ABOUT THYROID CANCER

  1. Overview
  2. Four Primary Types of Thyroid Cancer
  3. Thyroid Cancer Symptoms
  4. More About Medullary Thyroid Cancer
  5. Medullary Thyroid Cancer Occurs in Four Clinical Settings
  6. Management of Medullary Thyroid Cancer
  7. FDA-Approved Drugs for Medullary Thyroid Cancer
  8. FDA-Approved Drug for Differentiated Thyroid Cancer
  9. Clinical Trials for Thyroid Cancer
  10. More links about Thyroid Cancer

Thyroid cancer has been the fastest increasing cancer for a number of years. As quoted in the American Cancer Society's Cancer Statistics 2014 publication: 62,980 are predicted to be diagnosed with thyroid cancer in 2014 and states: “the largest annual increases from 2006 to 2010 were for cancers of the thyroid (5.4% and 6.5% in men and women, respectively). The 2014 prediction is a 4.5% increase compared to the 2013 number of 60,222. Previous numbers were: 2012 prediction of 56,450, 2011 prediction was 48,020; the 2010 prediction was 44,670, the 2009 estimate was 37,200, and the 2006 prediction was 30,180. Since Nikki was diagnosed in 2010, there has been a 41% increase in the totals (from 44,670 to 62,980)!

Overview

Thyroid cancer begins in the thyroid gland, which is located in the front of the neck just below the larynx (voice box). The thyroid gland is part of the endocrine system, which regulates hormones in the body. The thyroid gland absorbs iodine from the bloodstream to produce thyroid hormone, which regulates a person's metabolism.

Thyroid cancer begins when the cells in the thyroid begin to change, grow uncontrollably, and eventually form a tumor. There are two types of tumors: benign (noncancerous) and malignant (cancerous, meaning that it can spread to other parts of the body). Thyroid tumors can also be called nodules, and 90% of all thyroid nodules are benign.

A healthy thyroid gland is barely palpable (capable of being touched or felt). A normal gland has two lobes, one on each side of the windpipe, joined by a narrow strip of tissue called the isthmus. If a tumor develops in the thyroid, it is felt as a lump in the neck. A swollen or enlarged thyroid gland is called a goiter, which may be due to iodine deficiency. Most Americans receive enough iodine from salt, and a goiter under these circumstances is caused by other reasons.

The thyroid gland contains two types of cells: follicular cells, which are responsible for the production of thyroid hormone, and C cells, which make calcitonin, a hormone that participates in calcium metabolism.

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Four Primary Types of Thyroid Cancer

Papillary thyroid cancer. Papillary thyroid cancer develops from the follicular cells and grows slowly. It is usually found in one lobe; only 10% to 20% of papillary thyroid cancers appear in both lobes. Papillary thyroid cancer is a differentiated thyroid cancer, meaning that the tumor looks similar to normal thyroid tissue under a microscope.

Follicular thyroid cancer. Follicular thyroid cancer also develops from the follicular cells and usually grows slowly. Follicular thyroid cancer is also a differentiated thyroid cancer, but it is less common that papillary thyroid cancer.

These two types of cancer are very often curable, especially when found early and in people younger than 45. Together, papillary and follicular thyroid cancers make up 80% to 90% of thyroid cancers.

Medullary thyroid cancer (MTC). MTC develops in the C cells and is sometimes the result of a genetic syndrome called multiple endocrine neoplasia type 2 (MEN2). This tumor has very little, if any, similarity to normal thyroid tissue. MTC can often be controlled if it is diagnosed and treated before it spreads to other parts of the body. MTC accounts for 5% to 10% of thyroid cancers.

Anaplastic thyroid cancer. This rare and fast-growing, poorly differentiated thyroid cancer starts from differentiated thyroid cancer or a benign tumor of the gland. Anaplastic thyroid cancer can be subtyped into giant cell classifications. Because this type of cancer grows so quickly, it can be more difficult to treat successfully.

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Thyroid Cancer Symptoms

A nodule in the thyroid gland can be noticeable to the person, especially if they have done a neck check. It is common that the nodule or lump is not painful. There are certainly times where a person will not feel the nodule at all. Other symptoms can include: hoarseness, difficulty swallowing, neck pain or a cough. Please click here for more information displayed by Johns Hopkins Medicine.

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More About Medullary Thyroid Cancer

On the Bite Me Cancer website, we want to now focus a little more attention on Medullary Thyroid Cancer, since that is what Nikki has (specifically, Sporadic Medullary).

Medullary tumors are the third most common of all thyroid cancers (about 5 to 8 percent). Unlike papillary and follicular thyroid cancers which arise from thyroid hormone producing cells, medullary cancer of the thyroid originates from the parafollicular cells (also called C cells) of the thyroid. These C cells make a different hormone called calcitonin (thus their name) which has nothing to do with the control of metabolism the way thyroid hormone does. As you will see below, the production of this hormone can be measured after an operation to determine if the cancer is still present, and if it is growing. This cancer has a much lower cure rate than does the "well differentiated" thyroid cancers (papillary and follicular), but cure rates are higher than they are for anaplastic thyroid cancer.

  • Occurs in 4 clinical settings (see below), can be associated with other endocrine tumors
  • Females more common than males (except for inherited cancers)
  • Regional metastases (spread to neck lymph nodes) occurs early in the disease
  • Spread to distant organs (metastasis) occurs late and can be to the liver, bone, brain, and adrenal medulla
  • Not associated with radiation exposure
  • Usually originates in the upper central lobe of the thyroid
  • Poor prognostic factors include age > 50, male, distant spread (metastases), and when seen in patients with other endocrine tumors due to MEN II-B syndrome
  • Residual disease (following surgery) or recurrence can be detected by measuring calcitonin (a hormone that should be measured every 4 months for the first few years and then every 6 months for ever)

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Medullary Thyroid Cancer Occurs in Four Clinical Settings

  1. Sporadic- Accounts for 80% of all cases of medullary thyroid cancer. They are typically unilateral and there are no associated endocrinopathies (not associated with disease in other endocrine glands. Peak onset 40 - 60. Females outnumber males by 3:2 ratio. One third will present with intractable diarrhea. Diarrhea is caused by increased gastrointestinal secretion and hypermotility due to the hormones secreted by the tumor (calcitonin, prostaglandins, serotonin, or VIP).
  2. MEN II-A (Sipple Syndrome). Multiple Endocrine Neoplasia Syndromes (abbreviated as "MEN" and pronounced "M", "E", "N") are a group of endocrine disorders which occur together in the same patient and typically are found in families because they are inherited. "Syndromes" are medical conditions which occur in groups of three. Sipple syndrome has [1] bilateral medullary carcinoma or C cell C cel hyperplasia, [2] pheochromocytomand [3] hyperparathyroidism. This syndrome is inherited and is due to a defect of a gene (DNA) which helps control the normal growth of endocrine tissues. This inherited syndrome is passed on to all children who get the gene (inherited in an autosomal dominant fashion), which theoretically, would be 50% of all offspring of a person with this defective gene. Because of this, males and females are equally affected. Peak incidence of medullary carcinoma in these patients is in the 30's.
  3. MEN II-B. This syndrome also has [1] medullary carcinoma and [2] pheochromocytoma, but only rarely will have hyperparathyroidism. Instead these patients have [3] an unusual appearance which is characterized by mucosal ganglioneuromas (tumors in the mouth) and a Marfanoid habitus. Inheritance is autosomal dominant as in MEN II-a, or it can occur sporadically (without being inherited). MEN II-B patients usually get medullary carcinoma in their 30's, and males and females are equally effected. As with MEN II-A, pheochromocytomas must be detected prior to any operation. The idea here is to remove the pheochromocytoma first to remove the risk of severe hypertensive episodes while the thyroid or parathyroid is being operated on.
  4. Inherited medullary carcinoma without associated endocrinopathies. This form of medullary carcinoma is the least aggressive. Like other types of thyroid cancers, the peak incidence is between the ages of 40 and 50.

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Management of Medullary Thyroid Cancer

In contrast to papillary and follicular cancers, little controversy exits when discussing the management of medullary thyroid cancer. After assessment and treatment of associated endocrine conditions (such as pheochromocytomas if present) by an endocrinologist, all patients should receive total thyroidectomy, a complete central neck dissection (removal of all lymph nodes and fatty tissues in the central area of the neck), and removal of all lymph nodes and surrounding fatty tissues within the side of the neck which harbored the tumor. A diagram of thyroid operations are covered in greater detail (with drawings) on another "surgical options" page.

Although thyroid cells have the cellular mechanism to absorb iodine (see papillary cancer page), medullary thyroid cancer does not arise from this type of thyroid cell. Therefore, radioactive iodine therapy is not useful for the treatment of medullary thyroid cancer. Similarly, if medullary cancer spreads to distant sites, it cannot be found by iodine scanning the way that distant spread from papillary or follicular cancer can.

What about long-term follow up? In addition to the usual cancer follow up, patients should receive a yearly chest x-ray as well as calcitonin levels Serum calcitonin is very useful in follow up of medullary thyroid cancer because no other cells of the body make this hormone. A high serum calcitonin level that had previously been low following total thyroidectomy is indicative of recurrence. Under the best circumstances, surgery will remove all of the thyroid and all lymph nodes in the neck which harbor metastatic spread. In this case, post operative calcitonin levels will go to zero. This is often not the case, and calcitonin levels remain elevated, but less than pre-operatively. These levels should still be checked every 6 months, and when they begin to rise, a more diligent examination is in order to find the source.

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FDA-Approved Drugs for Medullary Thyroid Cancer

On April 6, 2011, the FDA approved the first chemo drug for the treatment of Medullary Thyroid Cancer. See the links below for more information:

On November 29, 2012, the FDA approved the second chemo drug for the treatment of Medullary Thryoid Cancer. See the link below for more information:

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FDA-Approved Drug for Differentiated Thyroid Cancer

On November 22, 2013, the FDA approved the drug Nexavar (Sorafenib) to treat metastatic differentiated Thyroid Cancer where radioactive iodine treatment is no longer effective.

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Clinical Trials for Thyroid Cancer

For information about current clinical research trials for thyroid cancer and other diseases, go to the following U.S. Government website: www.clinicaltrials.gov. This is the website for the U.S. Government's Clinical Trials Database. This database provides information about clinical research trials for thyroid cancer and other diseases. This list describes clinical trials that are recruiting new participants.

Searching for Clinical Trials Through NCI Cancer Centers' Web Sites

In addition to the web sites listed above, the Web sites maintained by NCI-designated Cancer Centers are supplementary resources for locating clinical trials. Here is the web site with further information and links to the NCI-designated Cancer Centers: http://www.cancer.gov/clinicaltrials/search.

Thyroid Clinical Trials Site

www.ThyroidTrials.org is the American Thyroid Association's (ATA) compendium of clinical trials for thyroid diseases, including thyroid cancer. The ATA Trial finder is a one-stop site to search multiple information sources, including public and private information sources and trials screened by experts from the American Thyroid Association.

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More links about Thyroid Cancer