[Medullary thyroid cancer: how tumor markers and genetics determine preventive measures]

Medullary thyroid cancer (MTC) arises from parafollicular C cells secreting calcitonin. MTC occurs both as sporadic tumors and as part of specific inherited autosomal dominant syndromes in which point mutations within a discrete set of RET codons were described. Total thyroidectomy and aggressive neck dissection represents the only chance for cure in the affected patients. Therefore, all patients with thyroid nodular disease should undergo measurement of calcitonin plasma levels to allow preclinical diagnosis of the disease and early appropriate surgery ("secondary prevention"). In case of proband patient for inherited disease, all the family members should be genetically screened to detect the disease gene carriers. Patients with germline mutation would benefit either from earlier surgery at the stage of C-cell hyperplasia or microcarcinoma or prophylactic surgery (total thyroidectomy without neck dissection) (primary prevention) before the onset of any C-cells pathology. The ideal age for performance of such prophylactic surgery is determined by the genotypic features of the disease.