Is familial non-medullary thyroid carcinoma more aggressive than sporadic thyroid cancer? A multicenter series

Background. The aggressiveness of familial non-medullary thyroid cancer (FNMTC) has been a subject of debate. The purpose of the study was to determine whether FNMTC is mere aggressive than sporadic thyroid cancer. Methods. A multicenter retrospective matched-case control study of FNMTC versus sporadic non-medullary thyroid cancer was conducted. Disease-free survival (time to recurrence) for both groups was compared. Results. Forty-eight familial cases were compared with 144 age-, gender-, and stage-matched controls. Patients with FNMTC had a significantly shorter disease-free survival compared with sporadic non-medullary thyroid cancer. Patients with FNMTC who presented with evidence of distant metastasis, or who were from families with more than 2 thyroid cancer-affected members, had the worst prognosis. The available staging systems were less likely to predict the outcome in patients with FNMTC than in patients with sporadic non-medullary thyroid cancer unless one accounted for the strength of family history in the staging system. Conclusions. FNMTC is more aggressive than sporadic non-medullary thyroid cancer. The best predictors of a poor outcome in patients with FNMTC are the number of family members affected by thyroid cancer and evidence of distant metastasis.