Genetic Risk Factors for Radiation Vasculopathy

Purpose: The purpose of this study was to perform a genome-wide scan for polymorphisms associated with risk of vision loss from radiation complications in patients treated with proton beam irradiation for choroidal melanoma. Methods: We identified a cohort of 126 patients at high risk of radiation complications due to tumor location within 2 disc diameters of the optic nerve and/or fovea who provided a blood sample to the Massachusetts Eye and Ear Uveal Melanoma Repository. Controls (n = 76) were defined as patients with visual acuity 20/40 or better 3 years after treatment. Cases (n = 50) were selected as patients with visual acuity 20/200 or worse due to radiation damage 3 years after treatment. Genotyping of these samples was performed using the Omni 2.5 chip (Illumina, Inc.). Results: Hypertension (odds ratio [OR] = 3.749, P = 0.0009), visual acuity at diagnosis of choroidal melanoma (OR = 1.031, P = 0.002), tumor distance to fovea (OR = 0.341, P = 6.52E-05), tumor distance to optic disc (OR = 0.481, P = 5.41E-05), and height of tumor (OR = 1.704, P = 0.0069) were associated with poor vision (20/200 or worse). Individual single nucleotide polymorphism (SNP) analysis was performed controlling for the risk factors identified using stepwise regression and the first principal component. Although this analysis determined that there were 74,529 nominally significant SNPs (P < 0.05), there were no SNPs that reached genome-wide significance (P < 5E-08). The SNP reaching the highest significance level (P < 1E-04) was rs11678387, located on chromosome 2, intergenic between EPB41L5/RALB (P = 4.43E-05). Conclusions: Visual loss from radiation vasculopathy after treatment for choroidal melanoma is not only related to tumor location but may be influenced by hypertension and possibly genetic factors.