Medullary Thyroid Cancer (MTC)

  • MTC accounts for less than 3% of all thyroid cancers.
  • MTC is a rare type of thyroid cancer that develops in the parafollicular C-cells of the thyroid gland.
  • These C-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.
  • MTC is easier to treat and control if found before it spreads to other parts of the body.
  • There are two types of MTC: sporadic and familial. When the disease is familial, it may be associated with hypercalcemia and adrenal tumors (i.e., pheochromocytoma).
  • Sporadic MTC usually occurs in patients ages 20 and over.
  • Familial (inherited) MTC can appear at any time from infancy to adulthood. This type of MTC 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).
  • 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.
  • Genetic testing should be done for all people diagnosed with MTC. Genetic testing is considered the standard of care and is not a research test. If it is determined that the patient has familial MTC, the immediate family members should be tested to determine whether there are genetic factors that can predict the development of MTC. The testing focuses on the RET proto-oncogene.
  • In individuals with these genetic changes, including infants and children, removal of the thyroid gland before cancer has the chance to develop has a very high probability of being a preventive cure.
  • Nearly 100% of patients who are found to have a mutation (an abnormal sequence in the RET protooncogene) will eventually develop MTC. The specific mutation can be used to determine when the thyroid gland should be removed.
  • MTC usually makes calcitonin and carcinoembryonic antigen (CEA), which can be measured by blood tests. Since each person’s body expresses these two substances a bit differently and they vary due to many variables, the absolute number is not as important as the trend over months and years.
  • MTC does not have the ability to absorb iodine. Because of this, radioactive iodine treatment should not be used to treat MTC.
  • The treatment for MTC is surgical and the long-term prognosis is not quite as positive as for differentiated thyroid cancer.
  • New medicines have been tested in clinical trials and show promise for treating medullary thyroid cancer that is progressing.

mtc
dots-pattern
dots-pattern

Overview

The purpose of this site is to provide a centralized source of current information about medullary thyroid carcinoma (MTC) for patients and their families.

Most of the contributors to this site are MTC patients or “Meddies.” We hope that our shared experiences and knowledge from years, sometimes decades, of living with MTC will be helpful and encouraging to anyone looking for answers and support. Many of us participate in an international e-mail support group for people with MTC and MEN2.

Because of the rare nature of this disease, it is natural to feel a sense of urgency and a fear of the unknown, especially when we are first diagnosed. When we meet another meddie, whether on-line or at one of the outstanding ThyCa conferences or workshops, we experience an instant kinship. The cascade of questions and information exchange that follows creates a very special bond. We hope that everyone visiting this site and the MTC e-mail group will experience this bond as we learn from and support one another.

  • If you or someone in your family is coping with MTC, we invite you to join the private Facebook group named Medullary Thyroid Cancer-MTC
  • If you would like to speak with someone who has MTC, we encourage you to contact ThyCa’s Person-To-Person Network. Or you may call the ThyCa toll-free number at 1-877-588-7904.

All too often MTC patients and their families start their MTC journey with little or no knowledge of this rare disease. By reading this web site and communicating with this worldwide group, we can have more confidence that we are staying informed and, hopefully, one step ahead of our disease.

Even though MTC is rare and we are labeled as having an “orphan” disease, we are still very much a part of the greater medical community. The intriguing science and research surrounding MTC overlaps and contributes to the knowledge and understanding of other cancers as well. We hope this MTC site encourages others by helping them appreciate that MTC is not just a footnote in a medical text book, but an actively researched disease.

If you would like to suggest additions to this website, please email to publications@thyca.org.

Disclaimer

The information on this site is compiled by and for MTC patients and their families. While the medical information is reviewed and edited by physician specialists, it is intended for educational purposes only. It should not be interpreted as medical advice or directions. Persons reviewing this information are advised to consult their own health care professionals for any matters related to their medical care.

 

Last updated: January 17, 2025