An increasing number of patients are identified in one of the three familial settings of MTC that are diagnosed using biochemical or genetic screening for RET gene mutations. Routine use of screening to diagnose MTC led to significant decreases in both the age of diagnosis and the incidence of lymph node metastases, as well as a significant increase in the number of patients cured biochemically at these earlier operations. Wells et al.56 used a molecular genetic screening technique to identify patients who are carriers of the MEN-2A mutation as infants or young children. Before any abnormality in basal or stimulated calcitonin, these patients undergo a total thyroidectomy and central neck dissection. Pathologic evaluation of these children’s thyroid glands identified C-cell hyperplasia, microscopic, or macroscopic MTC. In the initial trial, no patients treated with this strategy had evidence of lymph node metastases, and this surgical strategy should be curative.56

The genetic test for the mutations in the RET gene are commercially available, and many individuals are reporting series based on early operations for patients identified by RET mutation screening. A recent review noted that in a total of 209 patients treated in this manner, 3.4% had normal thyroid glands with no evidence of C-cell hyperplasia or MTC. It has also been noted in these patients undergoing prophylactic operations that there was an 8.6% incidence of lymph node metastases.57 Based on these results, it is thought that ...