What are the characteristics?
Medullary thyroid cancer (MTC) accounts for 5% to 10% of all thyroid cancers. It is extremely rare in children and adolescents, with an annual incidence of less than 1 in 1 million in the United States.
MTC arises from parafollicular cells of the thyroid. These cells, unlike differentiated thyroid cancer cells, do not produce thyroid hormones and do not respond to TSH (thyrotropin, thyroid stimulating hormone), but instead produce a protein called calcitonin (CT).
MTC is classified as sporadic or familial. The former usually occurs in people over 20 years of age. The latter may occur at any age. Familial MTC is usually part of multiple endocrine neoplasia type II (MEN2) or can occur alone. MTC in children and adolescents is almost always familial, meaning that it is caused by a specific mutation (defect) in the DNA of the somatic cells. This mutation occurs in the RET gene.
How is it treated?
MTC is relatively easy to control and treat if the cancer has not metastasized to other parts of the body. Radioactive iodine (RAI, mainly iodine-131) therapy does not work for MTC, so the best treatment is complete surgical removal of the lesion.
The risk of lymph node metastasis is very high in almost all patients, especially in older children and adolescents, even if lymph node dissection is performed during surgery.
For patients who have developed metastases and cannot be cured by surgery, participation in clinical trials of new drugs may identify better treatments.
What tests are needed for follow-up?
- Blood is drawn for calcitonin and carcinoembryonic antigen (CEA). They are both produced by MTC and can be used as tumor markers.
- Neck ultrasound.
- Blood is drawn for TSH. in MTC, TSH remains within the normal range.
- Physical examination. Usually a physical exam every 3 to 6 months for the first 2 years after diagnosis, or once a year if there is no recurrence.
- Other tests include chest x-ray, CT or enhanced CT, and other imaging tests.
Who needs genetic testing?
- All patients with MTC should have genetic testing to determine if there is a mutation in the RET gene.
- Children with RET mutations who have prophylactic removal of the thyroid gland in childhood have the potential for cure.
- Once the presence of a RET mutation is identified, it is recommended that the patient’s children also undergo genetic testing to obtain early treatment.
This article is from http://www.thyca.org网站, compiled by the medical team of Tencent Medical Dictionary, and is used with permission.