[Prophylactic thyroidectomy in RET proto-oncogen mutation]

Analysis of prophylactic thyroidectomy cases carried out in our Center in patients with RET gene mutations.

Retrospective study of 25 patients with RET proto-oncogene mutations subjected to prophylactic thyroidectomy between January 2000 and January 2016. Epidemiologic variables, surgical technique, histological results and follow-up were studied.

Our sample consists of 25 patients, 15 males and 10 females. The range of age was from 7 months to 12 years old, with a median of 5 years old. We obtained 21 cases with NEM2A, from which 19 (76%) presented 634 mutation and 2 (8%) presented 611 mutation. Four cases were NEM2B, all with 918 mutation. Microscopical findings showed microcarcinoma, in situ carcinoma or medullary thyroid carcinoma in 16 patients (64%). Eight of them showed hyperplasia (32%) and 1 presented fibrosis (4%). The presence of elevated calcitonin was correlated with histologic alterations in 7 cases (43.7%), without significant differences (χ2 0.3; p 0.6). From 16 patients with carcinoma (13 NEM2A and 3 NEM2B), 10 were 5 years old or less at the moment of the surgery. A total thyroidectomy was performed in all patients. There were no intra or post-surgical complications. During the follow-up of the patients, levels of calcitonin, calcium, parathormone, catecholamines and metanephrines were normal, except from one case.

The study of RET proto-oncogene allows the identification of patients susceptible of performing a prophylactic thyroidectomy, which have to be carried out early, in an experienced centers.