Medullary thyroid cancer: multivariate analysis of prognostic factors influencing survival.

AIMS: The aims of this study were to assess the long-term results of treatment of medullary thyroid carcinoma (MTC) and to define prognostic factors. METHODS: Retrospective analysis of all patients diagnosed with MTC between 1949 and 1998 and treated in our unit was carried out. RESULTS: One hundred and sixty-two patients (87 females, 75 males) were identified; 52 patients (32%) had familial disease. Median follow-up was 9 years (2-20 years). The majority of patients (90%) presented with a thyroid mass or enlarged neck nodes. Total/subtotal thyroidectomy was performed in 129/18 patients respectively; 45 patients also underwent neck dissection while 52 had simple nodal excision. External beam radiotherapy (RT) was given to 76 patients with advanced disease at presentation. Overall survival was 72% at 5 years and 56% at 10 years; case-specific survival was very similar. In multivariate analysis the factors which were significant predictors of survival were age at diagnosis, extent of nodal disease, extent of surgery and metastases at presentation. RT significantly reduced local relapse in patients with ipsilateral nodal disease. CONCLUSIONS: MTC may be associated with prolonged survival; the best prognosis occurs in young patients undergoing total thyroidectomy and neck dissection. External beam RT significantly reduces local relapse in patients with limited nodal disease.