Radiation-induced optic neuropathy following external beam radiation therapy for nasopharyngeal carcinoma: A retrospective case-control study.

Radiation-induced optic neuropathy (RION) is a severe ocular complication in patients with nasopharyngeal carcinoma (NPC) following external beam radiation therapy. However, the systemic risk factors for this condition remain unclear. Therefore, patients with NPC who received radiotherapy between 2004 and 2007 at the Sun Yat-Sen University Cancer Center were retrospectively reviewed in this case-control study. The study included 40 RION patients and 40 patients in the control group, who were strictly matched to the RION patients by tumor histopathology, location, Union for International Cancer Control-Tumor Node Metastasis classification and radiotherapy protocol. Univariate and multivariate statistical regression analyses were performed to identify factors predictive of RION. The univariate analysis demonstrated that age (>60 years), gender (female) and chemotherapy significantly affected the risk of RION, whereas diabetes, hypertension and hepatitis B virus infection did not exert a significant effect. The results of the multivariate analysis suggested that only gender and chemotherapy were significantly associated with an increased incidence of RION. Therefore, the results of the present study suggested that female gender and chemotherapy constitute risk factors for the development of RION following radiotherapy for NPC. The ocular symptoms of high-risk patients should be carefully investigated and reported by ophthalmologists.