Diagnosis and therapy of sporadic and familial medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy. About 75% are sporadic (sMTC) while the remaining 25% are hereditary (hMTC). The treatment of choice for both sMTC and hMTC is surgery. An adequate initial operation provides the best chance of cure. Hence, the diagnosis of MTC should be made preoperatively. In sMTC, ultrasound, ultrasound-guided fine-needle aspiration cytology and measurement of calcitonin levels (basal and after injection of calcitonin-stimulating reagents, e.g., pentagastrin) are sensitive diagnostic tools. In hMTC, identification of a germline mutation in the proto-oncogene RET is sufficient for making the diagnosis. Total thyroidectomy is recommended in all patients, sporadic and hereditary. In addition, lymphadenectomy of the cervicocentral and both cervicolateral compartments should be performed. The only indication to perform a less extensive operation may be given in young patients with hMTC. Sufficient treatment of MTC beyond local disease is still nonexistent. Future research should concentrate on this issue.