Prophylactic Thyroidectomy in 75 Children and Adolescents with Hereditary Medullary Thyroid Carcinoma: German and Austrian Experience

Abstract. When mutations of the

RET proto-oncogene were found in 1993 to account for hereditary medullary thyroid carcinoma (MTC), surgeons obtained the opportunity to operate on patients prophylactically (i.e., at a clinically asymptomatic stage). Whether this approach is justified, and, if so, when and to which extent surgery should be performed remained to be clarified. A questionnaire was sent to all surgical departments in Germany and Austria. All of the patients who fulfilled the following criteria were enrolled: (1) preoperatively proved RET mutation; (2) age ≤ 20 years, (3) clinically asymptomatic thyroid C cell disease; and (4) TNM classification pT0–1/pNX/pN0–1/M0. Seventy-five patients were identified, and fifteen mutations were detected in six codons. Two adolescents had unilateral pheochromocytomas as part of the multiple endocrine neoplasia II (MEN-II) syndrome. No hyperparathyroidism was noted. All patients underwent total thyroidectomy, and 57 patients went on to have lymph node dissection. Parathyroid glands were removed in 34 patients and autografted in 11. Histopathology revealed MTC in 46 patients (61%, youngest 4 years); C cell hyperplasia (CCH) only was detected in the other 29 patients. Three patients had lymph node metastases (LNMs) the youngest being age 14 years. Calcitonin levels were not useful for differentiating between CCH and MTC, but in all patients with LNMs at least the stimulated calcitonin levels were assayed. After surgery, five patients (6.7%) sustained permanent hypoparathyroidism, and one patient (1.3%) had a permanent unilateral recurrent nerve palsy. All but three patients (96%) were biochemically cured. In conclusion, prophylactic total thyroidectomy can be performed safely in experienced centers. We recommend prophylactic total thyroidectomy at age 6. Cervicocentral lymph node dissection should be included when calcitonin levels are elevated or if patients are older than 10 years. Bilateral lymph node dissection should be performed if LNMs are suspected or when patients with elevated calcitonin are older than 15 years.