Neutron radiation therapy for advanced thyroid cancers

Purpose: The aim of this study was to review institutional outcomes for advanced thyroid cancers treated with fast neutron radiation therapy (FNRT) and photon radiation therapy (RT). Methods and materials: In all, 62 consecutive patients were analyzed. Fifty-nine had stage IV disease. Twenty-three were treated with FNRT and 39 with photon RT. Median follow-up was 14 months. The primary endpoint was overall survival (OS). Results: There was no significant difference in median OS between FNRT and photon RT (26 vs 16 months; P = .49). Patients with well-differentiated histologies had superior median OS with photon RT (17 vs 69 months; P = .04). There was a nonsignificant trend toward improved OS with FNRT for medullary and anaplastic histologies. Conclusions: Outcomes in this study are in line with historical results. There is an apparent detriment in OS with FNRT for well-differentiated histologies and a trend toward improved OS with medullary and anaplastic histologies that warrants further investigation.