- Medullary thyroid cancer is a rare type of thyroid cancer that comes from a group of thyroid cells that are called parafollicular C-cells.These cells are different from the cells in differentiated thyroid cancer in the sense that they do not make thyroid hormone, they are not responsive to TSH stimulation, and they make a different protein called calcitonin.
- Medullary thyroid carcinoma (MTC) accounts for 5% to 10% of all thyroid cancers. In children and adolescents, it is a very rare disease, affecting less than one child per million per year.
- There are two types of medullary thyroid cancer: sporadic and familial.
- Sporadic medullary thyroid cancer usually occurs only in patients ages 20 and over.
- In children and adolescents, MTC is almost always the familial form, meaning that it is due to a specific mutation (defect) in the DNA of the cells of the body. This mutation occurs in a gene called the RET proto-oncogene.
- Familial (inherited) medullary thyroid cancer can appear at any time from infancy to adulthood. This type of medullary thyroid cancer often comes as part of a disease called Multiple Endocrine Neoplasia type 2 (MEN2), although it can also occur by itself in familial medullary thyroid carcinoma (FMTC).
- Medullary cancer is easier to treat and control if found before it spreads to other parts of the body. Radioactive iodine does not work in MTC. Therefore, the best hope for cure is complete surgical removal of the cancer when it is found.
- Surgery to remove the thyroid gland is the treatment of choice for medullary thyroid cancer.
- Surgical removal of lymph nodes in the neck is also done in almost all patients, particularly older children and adolescents, in whom the risk of lymph node spread is very high.
- Clinical trials of new medications are also in progress to seek better treatments for patients whose medullary thyroid cancer has metastasized and cannot be cured by surgery.
- Blood tests are done to measure a hormone called calcitonin, which is produced by the cells that develop medullary thyroid cancer.
- Blood testing is also done to measure carcinoembryonic antigen (CEA), another tumor marker made by MTC.
- Neck Ultrasound. This test is increasingly used, because it is a very sensitive way to find disease in the neck.
- Blood testing for TSH. In MTC, the TSH is kept within the normal range.
- Physical Examination. Typically every 3 to 6 months for the first 2 years and then yearly if there is no recurrence of the disease.
- Other tests sometimes used:
- Chest X-Ray
- CT scan with and without contrast, and other types of imaging modalities.
Genetic Testing for Medullary Thyroid Cancer
- Genetic testing should be performed in all patients with medullary thyroid cancer to determine whether there are genetic changes in the RET proto-oncogene.
- In individuals with these genetic changes, removal of the thyroid during childhood has a high probability of being curative.
- Once a RET mutation is identified in a patient, it is recommended that all first-degree relatives be tested for the same mutation so that appropriate screening and treatment can be undertaken.
For More Information about Medullary Thyroid Cancer
Visit the Newly Diagnosed section of the web site, which has a Medullary subsection, as well as a link to ThyCa's Medullary Thyroid Cancer E-Mail Support Group. http://www.thyca.org/newly-diagnosed
Last updated: September 27, 2022