Purpose: To emphasize the importance of genetic studies in family members and early prophylactic thyroidectomy in oncogene mutation carriers in the management of familiar medullary thyroid carcinoma.
Methods: A retrospective review of families with familiar medullary thyroid carcinoma treated at our center in the last 7 years was performed. We identified a total of 7 families who has isolated prevalences with thyroid malignancies. Forty members of the 7 families were screened for gene RET mutations. Prophylactic total thyroidectomy was performed in every RET mutation gene carriers.
Results: In all families the index case were patients with medullary thyroid carcinoma presenting at a mean age of 37.25 years (range 23-42). The RET oncogen mutation was in codon 634 in exon 11 (multiple endocrine neoplasia type 2A) in all these patients. Fourteen gene carriers were identified with a mean age of 20 years (range 7-37), eleven of whom had medullary thyroid carcinoma at the time of surgery. Five of the gene carriers were children, with a mean age of 11 years (range 7-16), four of whom had microcarcinoma and one had metastatic carcinoma at the time of surgery. After surgery no hypoparathyroidism or recurrent nerve paralysis were documented. No pediatric patient has presented with phaeochromocytoma or hypoparathyroidism to date Four of the five children have normal calcitonin levels (< 2 pg/ml) and they are free of disease. The one who presented metastatic carcinoma has recurrent disease and is awaiting surgical treatment.
Conclusions: Genetic studies of family members related to patients with familiar medullary thyroid carcinoma and RET mutations is indispensable. The RET mutation in codon 634 exon 11 was found to be the most frequent association. Prophylactic thyroidectomy is the only curative treatment and has minimal complications when performed by expert surgeons. Early thyroidectomy is recommended since distant metastatic spread can occur at early age.