Prognostic value of hypothyroidism in patients undergoing intensity-modulated radiation therapy for nasopharyngeal carcinoma

Background The purpose of this study was to investigate the effect of hypothyroidism and thyroxine replacement therapy on the prognosis of nasopharyngeal carcinoma (NPC) patients. Methods The clinical data of 284 NPC patients, who received intensity-modulated radiation therapy (IMRT) between January 2011 and December 2016, were retrospectively analyzed. Results Hypothyroidism occurred in 38% of patients. Patients with hypothyroidism had significantly better disease-free survival (DFS) (p = 0.002) and relapse-free survival (RFS) (p = 0.008). Multivariate analysis showed that hypothyroidism was a positive independent prognostic factor (DFS and RFS). Among the patients with hypothyroidism, thyroxine replacement therapy did not yield inferior survival (DFS, RFS, all p > 0.05). Conclusions The NPC patients with complete response are at risk of hypothyroidism, which is attributable to escalating dose. These patients experienced clinical hypothyroidism could be adequately treated with thyroid hormone replacement. Further investigation of the underlying biological mechanism and potential therapeutic implications are required.