OPHTHALMOLOGIC EVALUATION OF RADIATION-RELATED OPTIC NEUROPATHY FOLLOWING IMAGE GUIDED INTENSITY-MODULATED RADIATION THERAPY (IMRT) FOR NASOPHARYNGEAL CARCİNOMA (ORONIN)

Primary treatment in nasopharynx cancers is radiotherapy (RT) or chemoradiotherapy (CRT) depending on the stage of the tumor. According to the guidelines, the dose of radiotherapy for primary tumors varies between 66-70 Gy. In consideration of modern radiotherapy techniques like IMRT with systemic chemotherapy for nasopharyngeal cancer, loco-regional control has been perfect. However, the rate of late complications from treatment, many of which are irreversible, is still high. Radiation-related optic neuropathy is the late complication that optic nerves might be affected during the radiotherapy due to the close location of the nasopharynx. Incidence of this is 8.7-9% in head and neck cancer and is observed between 2-9 years after RT. Painless, irreversible, and progressive vision loss usually occurs, and the pallor of optic disc margins, retinal vein dilatation, bleeding, and neovascularization are in the ophthalmic examination. The risk of optic neuropathy increases when the tumor is in close contact with optic nerves, radiation dose, concurrent chemotherapy used, history of diabetes or hypertension.

The aim of our study is to prospectively evaluate optic neuropathy in nasopharynx cancer patients treated in our clinic.