What Is New in Diagnostics and Management of Medullary Thyroid Carcinoma.

Medullary thyroid carcinoma (MTC) is a rare neoplasm originating from parafollicular C cells. It secretes calcitonin (Ctn), a highly sensitive and specific tumor marker, which allows for early diagnosis and defines postoperative cure or persistence/recurrence of MTC. Germline mutations in the RET proto-oncogene are responsible for the development of MTC in MEN2. Somatic RET mutations modify the behavior of MTC and are a target for systemic therapy with selective RET inhibitors. Recent advances in preoperative immunohistochemistry and molecular diagnostics in biopsies achieved by fine needle aspiration significantly improves diagnosis and allows classification in low and high risk MTC with important implications for treatment and prognosis. This personalized approach enables a less aggressive surgery in low risk MTC patients, reduces the incidence of complications and improves quality of life. Risk stratification in MEN2 patients based on genotype-phenotype correlation of the different RET mutations allows cure by personalized thyroidectomy. Postoperative imaging in patients with persistent or recurrent MTC with PET/CT using different radiopharmaceuticals proved to be sensitive and accurate in detecting MTC recurrences/metastases and assesses their biological and clinical aggressiveness. Molecular genetic classification of tumors enables personalized systemic therapies with multikinase inhibitors or selective RET inhibitors in patients with advanced metastasized and progressive disease. Despite the recent progress in diagnosis and treatment, confirmation of these new procedures and standardization of these approaches in MTC are required.