Clinical Characteristics and Outcome of Familial Nonmedullary Thyroid Cancer: A Retrospective Controlled Study

Background: Familial nonmedullary thyroid cancer (FNMTC) is a disease defined by clustering of thyroid cancers of follicular cell origin, and it is estimated to account for 5% of all thyroid cancers. Several studies found FNMTC to be more aggressive than sporadic disease, whereas others found them to have a similar course and outcome. The purpose of this study was to determine whether FNMTC is more aggressive than sporadic thyroid cancer. Methods: A retrospective controlled study of FNMTC versus sporadic nonmedullary thyroid cancers was conducted using a registry of patients with thyroid cancer. Data on disease severity at presentation, treatment modalities, and outcome were collected. Results: Sixty-seven patients with FNMTC and 375 controls with sporadic disease were included. Follow-up period was 8.6 +/- 10 years for patients with FNMTC and 8.4 +/- 9.1 years for sporadic cases. Patients with FNMTC had comparable disease severity at diagnosis as sporadic patients, underwent similar surgical and radioiodine treatments, and had similar long-term disease-free survival. Long-term outcome in families with three or more affected relatives was similar to families with only two affected relatives. Conclusions: Our results suggest that FNMTC is not more aggressive than sporadic thyroid cancer within our studied population. After a similar therapeutic strategy, FNMTC and sporadic cases had comparable prognosis, including in families with three or more affected members.