Medullary thyroid carcinoma

This review outlines advances in the diagnosis, genetic testing, and progress in medullary thyroid cancer (MTC) treatment in light of the most recent evidence.

English-language articles pertaining to MTC published up to 2012 were reviewed. The pertinent articles and their references were obtained and those considered relevant were reviewed for inclusion.

MTC is an uncommon neuroendocrine malignancy that accounts for 5% of thyroid cancers. MTC presents in sporadic and familial forms (multiple endocrine neoplasia [MEN] 2A, MEN 2B, or familial MTC syndromes). The familial forms are secondary to germline mutations in the REarranged during Transfection (RET) proto-oncogene. Early diagnosis and treatment is paramount. Genetic testing has made possible early detection in asymptomatic carriers and high-risk patients, with early or prophylactic surgery being curative in many. All carriers of an RET mutation should be evaluated and treated surgically for MTC. The primary treatment in all patients diagnosed with MTC is total thyroidectomy with central lymph node dissection. Calcitonin and carcinoembryonic antigen levels can be used as prognostic factors and as tumor markers. If elevated, further investigation, including use of imaging modalities, may be necessary for evaluation of metastatic disease. Surgery remains the main treatment for local and locally advanced disease.

MTC is rare, but morbidity and mortality remain high if untreated. Genetic testing should be offered to all patients. Treatment of choice remains total thyroidectomy and central lymph node dissection. Palliative treatment for advanced disease includes surgery, radiation, standard chemotherapy, chemoembolization and more recently, targeted therapies (tyrosine kinase inhibitors).