Prophylactic thyroidectomy, based on direct genetic testing, in patients at risk for the multiple endocrine neoplasia type 2 syndromes.

Since the discovery that germ-line mutations in the RET protooncogene are responsible for the multiple endocrine neoplasia (MEN) syndromes types 2A and 2B, prophylactic thyroidectomy has been recommended for MEN patients to prevent medullary thyroid carcinoma (MTC). In this report, we present the medium-term follow up results on the earliest group of 18 patients having prophylactic thyroidectomy for MEN 2A. There were no operative complications. Microscopic or grossly evident MTC was present in 14 (78%) of the resected patients. None of the patients had metastasis of their MTC to regional lymph nodes. At three years' follow up, there is no evidence of residual or recurrent MTC, based on biochemical testing. We conclude that prophylactic thyroidectomy, based on direct DNA testing for RET gene mutations, is an effective and safe way to manage MTC in patients with MEN 2A.