[Medullary carcinoma of the thyroid: diagnosis and therapy]

Medullary thyroid carcinoma (MTC) originates in the thyroid C cells, or parafollicular cells, secreting calcitonin. It may be either sporadic or familial. Familial form can be isolated or expression of a multiple endocrine neoplasia type II. Mutations of the RET proto-oncogene have been identified in the germline DNA of patients with familial MTC syndromes. Genetic testing can identify patients affected by multiple endocrine neoplasia and familial MTC, allowing early diagnosis and possible cure. The initial treatment is surgical and the adequate surgery consists of total thyroidectomy. The treatment of occult or minimal disease can be curative. Plasma calcitonin measurements are excellent markers for post-operative follow-up. Imaging study can help to discover recurrent or metastatic disease. Adjunctive therapy includes radiotherapy and chemotherapy. Radiotherapy is reserved for bone metastases or for non resectable neck recurrences. Chemotherapy is reserved for patients with progressive MTC. Many chemotherapeutic regimens have been tried, results are controversial.