2463 - Predictive Risk Factors for Radiation Retinopathy in Eye Brachytherapy

Purpose/Objective(s): Diabetic retinopathy is a diabetes disorder that affects human vision. This study was performed in order to evaluate the incidence of radiation retinopathy and optic neuropathy occurring after eye plaque brachytherapy for ocular melanoma.

Materials/Methods: In this study we include all patients who had been treated with eye brachytherapy for ocular melanoma between 2015 and 2018 with a minimum follow-up of 12 months. We excluded all patients who underwent reirradiation, or vitrectomy due to tumor-resection or exudative retinal detachment. We checked correlation between tumor height and D90, D99, BED_D99, doses to apex, sclera, lens, Fovea, and optic disk, respectively, since tumor height is of clinical interest.

Results: During this period, 116 patients matched the inclusion criteria, of whom 44 (37.1 %) and 29 (25.0 %) developed radiation retinopathy and optic neuropathy after a median time of 17.9 months (2.0-36 months) and 19.8 months (0.2-36 months), respectively. Mean follow-up was 17.9 months (12-36 months). Mean age was 65 years (13-94 years). Correlation analysis showed a clear relationship between tumor height and D90. Low vision was significantly correlated to the dose to optic disk. Independent risk factors for radiation retinopathy were a centrally (<5.4 mm from sensitive structures) located tumor or a thick tumor located more than 5.4 mm from sensitive structures, while those for radiation optic neuropathy comprised a short distance and applied dose to the optic disk.

Conclusion: The risk for radiation retinopathy might be higher in central ocular melanoma. Peripheral tumors might be at high risk for radiation retinopathy as tumor thickness increases. Larger sample data is needed for validation.