens when you remove the thryoid: you need to replace the T4 hormone.
Why not replace the T3 hormone: your body will convert T4 to T3.
What is TSH: ThyroidStimulating Hormone.
Why is TSH important: in papillary and follicular thyroid cancers, TSH suppression is an integral part of preventing thyroid cancer recurrence.
I keep reading that I should only focus on the T3 and T4 levels to decide if I am hypo or hyper thyroid: that is incorrect. You no longer have a thyroid, you are fully dependent on an oral T4 pill. If you do not take your T4 pill your body has no way to produce T4 . You do not have a thyroid, so you do not have a malfunctioning thyroid. You are not hyper or hypo thyroid if you are taking your pill, daily. You should ALWAYS focus on your TSH, that is the integral part of your thyroid cancer management, for the rest of your life.
But I have symptoms: your dose can be too high or too low and there are symptoms that go along with that.
Association Between Serum Tsh And Differentiated Thyroid Cancer Stage
Haymart et al. demonstrated that higher preoperative serum TSH concentrations were not only associated with the incidence of differentiated thyroid cancer, but also with more advanced cancer stage at diagnosis. Mean serum TSH levels were significantly higher in those with stage III and IV disease when compared with those with more localised disease . In this month’s issue, Fiore et al. confirm the finding of higher serum TSH in patients with T3T4 tumour stage compared with those with stage T1T2. Furthermore, median serum TSH concentrations were significantly higher in those with lymph node metastases compared with subjects without positive lymph nodes . This escalating risk of advanced disease further suggests that TSH is involved in the pathogenesis or progression of thyroid cancer.
Treatment Of Advanced Thyroid Cancer
Thyroid cancer that spreads outside the neck area is rare, but can be a serious problem. Surgery and radioactive iodine remain the best way to treat such cancers as long as these treatments continue to work. However, for more advanced cancers, or when radioactive iodine therapy is no longer effective, other forms of treatment are needed. External beam radiation directs precisely focused X-rays to areas that need to be treatedoften tumor that has recurred locally or spread to bones or other organs. This can kill or slow the growth of those tumors. Cancer that has spread more widely requires additional treatment.
New chemotherapy agents that have shown promise treating other advanced cancers are becoming more widely available for treatment of thyroid cancer. These drugs rarely cure advanced cancers that have spread widely throughout the body but they can slow down or partially reverse the growth of the cancer. These treatments are usually given by an oncologist and often require care at a regional or university medical center.
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External Beam Radiation Therapy
While it remains the standard of care in many cancers of the head and neck, external beam radiation therapy is not often recommended for the treatment of thyroid cancer. For well-differentiated thyroid cancers, radioactive iodine therapy is preferred, because it is a more targeted form of radiation that attacks only thyroid cells and has fewer side effects. However, in select patients with aggressive cases of thyroid cancer that do not take up iodine and/or present with recurrent disease, adjuvant external beam radiation therapy may be considered.
What Is The Treatment For Thyroid Cancer
Surgery. The primary therapy for all types of thyroid cancer is surgery . The extent of surgery for differentiated thyroid cancers will depend on the size of the tumor and on whether or not the tumor is confined to the thyroid. Sometimes findings either before surgery or at the time of surgery such as spread of the tumor into surrounding areas or the presence of obviously involved lymph nodes will indicate that a total thyroidectomy is a better option. Some patients will have thyroid cancer present in the lymph nodes of the neck . These lymph nodes can be removed at the time of the initial thyroid surgery or sometimes, as a later procedure if lymph node metastases become evident later on. For very small cancers that are confined to the thyroid, involving only one lobe and without evidence of lymph node involvement a simple lobectomy is considered sufficient. Recent studies even suggest that small tumors called micro papillary thyroid cancers may be observed without surgery depending on their location in the thyroid. After surgery, most patients need to be on thyroid hormone for the rest of their life . Often, thyroid cancer is cured by surgery alone, especially if the cancer is small. If the cancer is larger, if it has spread to lymph nodes or if your doctor feels that you are at high risk for recurrent cancer, radioactive iodine may be used after the thyroid gland is removed.
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Physiology Of Thyroid Hormone
Thyroid hormone plays a critical role in the development and function of virtually every organ system in humans., This process is stimulated by TSH. The anterior pituitary releases TSH in response to thyroid-releasing hormone, which is secreted by the hypothalamus. The thyroid gland secretes both thyroxine and triiodothyronine , which exert a negative feedback on TSH releasing hormone and TSH secretion.,
The thyroid gland secretes mainly T4, which is deiodinated intracellularly to the active hormone T3 which then binds to thyroid hormone receptors and functions as a transcription factor for many cellular processes. In the absence of a thyroid gland, exogenous L-T4 is efficiently converted to T3. Serum T3 levels remain stable after L-T4 administration but vary widely after oral administration of liothyronine . Moreover, L-T4 is a better regulator of TSH secretion as it is more likely than T3 to pass the bloodbrain barrier. This is why L-T4 has been the drug of choice for long-term treatment of athyreotic individuals.
Patients Unable To Achieve A Suppressed Tsh Despite Proper Thyroid Hormone Therapy
There are some patients on adequate or even high doses of thyroid hormone therapy who are unable to achieve TSH suppression. The differential diagnoses include malabsorption, non-compliance, factors increasing the medications metabolism, or increased serum levels of T4-binding globulin. In addition, when the TSH cannot be suppressed in spite of adequate doses of thyroid hormone, the physician should consider the presence of heterophile antibodies and interference with the laboratory measurement including anti-mouse antibodies, rheumatoid factor, and autoimmune anti-TSH antibodies. Finally one could consider the coexistence of adrenal insufficiency, which may induce TSH elevation reversible with glucocorticoid replacement.
Defects in thyroid hormone absorption are rare without a history of previous gut surgery, celiac disease, lactose intolerance, autoimmune gastritis, or Helicobacter pylori infection. A serum free T4 peak at 2 hours rising above the upper limit of normal after the administration of 100 g of L-T4 suggests proper absorption, but unfortunately there are no well-established standards for this test. A radioisotope-labeled L-T4 tracer technique may be used to test absorption more accurately, but this technique is not readily available. Prior studies looking into this matter have shown that oftentimes patients suspected to have absorption problems actually exhibit a factitious disorder and have compliance issues.
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Dissenting Opinions On Suppressing And Replacing Tsh
“It turns out that most individuals with differentiated thyroid cancer are at low risk to begin with, and don’t have residual ,” he said. So there would be no reason to maintain a low TSH level in these patients. However, for the small fraction of patients with more advanced thyroid cancers, there is some evidence that TSH therapy might result in an improved outlook. But for the vast majority of patients, TSH therapy really wont matter,” Dr. Cooper told EndocrineWeb.
Among the many studies cited by Dr. Cooper is a meta-analysis of 10 studies on which the researchers concluded that suppression therapy helped reduce morbidity and mortality for adverse events pertaining to combined disease progression/recurrence and death. However, these older studies failed to differentiate thyroid hormone replacement from thyroid hormone suppression and, modern technology such as ultrasound and thyroglobulin measurement were also lacking, he said.
Results of studies falling under the umbrella of the National Thyroid Cancer Treatment Cooperative Study Group suggest that the most aggressive suppression therapy ”was of no value in patients at low risk for recurrence but was of benefit in high-risk patients.”3,4
Potential adverse events to consider include effects of suppressive therapy with levothyroxine. When patients with DTC were given excessive L-T4 doses, serum free thyroxine was often at the upper limit of the reference range or even elevated.6-8
Doctor Visits And Follow
Your health care team will explain what tests you need and how often they should be done. Your schedule of doctor visits, exams, and tests will depend on the original extent of your cancer, the specific type of thyroid cancer you had, how it was treated, and other factors.
Papillary or follicular cancer: If you have had papillary or follicular cancer, and your thyroid gland has been completely removed or ablated, your doctors may consider at least one radioactive iodine scan after treatment, especially if you are at higher risk for recurrence. This is usually done about 6 to 12 months later. If the result is negative, you will generally not need further scans unless you have symptoms or other abnormal test results.
Your blood will also be tested regularly for TSH and thyroglobulin levels. Thyroglobulin is made by thyroid tissue, so after total thyroid removal and ablation it should be at very low levels or not be found in your blood at all. If the thyroglobulin level begins to rise, it might be a sign the cancer is coming back, and further testing will be done. This usually includes a radioactive iodine scan, and may include PET scans and other imaging tests.
For those with a low-risk, small papillary cancer that was treated by removing only one lobe of the thyroid, routine physical exams by your doctor, thyroid ultrasounds and thyroid blood tests are typical.
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How Is Thyroid Cancer Diagnosed
Most people who are eventually diagnosed with thyroid cancer first come to their doctor after noticing a lump in their neck, so the diagnostic process usually starts with an evaluation of this nodule. The first step is a medical history and physical exam from a medical professional. Blood and imaging tests for thyroid cancer may follow. A thyroid biopsy is used to confirm the diagnosis of thyroid cancer.
Thyroid Hormone Suppression For Thyroid Cancer
After evaluating the amassed evidence for and against suppression therapy, and factoring in potential adverse effects, Dr. Cooper said since the average patient with DTC is at low risk for recurrence, the takeaway message for clinicians is that the TSH for these patients does not need to be suppressed.
The goal should be to achieve a TSH level at the low end of the normal range, he told EndocrineWeb. As such, Dr. Cooper suggests following the graded algorithm cited in the American Thyroid Association guidelines with consideration given to the potential for benefits of therapy balanced against any individual cardiovascular and skeletal risks.10
According to the ATA guidelines,10 serum TSH levels should be maintained between 0.5 and 2 mU/L in low and intermediate risk patients with the expectation of an excellent response to treatment. Mild TSH suppression is recommended when TSH is at 0.1 to 0.5 mU/L in high risk patients with excellent response, meaning negative imaging and undetectable suppressed thyroglobulin.
Mild suppression is also recommended for patients with a biochemically incomplete response. In particular, patients with residual structural disease or a biochemically incomplete response if they are young or at low risk of complications may need more robust TSH suppressionto less than 0.1 mU/L but not necessarily undetectable.10
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Tsh Suppression: More Harm Than Good After Cancer Surgery
This article is a collaboration between MedPage Today and:
SAN JUAN — Suppressing thyroid-stimulating hormone after thyroidectomy for low-risk cancer increases the risk of osteoporosis in women without cutting back on cancer recurrence, researchers reported here.
In a retrospective study, women who had suppressed TSH levels had more than a three-fold increased risk of osteoporosis than those whose levels were not suppressed, Laura Wang, MD, of Memorial Sloan Kettering Cancer Center in New York City, and colleagues reported at the American Thyroid Association meeting.
- This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
“Therapeutic efforts should focus on avoiding harm in indolent disease,” Wang said during her presentation.
After thyroidectomy for well-differentiated thyroid cancer, TSH is often suppressed because it stimulates thyroid cell proliferation, and a goal of treatment is to inhibit the growth of residual neoplastic tissue.
But there’s no evidence-based consensus on the optimal TSH level that can help reduce recurrence while minimizing the risk of adverse effects, Wang said.
They excluded patients with high-risk cancer, those with primary hyperparathyroidism, and those who had atrial fibrillation or osteoporosis before thyroidectomy.
TSH suppression was defined as a median level of 0.4 mU/L or less.
Does Thyroxine Treatment Have Side Effects
No good-quality research is available on the side effects of treating subclinical hypothyroidism with thyroxine, but its generally considered to be a well-tolerated drug. Because the body usually produces this hormone on its own, there are no problems if the dose is correct. If its too high though, side effects cant be ruled out. Possible side effects include heart problems like or a racing heartbeat.
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The Thyroid: What Your Tsh Number Means
In our last blog we talked about some of the things that can happen when your thyroid is sluggish or overactive. Today were going to talk about the TSH test and its results. TSH stands for Thyroid Stimulating Hormone a standard blood test will produce a number of how well your thyroid is performing. Normal range for an adult is typically considered to be between .4 and 4.0 however, in my practice I would say ideal is between 0.5 and 1.5.
In my experience with patients, Ive found that symptoms begin to occur in my patients well within the typically accepted range of 0.4 and 4.0 in fact, if the TSH level is over 1.5 or 2.0, I consider that to be a sign that the thyroid isnt working well enough. It would be easy to think that if your TSH level was higher it would be a sign that youre doing ok however, when the thyroid is underactive your body compensates for this sending your TSH levels skyrocketing. So even though your number might look okay in the generally accepted range, its a sign that imbalance is occurring.
If youre feeling poorly all the time and think your thyroid might having some trouble, ask your doctor for a TSH test .
Thyroid Removal Or Thyroid Deactivation
If you have had surgery to remove your thyroid or radioiodine therapy to deactivate your thyroid, you will receive regular T4 replacement therapy. This usually affects TSH levels secreted by your pituitary gland as your medication is monitored and adjusted.
The journal Rambam Maimonides says that low levels of T3 and T4 exert a negative feedback on TSH and signals to your body to increase TSH levels. When receiving levothyroxine therapy, your TSH levels and T4 levels will be closely monitored to make sure that T4 levels dont drop dangerously low.14
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Low Levels Of The Hormone
If the hormone TSH lowered that this could mean? In the case of low thyroid-stimulating hormone, there is a disruption in the thyroid. In addition, the low TSH could be a sign of the presence of benign thyroid tumors, meningitis, encephalitis and other diseases. The lack of substance in women causes constant headaches, chronic fatigue, ucashenie pulse, the appearance of the swelling on the face, disruptions of the menstrual cycle.
Preparing For Radioactive Iodine Treatment For Thyroid Cancer
Radioactive iodine treatment is a type of internal radiotherapy. It uses a radioactive form of iodine called iodine 131 . It is a useful treatment in thyroid cancer because the thyroid gland absorbs and stores most of the iodine in your body. The thyroid gland gets iodine from certain foods and uses this to make essential thyroid hormones.
Radioactive iodine is a targeted treatment. The radioactive iodine circulates throughout your body in your bloodstream. But it is mainly taken up by thyroid cells, having little effect on other cells. Thyroid cancer cells in your body pick up the iodine. The radiation in the iodine then kills the cancer cells.
It is only suitable for some types of thyroid cancer. It is a treatment for:
- follicular thyroid cancer
- papillary thyroid cancer
It can treat the cancer even if it has spread. But even if you have one of these types of thyroid cancer, this treatment may not be necessary or suitable for you. Not all of the cancer cells take up the iodine so you may have a test dose to see if they do.
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