Familial medullary thyroid carcinoma (FMTC). Study of one family (treatment criteria)

Aim: The nosology of familial medullary thyroid carcinoma (FMTC) has been d escribed as a distinct pathology, genetically determined and with autosomal dominant transmission with a gene penetrance of almost 100%. The diagnosis of this morbid condition can be made if at least four members of the same family are affected by calcitonin-secreting C-cell carcinoma. Methods and Results: We report the analysis of a family in which FMTC was d iagnosed between 1993 and 1998. Of the five patients we confirmed as being affected by FMTC, we were able to perform a prophylactic thyroidectomy in o nly one case. The high possibility of lymph-node metastasis at the time of clinical diagnosis (52-75%), and the high morbidity and radio-chemo-resista nce to adjuvant therapies, indicate total thyroidectomy with central lymphn ode dissection. Conclusion: It appears that preventive lymphadenectomy does not substantial ly improve survival, while pre-clinical diagnosis is of greater importance than surgery in improving survival and preventing recurrence. Total prevent ive thyroidectomy has been recommended in all carriers of ret genetic defec ts, even in families at risk with mutations of the 618 or 620 codon, becaus e the penetrance of FMTC approaches 100%, and a 100% accordance between pre sence of the disease and gene carrier status is reported. This procedure wo uld therefore represent the only possibility of achieving a 100% cure in su bjects affected by familial medullary thyroid carcinoma. (C) 2001 Harcourt Publishers Ltd. (C) 2001 Harcourt Publishers Ltd.