Types of Thyroid Cancer
* Thyroid Cancer Overview
* Anaplastic Thyroid Cancer
* Follicular Thyroid Cancer
* Medullary Thyroid Cancer
* Hurthle Cell Thyroid Cancer
* Papillary Thyroid Cancer
Symptoms of thyroid cancer
Occasionally, symptoms such as hoarseness, neck pain, and enlarged lymph nodes do occur in people with thyroid cancer. Although as much as 75% of the population will have thyroid nodules, the vast majority are benign. Young people usually don't have thyroid nodules, but as people age, they likely develop a nodule. By the time we are 80, 90% of us will have at least one nodule.
Far less than 1% of all thyroid nodules are malignant. A nodule that is cold on scan (shown in photo outlined in red and yellow) is more likely to be malignant. Nevertheless, the majority of these are benign as well. You can read more information about thyroid nodules and their potential to be malignant below:
Introduction to Thyroid Nodules
Basic Facts about Thyroid Nodules
Simply put, thyroid nodules are lumps that commonly arise within an otherwise normal thyroid gland. Often these abnormal growths of thyroid tissue are located at the edge of the thyroid gland, so they can be felt as a lump in the throat. When they are large or when they occur in very thin individuals, they can even sometimes be seen as a lump in the front of the neck. The following is a list of facts regarding thyroid nodules:
* One in 12 to 15 young women has a thyroid nodule.
* One in 40 young men has a thyroid nodule.
* More than 95% of all thyroid nodules are benign (non-cancerous growths).
* Some are actually cysts, which are filled with fluid rather than thyroid tissue.
* Most people will develop a thyroid nodule by the time they are 50 years old.
* The incidence of thyroid nodules increases with age.
o 50% of 50 year olds will have at least one thyroid nodule.
o 60% of 60 year olds will have at least one thyroid nodule.
o 70% of 70 year olds will have at least one thyroid nodule.
Three Questions about Thyroid Nodules
1. Is the nodule one of the few that are cancerous?
2. Is the nodule causing trouble by pressing on other structures in the neck?
3. Is the nodule making too much thyroid hormone?
After an appropriate work-up, most thyroid nodules will yield an answer of no to all of the above questions. In this most common situation, there is a small- to moderate-sized nodule that is simply an overgrowth of normal thyroid tissue, or even a sign that there is too little hormone being produced.
Patients with a diffusely enlarged thyroid (called a goiter) will have what is perceived at first to be a nodule but is later found to be only one of many benign enlarged growths within the thyroid (a goiter).
Usually a fine needle aspiration biopsy (FNA) will tell if the nodule is cancerous or benign. This one test can get right to the bottom of the issue. Often an ultrasound is necessary to determine the characteristics of a thyroid nodule.
If any of the above questions are answered yes, then medical or surgical treatment is required.
Symptoms of Thyroid Nodules
Most thyroid nodules cause no symptoms at all. They are usually found by patients who feel a lump in their throat or see it in the mirror. Occasionally, a family member or friend will notice a strange lump in the neck of someone with a thyroid nodule. Another common way in which thyroid nodules are found is during a routine examination by a physician.
Occasionally, nodules may cause pain, and even rarer still are those patients who complain of difficulty swallowing when a nodule is large enough and positioned in such a way that it impedes the normal passage of food through the esophagus (which lies behind the trachea and thyroid).
Sometimes, a thyroid nodule is found because the patient is undergoing a CT scan, MRI scan, or ultrasound scan of the neck for some other reason (such as parathyroid disease, carotid artery disease, or cervical spine pain). Thyroid nodules found this way (by accident) are cancerous far less than 1% of the time.
What to Do if You Have a Nodule
Remember that the vast majority of thyroid nodules are benign. The nodule should be evaluated by a physician who is comfortable with this problem. Endocrinologists and endocrine surgeons deal with these problems on a regular basis, but many family practice physicians, general internists, and general surgeons are also adept at addressing thyroid nodules. This is covered in more detail on our nodule exam/biopsy page.
One of the first things a physician should do is ask a number of important questions regarding your health and potential thyroid problems. These questions include whether you have been exposed to nuclear radiation or received radiation treatments as a child or teenager.
What about Radiation Exposure?
Ionizing radiation has been known for a number of years to be associated with a small increased risk of developing thyroid cancer. The risk is very small and the amount of radiation exposure is usually quite high. There is typically a delay of 20 years or more between radiation exposure and the development of thyroid cancer.
Radiation was used occasionally between the 1920s and 1950s to treat certain neck infections, such as recurrent tonsillitis and certain skin conditions (such as severe acne).
In July 1997, the US government announced the results of a scientific study to determine if nuclear weapons testing in the southeast US from 1945 through the 1970s would have an effect on the development of thyroid cancer in Americans. This epidemiological study determined that these nuclear tests would likely increase the amount of thyroid cancers seen in Americans over the next several decades. The risks are substantially greater for those patients living nearby the test sites for many years. If there is any good news to this report, it is that these cancers will typically be of the well-differentiated type that have an excellent prognosis. The vast majority of these can be cured. There is no evidence that children are at increased risk of developing thyroid cancer; the small increase risk appears to be limited to those who were directly exposed in the past. Despite these increased risks, thyroid cancer is still relatively uncommon and usually very curable.
The Workup of Thyroid Nodules and the Role of Fine Needle Aspiration Biopsy (FNA)
Solitary dominant nodule of right thyroid lobeThyroid nodules increase with age and are present in almost 10% of the adult population. Autopsy studies reveal the presence of thyroid nodules in 50% of the population, so they are fairly common. 95% of solitary thyroid nodules are benign, and therefore, only 5% of thyroid nodules are malignant.
Common types of the benign thyroid nodules are adenomas (overgrowths of normal thyroid tissue), thyroid cysts, and Hashimoto's thyroiditis.
Uncommon types of benign thyroid nodules are due to subacute thyroiditis, painless thyroiditis, unilateral lobe agenesis, or Riedel's struma. As noted on previous pages, those few nodules that are cancerous are usually due to the most common types of thyroid cancers that are the differentiated thyroid cancers. Papillary carcinoma accounts for 60%, follicular carcinoma accounts for 12%, and the follicular variant of papillary carcinoma accounts for 6%. These well differentiated thyroid cancers are usually curable, but they must be found first. Fine needle biopsy is a safe, effective, and easy way to determine if a nodule is cancerous.
Thyroid cancers typically present as a dominant solitary nodule that can be felt by the patient or even seen as a lump in the neck by his/her family and friends. This is illustrated in the picture above.
As pointed out on our page introducing thyroid nodules, we must differentiate benign nodules from cancerous solitary thyroid nodules. While history, examination by a physician, laboratory tests, ultrasound, and thyroid scans (shown in the image on the right) can all provide Solitary cold nodule of thyroidinformation regarding a solitary thyroid nodule, the only test that can differentiate benign from cancerous thyroid nodules is a biopsy (the term biopsy means to obtain a sample of the tissue and examine it under the microscope to see if the cells have taken on the characteristics of cancer cells).
Thyroid cancer is no different in this situation from all other tissues of the body; the only way to see if something is cancerous is to biopsy it. However, thyroid tissues are easily accessible to needles, so rather than operating to remove a chunk of tissue with a knife, we can stick a very small needle into it and remove cells for microscopic examination. This method of biopsy is called a fine needle aspiration biopsy (FNA).
What is a Cold or Hot Nodule?
Nodules detected by thyroid scans are classified as cold, hot, or warm. Thyroid cells absorb iodine so they can make thyroid hormone out of it. When radioactive iodine is given, a butterfly image will be obtained on x-ray film showing the outline of the thyroid. If a nodule is composed of cells that do not make thyroid hormone (don't absorb iodine), then it will appear "cold" on the x-ray film. A nodule that is producing too much hormone will show up darker and is called "hot."
85% of thyroid nodules are cold, 10% are warm, and 5% are hot. Remember that 85% of cold nodules are benign, 90% of warm nodules are benign, and 95% of hot nodules are benign.
Although thyroid scanning can give a probability that a nodule is benign or malignant, it cannot truly differentiate benign or malignant nodules and usually should not be used as the only basis for recommending treatment of the nodule, including thyroid surgery.
The evaluation of a solitary thyroid nodule should always include history and examination by a physician. Certain aspects of the history and physical exam will suggest a benign or malignant condition. Remember, a biopsy of some sort is the only way to tell for sure.
The Following Features Favor a Benign Thyroid Nodule:
* Family history of Hashimoto's thyroiditis
* Family history of benign thyroid nodule or goiter
* Symptoms of hyperthyroidism or hypothyroidism
* Pain or tenderness associated with a nodule
* A soft, smooth, mobile nodule
* Multi-nodular goiter without a predominant nodule (lots of nodules, not one main nodule)
* "Warm" nodule on thyroid scan (produces normal amount of hormone)
* Simple cyst on an ultrasound
The Following Features Increase the Suspicion of a Malignant Nodule:
* Age less than 20
* Age greater than 70
* Male gender
* New onset of swallowing difficulties
* New onset of hoarseness
* History of external neck irradiation during childhood
* Firm, irregular, and fixed nodule
* Presence of cervical lymphadenopathy (swollen, hard lymph nodes in the neck)
* Previous history of thyroid cancer
* Nodule that is "cold" on scan (shown in picture above, meaning the nodule does not make hormone)
* Solid or complex on an ultrasound
Thyroid hormone levels are usually normal in the presence of a nodule, and normal thyroid hormone levels do not differentiate benign from cancerous nodules. However, the presence of hyperthyroidism or hypothyroidism favors a benign nodule (that's why a "warm" or a "hot" nodule favors a benign condition).
Thyroglobulin levels are useful tumor markers once the diagnosis of malignancy has been made, but they are non-specific in regard to differentiating a benign from a cancerous thyroid nodule.
Ultrasound accurately determines thyroid gland volume, number, and size of nodules, separates thyroid from nonthyroidal masses, helps guide fine needle biopsy when necessary, and can identify solid nodules as small as 3mm and cystic nodules as small as 2mm.
Although several ultrasound features favor the presence of a benign nodule, and other ultrasound features favor the presence of a cancerous nodule, ultrasound alone cannot differentiate benign from malignant nodules. This is covered more completely on our nodule/ultrasound page. And since 15% of cystic thyroid nodules are malignant, ultrasound determination that a nodule is cystic does not rule out thyroid cancer.
Thyroid fine needle aspiration (FNA) biopsy is the only non-surgical method that can differentiate malignant and benign nodules in most, but not all, cases. The needle is placed into the nodule several times and cells are aspirated into a syringe. The cells are placed on a microscope slide, stained, and examined by a pathologist. The nodule is then classified as non-diagnostic, benign, suspicious, or malignant.
* Non-diagnostic indicates that there are an insufficient number of thyroid cells in the aspirate and no diagnosis is possible. A non-diagnostic aspirate should be repeated, as a diagnostic aspirate will be obtained approximately 50% of the time when the aspirate is repeated. Overall, 5 to 10% of biopsies are non-diagnostic, and the patient should then undergo either an ultrasound or a thyroid scan for further evaluation.
* Benign thyroid aspirations are the most common (as we would suspect since most nodules are benign) and consist of benign follicular epithelium with a variable amount of thyroid hormone protein (colloid).
* Malignant thyroid aspirations can diagnose the following thyroid cancer types: papillary, follicular variant of papillary, medullary, anaplastic, thyroid lymphoma, and metastases to the thyroid. Follicular carcinoma and Hurthle cell carcinoma cannot be diagnosed by FNA biopsy. This is an important point. Since benign follicular adenomas cannot be differentiated from follicular cancer (~12% of all thyroid cancers) these patients often end up needing a formal surgical biopsy, which usually entails removal of the thyroid lobe that harbors the nodule.
* Suspicious cytologies make up approximately 10% of FNAs. The thyroid cells on these aspirates are neither clearly benign nor malignant. 25% of suspicious lesions are found to be malignant when these patients undergo thyroid surgery. These are usually follicular or Hurthle cell cancers. Therefore, surgery is recommended for the treatment of thyroid nodules from which a suspicious aspiration has been obtained.
FNA is the first, and in the vast majority of cases, the only test required for the evaluation of a solitary thyroid nodule. (A TSH value should also be obtained to evaluate thyroid function.) Thyroid ultrasound and thyroid scans are usually not required for evaluation of a solitary thyroid nodule. FNA has reduced the cost for evaluation and treatment of thyroid nodules and has improved yield of cancer found at thyroid surgery. Although a solitary thyroid nodule can enlarge or shrink over time, the natural history of solitary nodules reveals that most nodules change little with time.
Can I Make the Nodule Go Away by Taking Thyroid Hormone?
Several studies reveal that suppression with thyroid hormone does not decrease the size of thyroid nodules. Therefore, unless a nodule is growing or becoming symptomatic, it is not necessary to suppress the nodule. In addition, suppression of a thyroid nodule would require long-term thyroid-stimulating hormone (TSH) suppression, potentially increasing the risk of osteoporosis in these patients.
While there has been a traditional distinction between thyroid glands with a solitary nodule and multi-nodular goiters, it has been shown that approximately 50% of patients with a solitary nodule on exam will have additional nodules on thyroid ultrasound. Therefore, the differentiation between solitary nodules and multinodular goiters is becoming less clear-cut.
It has also been believed for many years that the presence of a multinodular goiter reduces the likelihood that a thyroid cancer is present, yet recent studies indicate that there might be an equal likelihood for developing thyroid cancer in a multinodular goiter just as in a solitary thyroid nodule. If a multinodular goiter has a predominant nodule, the predominant nodule should be biopsied.
In conclusion, FNA of the thyroid is a safe, inexpensive, and effective way to distinguish a benign from a malignant nodule and usually should be the first diagnostic test performed.
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The Role of Thyroid Ultrasound and What It Means
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Once a thyroid nodule has been detected (or suspected), there are a few things that the physician will want to know before any recommendations can be made regarding treatment. Remember, the vast majority of thyroid nodules are benign and nothing to worry about, so the focus is on determining which ones have any reasonable chance of being cancerous. It is those few worrisome nodules that will need to be operated upon with that portion of the thyroid removed.
One of the first tests that is routinely performed is the fine needle aspiration biopsy. The FNA will usually (but not always) tell if a nodule is benign or malignant. This is often the only test needed.
Another common test is the ultrasound. This simple test uses sound waves to image the thyroid. The sound waves are emitted from a small hand-held transducer that is passed over the thyroid. A lubricant jelly is placed on the skin so that the sound waves transmit more easily through the skin and into the thyroid and surrounding structures. This test is quick, accurate, cheap, painless, and completely safe. It usually takes only about 10 minutes and the results can be known almost immediately. Not all nodules need this test, but it is almost routine.
Ultrasound Characteristics That Suggest a Benign Nodule
* Sharp edges are seen all around the nodule
* Nodule filled with fluid and not live tissue (a cyst)
* Lots of nodules throughout the thyroid (almost always a benign multi-nodular goiter)
* No blood flowing through it (not live tissue, likely a cyst)
* More on this topic on our FNA page
Thyroid nodule with excess blood flowTo illustrate some of these points, the picture on the right shows the same ultrasound as above, but this time the probe is programmed to detect blood flow. You can now clearly see that this nodule is complex, which means that some of it is cystic, while other parts are comprised of live tissues that have a good blood supply. If this were a simple cyst filled with serous fluid, then it would have no red (artery) or blue (vein) blood flow.
This patient had no other nodules in her thyroid, so this was diagnosed as a "dominant complex nodule of the right thyroid lobe."
Since this nodule does have a few worrisome characteristics, a fine needle aspirate biopsy (FNA) was performed. In this test, a very small needle is passed into the nodule and some cells are aspirated out and then placed on a glass slide for a pathologist to stain and determine if they are malignant.
This test is very simple; it takes less than 30 seconds, is virtually pain free, and can be very accurate. If it is read as cancer, this test is almost always right.
Sometimes, however, there are not enough cells removed or some, but not all, cells look abnormal. In this case, the pathologist will not be able to tell cancer from a benign nodule. This situation usually dictates that the test be repeated or that the patient undergo surgical removal of this part of the thyroid. Remember, the vast majority of nodules are benign, and even if it is cancer, most thyroid cancers are extremely curable.
This patient had two indeterminate FNAs performed. Both needle biopsies had good tissue specimens, but the pathologist could not distinguish benign from cancer. She subsequently underwent a simple right thyroid lobectomy, and the final diagnosis was a benign follicular adenoma. She did fine after the operation and has enough normal thyroid still in her neck, so she does not have to take thyroid hormone pills
Thyroid Cancer Type and Incidence
* Papillary and/or mixed papillary/follicular
* Follicular
* Medullary
* Anaplastic
Note: Chief Justice William Rehnquist had anaplastic thyroid cancer. After reading this overview page on thyroid cancer, click here to read more about Chief Justice William Rehnquist and his classic battle with the worst kind of thyroid cancer.
What's the Prognosis?
Most thyroid cancers are very curable. In fact, the most common types of thyroid cancer (papillary and follicular) are the most curable. In younger patients, both papillary and follicular cancers have a more than 97% cure rate if treated appropriately. Both papillary and follicular cancers are typically treated with complete removal of the lobe of the thyroid that harbors the cancer, in addition to the removal of most or all of the other side.
The bottom line is that most thyroid cancers are papillary thyroid cancer, and this is one of the most curable cancers of all cancers that humans get. Treated correctly, the cure rate is extremely high.
Medullary cancer of the thyroid is significantly less common, but has a worse prognosis. Medullary cancers tend to spread to large numbers of lymph nodes very early on, and therefore require a much more aggressive operation than the more localized thyroid cancers, such as papillary and follicular. This cancer requires complete thyroid removal plus a dissection to remove the lymph nodes of the front and sides of the neck.
The least common type of thyroid cancer is anaplastic which has a very poor prognosis. Anaplastic thyroid cancer tends to be found after it has spread and is incurable in most cases. It is very uncommon to survive anaplastic thyroid cancer, as often the operation cannot remove all the tumor. These patients often require a tracheostomy during the treatment, and treatment is much more aggressive than for other types of thyroid cancer--because this cancer is much more aggressive.
What About Chemotherapy?
Thyroid cancer is unique among cancers. In fact, thyroid cells are unique among all cells of the human body. They are the only cells that have the ability to absorb iodine. Iodine is required for thyroid cells to produce thyroid hormone, so they absorb it out of the bloodstream and concentrate it inside the cell.
Most thyroid cancer cells retain this ability to absorb and concentrate iodine. This provides a perfect "chemotherapy" strategy. Radioactive Iodine is given to the patient with thyroid cancer after their cancer has been removed. If there are any normal thyroid cells or thyroid cancer cells remain in the patient's body (and any thyroid cancer cells retaining this ability to absorb iodine), then these cells will absorb and concentrate the radioactive "poisonous" iodine. Since all other cells of our bodies cannot absorb the toxic iodine, they are unharmed. The thyroid cancer cells, however, will concentrate the poison within themselves and the radioactivity destroys the cell from within. No sickness. No hair loss. No nausea. No diarrhea. No pain.
Most, but not all, patients with thyroid cancer need radioactive iodine treatments after their surgery. This is important to know. Almost all, however, should have the iodine treatment if a cure is to be expected.
Patients with medullary cancer of the thyroid usually do not need iodine therapy because medullary cancers almost never absorb the radioactive iodine. Some small papillary cancers treated with a total thyroidectomy may not need iodine therapy as well, but for a different reason.
These cancers (medullary and some small papillary cancers) are often cured with simple (complete) surgical therapy alone. This varies from patient to patient and from cancer to cancer. This decision will be made between the surgeon, the patient, and the referring endocrinologist or internist. Remember, radioactive iodine therapy is extremely safe. If you need it, take it.
Overview of Typical Thyroid Cancer Treatment
1. Thyroid cancer is usually diagnosed by sticking a needle into a thyroid nodule or removal of a worrisome thyroid nodule by a surgeon.
2. The removed thyroid nodule is looked at under a microscope by a pathologist who will then decide if the nodule is benign (95-99% of all nodules that are biopsied) or malignant (less than 1% of all nodules, and about 1-5% of nodules that are biopsied).
3. The pathologist decides the type of thyroid cancer: papillary, follicular, mixed papilofollicuar, medullary, or anaplastic.
4. The entire thyroid is surgically removed; sometimes this is done during the same operation where the biopsy takes place. He/she will assess the lymph nodes in the neck to see if they also need to be removed. In the case of anaplastic thyroid cancer, your doctor will help you decide about the possibility of a tracheostomy.
5. About 4-6 weeks after the thyroid has been removed, the patient will undergo radioactive iodine treatment. This is very simple and consists of taking a single pill in a dose that has been calculated for the patient. The patient goes home and avoids contact with other people for a couple of days (so they are not exposed to the radioactive materials).
6. A week or two after the radioactive iodine treatment the patient begins taking a thyroid hormone pill. No one can live without thyroid hormone, and if the patient doesn't have a thyroid anymore, he or she will take one pill per day for the rest of their life. This is a very common medication (examples of branded drug names include Synthroid, Levoxyl, and Armour Thyroid).
7. Every 6-12 months the patient returns to his endocrinologist for blood tests to determine if the dose of daily thyroid hormone is correct and to make sure that the thyroid tumor is not coming back. The frequency of these follow up tests will vary greatly from patient to patient. Endocrinologists are typically quite good at this and will typically be the type of doctor that follows this patient long-term.
Patient’s Guide to Thyroid Cancer and Hypothyroidism
Hypothyroidism considerations after thyroid cancer surgery
Indication
Thyrogen (thyrotropin alfa for injection) is indicated for use as an additional tool to identify thyroid disease (by testing the blood for a hormone called thyroglobulin), with or without a radiology test using a form of iodine, in the follow-up of patients with a certain type of thyroid cancer (known as well-differentiated thyroid cancer).
Thyrogen (thyrotropin alfa for injection) is also indicated for use as a preparation for treatment with a form of iodine to remove left over thyroid tissue in patients who have had surgery to take out the entire thyroid gland for a certain type of thyroid cancer (known as well-differentiated thyroid cancer) and who do not have signs of thyroid cancer which has spread to other parts of the body.
Important Safety Information
When Thyrogen is used to help detect thyroid cancer, there is still a chance all—or parts of—your cancer could be missed. In clinical studies, the most common side effects reported were upset stomach, headache, tiredness, throwing up, dizziness, prickling and tingling sensation, weakness, difficulty sleeping, and diarrhea. View additional Important Safety Information Thyrogen Full Prescribing Information
Thyroid Cancer’s Connection to Hypothyroidism
If you or someone you know has just been diagnosed with thyroid cancer, you are not alone. The American Cancer Society estimates that over 44,000 new cases of thyroid cancer are diagnosed each year. Although receiving a diagnosis of thyroid cancer can be frightening, the good news is that most forms of thyroid cancer have a very high treatment success rate, especially when found and treated early. The five year survival rate for thyroid cancer is over 97%.1 This resource center will provide you with information regarding thyroid cancer and hypothyroidism during thyroid cancer treatment.
Role of the Thyroid
Your thyroid is part of a complex communication system. Your hypothalamus, pituitary and thyroid constantly exchange information and control hormones necessary to regulate and maintain your body’s metabolism.
Normal Production of Thyroid Hormones
Watch it at Work
* The hypothalamus releases Thyrotropin Releasing Hormone (TRH)
* TRH stimulates the pituitary gland to release Thyroid Stimulating Hormone (TSH)
* TSH acts on the thyroid to take in iodine and produce thyroid hormones T3 and T4, which then circulate through the blood to all organs. TSH is the messenger that tells the thyroid gland to increase or decrease thyroid production.
* If your thyroid hormone is low, the pituitary gland releases TSH. TSH sends a signal to your thyroid gland to make more thyroid hormone.
* If your thyroid hormone is high, the pituitary gland decreases TSH production.
What is thyroid cancer?
Thyroid cancer is a malignant growth or tumor in the thyroid gland. Thyroid cancer occurs in both men and women and can occur at any age. Not all thyroid cancers are the same. There are four main types of thyroid cancer:
* Papillary
* Follicular
* Medullary
* Anaplastic
Papillary and follicular cancers, often referred to as “well-differentiated” thyroid cancers (WDTC), are the most common.
The prognosis for any given thyroid cancer patient depends on several factors, including the type of thyroid cancer, whether the disease has spread to other parts of the body, and the patient’s age at diagnosis. Early and aggressive treatment as well as commitment to long-term monitoring is essential to achieve the best outcome.
Thyroid Cancer Treatment Pathway
thyrogen_usual_pathway.gif
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The first step in the treatment process for well-differentiated thyroid cancer (WDTC) is surgery to remove the thyroid gland. This is called a thyroidectomy.
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Following surgery, your surgeon or endocrinologist will usually prescribe thyroid hormone replacement therapy. This will replace the hormone your thyroid gland was producing prior to its removal. There is no more thyroid gland to receive the TSH signal sent by the pituitary gland to stimulate the thyroid. Patients must be placed on thyroid hormone replacement therapy for life in order to satisfy the body’s thyroid hormone requirements.
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A low-iodine diet may be instituted. Your doctor may ask you to avoid certain foods and medicines that contain iodine for a few weeks before your ablation procedure or whole body scan (WBS).
*Radioiodine may be used to destroy any remaining thyroid tissue that the surgeon was not able to remove during the thyroidectomy. This is called thyroid remnant ablation.
*Long-term monitoring is important for the rest of your life, particularly in the first 5 to 10 years after surgery when the risk of your cancer returning is the highest.
What is hypothyroidism?
Hypothyroidism occurs when a person’s thyroid gland is underactive and not producing enough thyroid hormone. In thyroid cancer patients, hypothyroidism occurs after the thyroid gland has been removed or when you stop taking your thyroid hormone replacement therapy. Some people may experience only minor symptoms, but some may experience more severe symptoms.
Symptoms of hypothyroidism may include the following:
* Depression
* Weight Gain
* Difficulty concentrating
* Tiredness
* Forgetfulness
* Constipation
* Cold Intolerance
* Dry Skin and Hair
* Puffy face and eyes
* Worsening of cardiovascular conditions
* Menstrual irregularities
* Difficulty walking
* Difficulty driving vehicles and operation machinery
Important Safety Information for Thyrogen® (thyrotropin alfa for injection):
* When Thyrogen is used to help detect thyroid cancer, there is still a chance all—or parts of—your cancer could be missed.
* In a study of people being prepared for treatment with a form of iodine after thyroid surgery, results were similar between those who received Thyrogen and those who stopped taking their thyroid hormone. Researchers do not know if results would be similar over a longer period of time.
* Your doctor may take extra steps to care for you during Thyrogen treatment if you have heart disease and large amounts of remaining thyroid tissue after surgery.
* If you are over 65-years-old and did not have your entire thyroid removed during treatment of your cancer, you may be at risk for abnormal heartbeat while receiving Thyrogen. Because of this, you and your doctor will need to carefully consider the risks and benefits of Thyrogen before starting it.
* In clinical studies, the most common side effects reported were upset stomach, headache, tiredness, throwing up, dizziness, prickling and tingling sensation, weakness, difficulty sleeping, and diarrhea.
* Thyroid Cancer Overview
* Anaplastic Thyroid Cancer
* Follicular Thyroid Cancer
* Medullary Thyroid Cancer
* Hurthle Cell Thyroid Cancer
* Papillary Thyroid Cancer
Symptoms of thyroid cancer
Occasionally, symptoms such as hoarseness, neck pain, and enlarged lymph nodes do occur in people with thyroid cancer. Although as much as 75% of the population will have thyroid nodules, the vast majority are benign. Young people usually don't have thyroid nodules, but as people age, they likely develop a nodule. By the time we are 80, 90% of us will have at least one nodule.
Far less than 1% of all thyroid nodules are malignant. A nodule that is cold on scan (shown in photo outlined in red and yellow) is more likely to be malignant. Nevertheless, the majority of these are benign as well. You can read more information about thyroid nodules and their potential to be malignant below:
Introduction to Thyroid Nodules
Basic Facts about Thyroid Nodules
Simply put, thyroid nodules are lumps that commonly arise within an otherwise normal thyroid gland. Often these abnormal growths of thyroid tissue are located at the edge of the thyroid gland, so they can be felt as a lump in the throat. When they are large or when they occur in very thin individuals, they can even sometimes be seen as a lump in the front of the neck. The following is a list of facts regarding thyroid nodules:
* One in 12 to 15 young women has a thyroid nodule.
* One in 40 young men has a thyroid nodule.
* More than 95% of all thyroid nodules are benign (non-cancerous growths).
* Some are actually cysts, which are filled with fluid rather than thyroid tissue.
* Most people will develop a thyroid nodule by the time they are 50 years old.
* The incidence of thyroid nodules increases with age.
o 50% of 50 year olds will have at least one thyroid nodule.
o 60% of 60 year olds will have at least one thyroid nodule.
o 70% of 70 year olds will have at least one thyroid nodule.
Three Questions about Thyroid Nodules
1. Is the nodule one of the few that are cancerous?
2. Is the nodule causing trouble by pressing on other structures in the neck?
3. Is the nodule making too much thyroid hormone?
After an appropriate work-up, most thyroid nodules will yield an answer of no to all of the above questions. In this most common situation, there is a small- to moderate-sized nodule that is simply an overgrowth of normal thyroid tissue, or even a sign that there is too little hormone being produced.
Patients with a diffusely enlarged thyroid (called a goiter) will have what is perceived at first to be a nodule but is later found to be only one of many benign enlarged growths within the thyroid (a goiter).
Usually a fine needle aspiration biopsy (FNA) will tell if the nodule is cancerous or benign. This one test can get right to the bottom of the issue. Often an ultrasound is necessary to determine the characteristics of a thyroid nodule.
If any of the above questions are answered yes, then medical or surgical treatment is required.
Symptoms of Thyroid Nodules
Most thyroid nodules cause no symptoms at all. They are usually found by patients who feel a lump in their throat or see it in the mirror. Occasionally, a family member or friend will notice a strange lump in the neck of someone with a thyroid nodule. Another common way in which thyroid nodules are found is during a routine examination by a physician.
Occasionally, nodules may cause pain, and even rarer still are those patients who complain of difficulty swallowing when a nodule is large enough and positioned in such a way that it impedes the normal passage of food through the esophagus (which lies behind the trachea and thyroid).
Sometimes, a thyroid nodule is found because the patient is undergoing a CT scan, MRI scan, or ultrasound scan of the neck for some other reason (such as parathyroid disease, carotid artery disease, or cervical spine pain). Thyroid nodules found this way (by accident) are cancerous far less than 1% of the time.
What to Do if You Have a Nodule
Remember that the vast majority of thyroid nodules are benign. The nodule should be evaluated by a physician who is comfortable with this problem. Endocrinologists and endocrine surgeons deal with these problems on a regular basis, but many family practice physicians, general internists, and general surgeons are also adept at addressing thyroid nodules. This is covered in more detail on our nodule exam/biopsy page.
One of the first things a physician should do is ask a number of important questions regarding your health and potential thyroid problems. These questions include whether you have been exposed to nuclear radiation or received radiation treatments as a child or teenager.
What about Radiation Exposure?
Ionizing radiation has been known for a number of years to be associated with a small increased risk of developing thyroid cancer. The risk is very small and the amount of radiation exposure is usually quite high. There is typically a delay of 20 years or more between radiation exposure and the development of thyroid cancer.
Radiation was used occasionally between the 1920s and 1950s to treat certain neck infections, such as recurrent tonsillitis and certain skin conditions (such as severe acne).
In July 1997, the US government announced the results of a scientific study to determine if nuclear weapons testing in the southeast US from 1945 through the 1970s would have an effect on the development of thyroid cancer in Americans. This epidemiological study determined that these nuclear tests would likely increase the amount of thyroid cancers seen in Americans over the next several decades. The risks are substantially greater for those patients living nearby the test sites for many years. If there is any good news to this report, it is that these cancers will typically be of the well-differentiated type that have an excellent prognosis. The vast majority of these can be cured. There is no evidence that children are at increased risk of developing thyroid cancer; the small increase risk appears to be limited to those who were directly exposed in the past. Despite these increased risks, thyroid cancer is still relatively uncommon and usually very curable.
The Workup of Thyroid Nodules and the Role of Fine Needle Aspiration Biopsy (FNA)
Solitary dominant nodule of right thyroid lobeThyroid nodules increase with age and are present in almost 10% of the adult population. Autopsy studies reveal the presence of thyroid nodules in 50% of the population, so they are fairly common. 95% of solitary thyroid nodules are benign, and therefore, only 5% of thyroid nodules are malignant.
Common types of the benign thyroid nodules are adenomas (overgrowths of normal thyroid tissue), thyroid cysts, and Hashimoto's thyroiditis.
Uncommon types of benign thyroid nodules are due to subacute thyroiditis, painless thyroiditis, unilateral lobe agenesis, or Riedel's struma. As noted on previous pages, those few nodules that are cancerous are usually due to the most common types of thyroid cancers that are the differentiated thyroid cancers. Papillary carcinoma accounts for 60%, follicular carcinoma accounts for 12%, and the follicular variant of papillary carcinoma accounts for 6%. These well differentiated thyroid cancers are usually curable, but they must be found first. Fine needle biopsy is a safe, effective, and easy way to determine if a nodule is cancerous.
Thyroid cancers typically present as a dominant solitary nodule that can be felt by the patient or even seen as a lump in the neck by his/her family and friends. This is illustrated in the picture above.
As pointed out on our page introducing thyroid nodules, we must differentiate benign nodules from cancerous solitary thyroid nodules. While history, examination by a physician, laboratory tests, ultrasound, and thyroid scans (shown in the image on the right) can all provide Solitary cold nodule of thyroidinformation regarding a solitary thyroid nodule, the only test that can differentiate benign from cancerous thyroid nodules is a biopsy (the term biopsy means to obtain a sample of the tissue and examine it under the microscope to see if the cells have taken on the characteristics of cancer cells).
Thyroid cancer is no different in this situation from all other tissues of the body; the only way to see if something is cancerous is to biopsy it. However, thyroid tissues are easily accessible to needles, so rather than operating to remove a chunk of tissue with a knife, we can stick a very small needle into it and remove cells for microscopic examination. This method of biopsy is called a fine needle aspiration biopsy (FNA).
What is a Cold or Hot Nodule?
Nodules detected by thyroid scans are classified as cold, hot, or warm. Thyroid cells absorb iodine so they can make thyroid hormone out of it. When radioactive iodine is given, a butterfly image will be obtained on x-ray film showing the outline of the thyroid. If a nodule is composed of cells that do not make thyroid hormone (don't absorb iodine), then it will appear "cold" on the x-ray film. A nodule that is producing too much hormone will show up darker and is called "hot."
85% of thyroid nodules are cold, 10% are warm, and 5% are hot. Remember that 85% of cold nodules are benign, 90% of warm nodules are benign, and 95% of hot nodules are benign.
Although thyroid scanning can give a probability that a nodule is benign or malignant, it cannot truly differentiate benign or malignant nodules and usually should not be used as the only basis for recommending treatment of the nodule, including thyroid surgery.
The evaluation of a solitary thyroid nodule should always include history and examination by a physician. Certain aspects of the history and physical exam will suggest a benign or malignant condition. Remember, a biopsy of some sort is the only way to tell for sure.
The Following Features Favor a Benign Thyroid Nodule:
* Family history of Hashimoto's thyroiditis
* Family history of benign thyroid nodule or goiter
* Symptoms of hyperthyroidism or hypothyroidism
* Pain or tenderness associated with a nodule
* A soft, smooth, mobile nodule
* Multi-nodular goiter without a predominant nodule (lots of nodules, not one main nodule)
* "Warm" nodule on thyroid scan (produces normal amount of hormone)
* Simple cyst on an ultrasound
The Following Features Increase the Suspicion of a Malignant Nodule:
* Age less than 20
* Age greater than 70
* Male gender
* New onset of swallowing difficulties
* New onset of hoarseness
* History of external neck irradiation during childhood
* Firm, irregular, and fixed nodule
* Presence of cervical lymphadenopathy (swollen, hard lymph nodes in the neck)
* Previous history of thyroid cancer
* Nodule that is "cold" on scan (shown in picture above, meaning the nodule does not make hormone)
* Solid or complex on an ultrasound
Thyroid hormone levels are usually normal in the presence of a nodule, and normal thyroid hormone levels do not differentiate benign from cancerous nodules. However, the presence of hyperthyroidism or hypothyroidism favors a benign nodule (that's why a "warm" or a "hot" nodule favors a benign condition).
Thyroglobulin levels are useful tumor markers once the diagnosis of malignancy has been made, but they are non-specific in regard to differentiating a benign from a cancerous thyroid nodule.
Ultrasound accurately determines thyroid gland volume, number, and size of nodules, separates thyroid from nonthyroidal masses, helps guide fine needle biopsy when necessary, and can identify solid nodules as small as 3mm and cystic nodules as small as 2mm.
Although several ultrasound features favor the presence of a benign nodule, and other ultrasound features favor the presence of a cancerous nodule, ultrasound alone cannot differentiate benign from malignant nodules. This is covered more completely on our nodule/ultrasound page. And since 15% of cystic thyroid nodules are malignant, ultrasound determination that a nodule is cystic does not rule out thyroid cancer.
Thyroid fine needle aspiration (FNA) biopsy is the only non-surgical method that can differentiate malignant and benign nodules in most, but not all, cases. The needle is placed into the nodule several times and cells are aspirated into a syringe. The cells are placed on a microscope slide, stained, and examined by a pathologist. The nodule is then classified as non-diagnostic, benign, suspicious, or malignant.
* Non-diagnostic indicates that there are an insufficient number of thyroid cells in the aspirate and no diagnosis is possible. A non-diagnostic aspirate should be repeated, as a diagnostic aspirate will be obtained approximately 50% of the time when the aspirate is repeated. Overall, 5 to 10% of biopsies are non-diagnostic, and the patient should then undergo either an ultrasound or a thyroid scan for further evaluation.
* Benign thyroid aspirations are the most common (as we would suspect since most nodules are benign) and consist of benign follicular epithelium with a variable amount of thyroid hormone protein (colloid).
* Malignant thyroid aspirations can diagnose the following thyroid cancer types: papillary, follicular variant of papillary, medullary, anaplastic, thyroid lymphoma, and metastases to the thyroid. Follicular carcinoma and Hurthle cell carcinoma cannot be diagnosed by FNA biopsy. This is an important point. Since benign follicular adenomas cannot be differentiated from follicular cancer (~12% of all thyroid cancers) these patients often end up needing a formal surgical biopsy, which usually entails removal of the thyroid lobe that harbors the nodule.
* Suspicious cytologies make up approximately 10% of FNAs. The thyroid cells on these aspirates are neither clearly benign nor malignant. 25% of suspicious lesions are found to be malignant when these patients undergo thyroid surgery. These are usually follicular or Hurthle cell cancers. Therefore, surgery is recommended for the treatment of thyroid nodules from which a suspicious aspiration has been obtained.
FNA is the first, and in the vast majority of cases, the only test required for the evaluation of a solitary thyroid nodule. (A TSH value should also be obtained to evaluate thyroid function.) Thyroid ultrasound and thyroid scans are usually not required for evaluation of a solitary thyroid nodule. FNA has reduced the cost for evaluation and treatment of thyroid nodules and has improved yield of cancer found at thyroid surgery. Although a solitary thyroid nodule can enlarge or shrink over time, the natural history of solitary nodules reveals that most nodules change little with time.
Can I Make the Nodule Go Away by Taking Thyroid Hormone?
Several studies reveal that suppression with thyroid hormone does not decrease the size of thyroid nodules. Therefore, unless a nodule is growing or becoming symptomatic, it is not necessary to suppress the nodule. In addition, suppression of a thyroid nodule would require long-term thyroid-stimulating hormone (TSH) suppression, potentially increasing the risk of osteoporosis in these patients.
While there has been a traditional distinction between thyroid glands with a solitary nodule and multi-nodular goiters, it has been shown that approximately 50% of patients with a solitary nodule on exam will have additional nodules on thyroid ultrasound. Therefore, the differentiation between solitary nodules and multinodular goiters is becoming less clear-cut.
It has also been believed for many years that the presence of a multinodular goiter reduces the likelihood that a thyroid cancer is present, yet recent studies indicate that there might be an equal likelihood for developing thyroid cancer in a multinodular goiter just as in a solitary thyroid nodule. If a multinodular goiter has a predominant nodule, the predominant nodule should be biopsied.
In conclusion, FNA of the thyroid is a safe, inexpensive, and effective way to distinguish a benign from a malignant nodule and usually should be the first diagnostic test performed.
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The Role of Thyroid Ultrasound and What It Means
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Once a thyroid nodule has been detected (or suspected), there are a few things that the physician will want to know before any recommendations can be made regarding treatment. Remember, the vast majority of thyroid nodules are benign and nothing to worry about, so the focus is on determining which ones have any reasonable chance of being cancerous. It is those few worrisome nodules that will need to be operated upon with that portion of the thyroid removed.
One of the first tests that is routinely performed is the fine needle aspiration biopsy. The FNA will usually (but not always) tell if a nodule is benign or malignant. This is often the only test needed.
Another common test is the ultrasound. This simple test uses sound waves to image the thyroid. The sound waves are emitted from a small hand-held transducer that is passed over the thyroid. A lubricant jelly is placed on the skin so that the sound waves transmit more easily through the skin and into the thyroid and surrounding structures. This test is quick, accurate, cheap, painless, and completely safe. It usually takes only about 10 minutes and the results can be known almost immediately. Not all nodules need this test, but it is almost routine.
Ultrasound Characteristics That Suggest a Benign Nodule
* Sharp edges are seen all around the nodule
* Nodule filled with fluid and not live tissue (a cyst)
* Lots of nodules throughout the thyroid (almost always a benign multi-nodular goiter)
* No blood flowing through it (not live tissue, likely a cyst)
* More on this topic on our FNA page
Thyroid nodule with excess blood flowTo illustrate some of these points, the picture on the right shows the same ultrasound as above, but this time the probe is programmed to detect blood flow. You can now clearly see that this nodule is complex, which means that some of it is cystic, while other parts are comprised of live tissues that have a good blood supply. If this were a simple cyst filled with serous fluid, then it would have no red (artery) or blue (vein) blood flow.
This patient had no other nodules in her thyroid, so this was diagnosed as a "dominant complex nodule of the right thyroid lobe."
Since this nodule does have a few worrisome characteristics, a fine needle aspirate biopsy (FNA) was performed. In this test, a very small needle is passed into the nodule and some cells are aspirated out and then placed on a glass slide for a pathologist to stain and determine if they are malignant.
This test is very simple; it takes less than 30 seconds, is virtually pain free, and can be very accurate. If it is read as cancer, this test is almost always right.
Sometimes, however, there are not enough cells removed or some, but not all, cells look abnormal. In this case, the pathologist will not be able to tell cancer from a benign nodule. This situation usually dictates that the test be repeated or that the patient undergo surgical removal of this part of the thyroid. Remember, the vast majority of nodules are benign, and even if it is cancer, most thyroid cancers are extremely curable.
This patient had two indeterminate FNAs performed. Both needle biopsies had good tissue specimens, but the pathologist could not distinguish benign from cancer. She subsequently underwent a simple right thyroid lobectomy, and the final diagnosis was a benign follicular adenoma. She did fine after the operation and has enough normal thyroid still in her neck, so she does not have to take thyroid hormone pills
Thyroid Cancer Type and Incidence
* Papillary and/or mixed papillary/follicular
* Follicular
* Medullary
* Anaplastic
Note: Chief Justice William Rehnquist had anaplastic thyroid cancer. After reading this overview page on thyroid cancer, click here to read more about Chief Justice William Rehnquist and his classic battle with the worst kind of thyroid cancer.
What's the Prognosis?
Most thyroid cancers are very curable. In fact, the most common types of thyroid cancer (papillary and follicular) are the most curable. In younger patients, both papillary and follicular cancers have a more than 97% cure rate if treated appropriately. Both papillary and follicular cancers are typically treated with complete removal of the lobe of the thyroid that harbors the cancer, in addition to the removal of most or all of the other side.
The bottom line is that most thyroid cancers are papillary thyroid cancer, and this is one of the most curable cancers of all cancers that humans get. Treated correctly, the cure rate is extremely high.
Medullary cancer of the thyroid is significantly less common, but has a worse prognosis. Medullary cancers tend to spread to large numbers of lymph nodes very early on, and therefore require a much more aggressive operation than the more localized thyroid cancers, such as papillary and follicular. This cancer requires complete thyroid removal plus a dissection to remove the lymph nodes of the front and sides of the neck.
The least common type of thyroid cancer is anaplastic which has a very poor prognosis. Anaplastic thyroid cancer tends to be found after it has spread and is incurable in most cases. It is very uncommon to survive anaplastic thyroid cancer, as often the operation cannot remove all the tumor. These patients often require a tracheostomy during the treatment, and treatment is much more aggressive than for other types of thyroid cancer--because this cancer is much more aggressive.
What About Chemotherapy?
Thyroid cancer is unique among cancers. In fact, thyroid cells are unique among all cells of the human body. They are the only cells that have the ability to absorb iodine. Iodine is required for thyroid cells to produce thyroid hormone, so they absorb it out of the bloodstream and concentrate it inside the cell.
Most thyroid cancer cells retain this ability to absorb and concentrate iodine. This provides a perfect "chemotherapy" strategy. Radioactive Iodine is given to the patient with thyroid cancer after their cancer has been removed. If there are any normal thyroid cells or thyroid cancer cells remain in the patient's body (and any thyroid cancer cells retaining this ability to absorb iodine), then these cells will absorb and concentrate the radioactive "poisonous" iodine. Since all other cells of our bodies cannot absorb the toxic iodine, they are unharmed. The thyroid cancer cells, however, will concentrate the poison within themselves and the radioactivity destroys the cell from within. No sickness. No hair loss. No nausea. No diarrhea. No pain.
Most, but not all, patients with thyroid cancer need radioactive iodine treatments after their surgery. This is important to know. Almost all, however, should have the iodine treatment if a cure is to be expected.
Patients with medullary cancer of the thyroid usually do not need iodine therapy because medullary cancers almost never absorb the radioactive iodine. Some small papillary cancers treated with a total thyroidectomy may not need iodine therapy as well, but for a different reason.
These cancers (medullary and some small papillary cancers) are often cured with simple (complete) surgical therapy alone. This varies from patient to patient and from cancer to cancer. This decision will be made between the surgeon, the patient, and the referring endocrinologist or internist. Remember, radioactive iodine therapy is extremely safe. If you need it, take it.
Overview of Typical Thyroid Cancer Treatment
1. Thyroid cancer is usually diagnosed by sticking a needle into a thyroid nodule or removal of a worrisome thyroid nodule by a surgeon.
2. The removed thyroid nodule is looked at under a microscope by a pathologist who will then decide if the nodule is benign (95-99% of all nodules that are biopsied) or malignant (less than 1% of all nodules, and about 1-5% of nodules that are biopsied).
3. The pathologist decides the type of thyroid cancer: papillary, follicular, mixed papilofollicuar, medullary, or anaplastic.
4. The entire thyroid is surgically removed; sometimes this is done during the same operation where the biopsy takes place. He/she will assess the lymph nodes in the neck to see if they also need to be removed. In the case of anaplastic thyroid cancer, your doctor will help you decide about the possibility of a tracheostomy.
5. About 4-6 weeks after the thyroid has been removed, the patient will undergo radioactive iodine treatment. This is very simple and consists of taking a single pill in a dose that has been calculated for the patient. The patient goes home and avoids contact with other people for a couple of days (so they are not exposed to the radioactive materials).
6. A week or two after the radioactive iodine treatment the patient begins taking a thyroid hormone pill. No one can live without thyroid hormone, and if the patient doesn't have a thyroid anymore, he or she will take one pill per day for the rest of their life. This is a very common medication (examples of branded drug names include Synthroid, Levoxyl, and Armour Thyroid).
7. Every 6-12 months the patient returns to his endocrinologist for blood tests to determine if the dose of daily thyroid hormone is correct and to make sure that the thyroid tumor is not coming back. The frequency of these follow up tests will vary greatly from patient to patient. Endocrinologists are typically quite good at this and will typically be the type of doctor that follows this patient long-term.
Patient’s Guide to Thyroid Cancer and Hypothyroidism
Hypothyroidism considerations after thyroid cancer surgery
Indication
Thyrogen (thyrotropin alfa for injection) is indicated for use as an additional tool to identify thyroid disease (by testing the blood for a hormone called thyroglobulin), with or without a radiology test using a form of iodine, in the follow-up of patients with a certain type of thyroid cancer (known as well-differentiated thyroid cancer).
Thyrogen (thyrotropin alfa for injection) is also indicated for use as a preparation for treatment with a form of iodine to remove left over thyroid tissue in patients who have had surgery to take out the entire thyroid gland for a certain type of thyroid cancer (known as well-differentiated thyroid cancer) and who do not have signs of thyroid cancer which has spread to other parts of the body.
Important Safety Information
When Thyrogen is used to help detect thyroid cancer, there is still a chance all—or parts of—your cancer could be missed. In clinical studies, the most common side effects reported were upset stomach, headache, tiredness, throwing up, dizziness, prickling and tingling sensation, weakness, difficulty sleeping, and diarrhea. View additional Important Safety Information Thyrogen Full Prescribing Information
Thyroid Cancer’s Connection to Hypothyroidism
If you or someone you know has just been diagnosed with thyroid cancer, you are not alone. The American Cancer Society estimates that over 44,000 new cases of thyroid cancer are diagnosed each year. Although receiving a diagnosis of thyroid cancer can be frightening, the good news is that most forms of thyroid cancer have a very high treatment success rate, especially when found and treated early. The five year survival rate for thyroid cancer is over 97%.1 This resource center will provide you with information regarding thyroid cancer and hypothyroidism during thyroid cancer treatment.
Role of the Thyroid
Your thyroid is part of a complex communication system. Your hypothalamus, pituitary and thyroid constantly exchange information and control hormones necessary to regulate and maintain your body’s metabolism.
Normal Production of Thyroid Hormones
Watch it at Work
* The hypothalamus releases Thyrotropin Releasing Hormone (TRH)
* TRH stimulates the pituitary gland to release Thyroid Stimulating Hormone (TSH)
* TSH acts on the thyroid to take in iodine and produce thyroid hormones T3 and T4, which then circulate through the blood to all organs. TSH is the messenger that tells the thyroid gland to increase or decrease thyroid production.
* If your thyroid hormone is low, the pituitary gland releases TSH. TSH sends a signal to your thyroid gland to make more thyroid hormone.
* If your thyroid hormone is high, the pituitary gland decreases TSH production.
What is thyroid cancer?
Thyroid cancer is a malignant growth or tumor in the thyroid gland. Thyroid cancer occurs in both men and women and can occur at any age. Not all thyroid cancers are the same. There are four main types of thyroid cancer:
* Papillary
* Follicular
* Medullary
* Anaplastic
Papillary and follicular cancers, often referred to as “well-differentiated” thyroid cancers (WDTC), are the most common.
The prognosis for any given thyroid cancer patient depends on several factors, including the type of thyroid cancer, whether the disease has spread to other parts of the body, and the patient’s age at diagnosis. Early and aggressive treatment as well as commitment to long-term monitoring is essential to achieve the best outcome.
Thyroid Cancer Treatment Pathway
thyrogen_usual_pathway.gif
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The first step in the treatment process for well-differentiated thyroid cancer (WDTC) is surgery to remove the thyroid gland. This is called a thyroidectomy.
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Following surgery, your surgeon or endocrinologist will usually prescribe thyroid hormone replacement therapy. This will replace the hormone your thyroid gland was producing prior to its removal. There is no more thyroid gland to receive the TSH signal sent by the pituitary gland to stimulate the thyroid. Patients must be placed on thyroid hormone replacement therapy for life in order to satisfy the body’s thyroid hormone requirements.
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A low-iodine diet may be instituted. Your doctor may ask you to avoid certain foods and medicines that contain iodine for a few weeks before your ablation procedure or whole body scan (WBS).
*Radioiodine may be used to destroy any remaining thyroid tissue that the surgeon was not able to remove during the thyroidectomy. This is called thyroid remnant ablation.
*Long-term monitoring is important for the rest of your life, particularly in the first 5 to 10 years after surgery when the risk of your cancer returning is the highest.
What is hypothyroidism?
Hypothyroidism occurs when a person’s thyroid gland is underactive and not producing enough thyroid hormone. In thyroid cancer patients, hypothyroidism occurs after the thyroid gland has been removed or when you stop taking your thyroid hormone replacement therapy. Some people may experience only minor symptoms, but some may experience more severe symptoms.
Symptoms of hypothyroidism may include the following:
* Depression
* Weight Gain
* Difficulty concentrating
* Tiredness
* Forgetfulness
* Constipation
* Cold Intolerance
* Dry Skin and Hair
* Puffy face and eyes
* Worsening of cardiovascular conditions
* Menstrual irregularities
* Difficulty walking
* Difficulty driving vehicles and operation machinery
Important Safety Information for Thyrogen® (thyrotropin alfa for injection):
* When Thyrogen is used to help detect thyroid cancer, there is still a chance all—or parts of—your cancer could be missed.
* In a study of people being prepared for treatment with a form of iodine after thyroid surgery, results were similar between those who received Thyrogen and those who stopped taking their thyroid hormone. Researchers do not know if results would be similar over a longer period of time.
* Your doctor may take extra steps to care for you during Thyrogen treatment if you have heart disease and large amounts of remaining thyroid tissue after surgery.
* If you are over 65-years-old and did not have your entire thyroid removed during treatment of your cancer, you may be at risk for abnormal heartbeat while receiving Thyrogen. Because of this, you and your doctor will need to carefully consider the risks and benefits of Thyrogen before starting it.
* In clinical studies, the most common side effects reported were upset stomach, headache, tiredness, throwing up, dizziness, prickling and tingling sensation, weakness, difficulty sleeping, and diarrhea.
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