Early or prophylactic thyroidectomy in MEN 2/FMTC gene carriers: results in 71 thyroidectomized patients

Background: Once genetic testing accurately identifies MEN 2 gene carriers, affected children are given the opportunity to undergo thyroidectomy at th e earliest stages of the C-cell disease. Objective: To define reliable parameters by which to identify the best mome nt for thyroidectomy in patients who are carriers of the MEN 2 gene. Patients and methods: Seventy-one MEN 2/FMTC gene carriers, collected throu gh the national register of the French Calcitonin Tumours Study Group, were evaluated. All the patients included were younger than 20 years of age and underwent total thyroidectomy. Basal and pentagastrin-stimulated calcitoni n were assayed using an immunoradiometric method (sensitivity less than 2 p g/ml). Calcitonin measurement was evaluated on the basis of histopathologic al findings in surgical thyroid specimens. Results: We found C-cell hyperplasia or medullary thyroid carcinoma in all the 71 gene carriers - even for the youngest patients - and nodal metastase s were present in four cases. Calcitonin measurement (basal or pentagastrin -stimulated) detected C-cell disease preoperatively in all patients. Six of the 71 patients were not surgically cured: one had nodal metastases, one h ad an advanced staged disease and four had an incomplete nodal dissection o r had not undergone lymph node surgery. Conclusions: Determination of calcitonin forms an integral part of the mana gement of MEN 2 gene carriers. Thyroidectomy is undisputably indicated when basal calcitonin is abnormal. When basal calcitonin is undetectable, a pen tagastrin-stimulated increase in calcitonin to more than 10 pg/ml indicates an early thyroidectomy to cure the patient.