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

Abstract

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. 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. 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. 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.