Risk of Ocular Complications Following Radiation Therapy in Patients With Nasopharyngeal Carcinoma Kuen-Tze Lin, MD; Shih-Yu Lee, PhD ; Shao-Cheng Liu, MD, PhD ; Chih-Cheng Tsao, MD; Sheng-Der Hsu, MD, PhD; Wu-Chien Chien, PhD; Chi-Hsiang Chung, PhD; Wei-Kuo Chang, MD, PhD; Yuan-Wu Chen, MD, PhD ; Chun-Shu Lin, MD, PhD Objective: To examine the risk of ocular complications following radiotherapy in patients with nasopharyngeal carcinoma (NPC). Methods: We adopted 1:1 propensity score matching and identified an NPC cohort (n = 736) and a comparison cohort (n = 736) that comprised non-NPC head and neck cancer patients who received radiotherapy in the National Health Insurance Research Database from 1997 to 2010. The follow-up period was terminated upon developing ocular complications (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM]360-379) or on December 31, 2010. Results: After adjusting for the confounding factors of the study, the NPC cohort had a higher adjusted hazard ratio (HR) for developing ocular complications than the comparison cohort (adjusted HR = 2.786, 95% confidence interval [CI] = 1.805–4.112, P < 0.001). The NPC cohort was associated with a significantly higher risk of developing ocular complications compared with the comparison cohort within 12 and after 24 months of follow-up (P < 0.05). The most common associated ocular complications were optic nerve disorder and retinopathy. Conclusions: Patients with NPC might be at higher risk of developing ocular complications after radiotherapy than non- NPC head and neck cancer patients in Taiwan. Either further investigation or routine assessments by ophthalmological physi- cian is recommended. Key Words: Ocular complications, radiation therapy, nasopharyngeal carcinoma, National Health Insurance Research Database. Level of Evidence: NA Laryngoscope, 00:1–8, 2019 INTRODUCTION Most head and neck cancer patients receive radiotherapy. Due to the tumor location, cumulative radiation doses may cause harm to the eye and orbit. 1–3 Radiation protection and modern radiation therapies allow for appropriate treatment programs that minimize complications. However, many studies have pointed out the associated adverse effects that take place in the eye, including radiation-induced cataracts, 4–6 glaucoma, 7–9 and retinopathy. 10–12 Radiation-induced ocular complications are caused by different factors, including the cellular composition of the tissue, its functional reserve to withstand the evolution of clinical complications, and the nutrient-mediated changes in the integrity of the organ. Acute radiation-induced lesions may occur in the eyelid, conjunctiva, and corneal epithelium. Typical delayed radiation-induced effects on the eye include cataracts, glaucoma, and retinopathy. These ocular complications commonly develop after a latent inter- val spanning several months to years. 1,13,14 Nasopharyngeal carcinoma (NPC) is a common head and neck neoplasm with a higher incidence in Taiwan and certain areas compared to most Western countries. Current standard treatment consists primarily of radio- therapy with or without concurrent chemotherapy. 15,16 However, due to the anatomic location of NPC and the need for a curative dose for an optimal outcome, the eyes might be exposed to a high radiation dose. Moreover, this situation can become much more sophisticated in patients with locally advanced NPC involving the skull base or cavernous sinus. 17 Under such circumstances, part of the eyes may unavoidably receive a high radiation dose, pos- sibly resulting in cataracts, retinopathy, or glaucoma. However, despite great concern for ocular complications in NPC, there is a lack of population-based studies to elu- cidate the outcomes in this endemic cancer. From the Department of Radiation Oncology (K.T.L., C-C.T., C-S.L.), ; the Department of Otolaryngology–Head and Neck Surgery (S-C.L.), ; the Division of Traumatic and General Surgery, Department of Surgery (S-D.H.), ; the Department of Medical Research (W-C.C., C-H.C.), ; the Division of Gastroenterology, Department of Internal Medicine (W-K.C.), ; the Department of Oral and Maxillofacial Surgery (Y-W.C.), Tri-Service General Hospital, ; the Graduate Institute of Aerospace and Undersea Medicine (S-Y.L.), ; the School of Public Health (W-C.C., C-H.C.), ; and the School of Dentistry (Y-W.C.), National Defense Medical Center, Taipei, Taiwan. Editor’s Note: This Manuscript was accepted for publication on August 7, 2019. Financial Disclosure: Supported by Tri-Service General Hospital grants, TSGH-C108-058 (K.-T.L.) and TSGH-C108-057 (C.-S.L.). The authors have no other funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Chun-Shu Lin, MD; Department of Radia- tion Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Department of Radiation Oncology, Tri-Service General Hospital, No. 325, Chengong Rd., Sec. 2, Neihu, Taipei 114, Taiwan. E- mail: chunshulin@gmail.com DOI: 10.1002/lary.28254 Laryngoscope 00: 2019 Lin et al.: Ocular Complications Following RT in NPC 1 The Laryngoscope © 2019 The American Laryngological, Rhinological and Otological Society, Inc.