Clinical characteristics and postoperative complications as predictors of radiation toxicity after treatment with I125 Eye Plaque Brachytherapy for Uveal Melanomas

Purpose: I¹²⁵ Eye Plaque brachytherapy is the standard treatment for medium-sized uveal melanomas (UM). Patients develop radiation toxicities (RTT), including radiation maculopathy (RM), radiation neovascular glaucoma/iris neovascularization (RNGI) and radiation optic neuropathy (RON). We aim to investigate demographics, pretreatment tumor characteristics and posttreatment complications as predictors of RTT. METHODS AND MATERIALS: An IRB-approved single-institution retrospective chart review was performed from 2011 to 2019 for patients with posterior UM treated with brachytherapy. We collected demographics, pretreatment tumor characteristics and posttreatment complications. Univariate analysis (UVA) and multivariate analysis (MVA) were performed using logistic regression model. Hazard ratios (HR) and corresponding p-values were reported. All tests were two-sided; statistical significance was considered when p<0.05. Results: Two hundred and fifty eight patients were evaluated. Median follow-up was 33.50 months (range 3.02–97.31). 178 patients (69.0%) had RTT. 131 patients (50.8%) developed RM. Fifty-six patients (21.7%) developed RON. Nineteen patients (7.4%) developed RNGI. UVA found shorter distance to fovea (DF) (p = 0.04), posttreatment exudative retinal detachment (PERD) (p = 0.001) and posttreatment vitreous hemorrhage (PVH) (p = 0.001) are associated with RTT. MVA found shorter DF (HR=1.03, p = 0.04), PERD (HR=2.52, p = 0.01) and PVH (HR=3.34, p = 0.006) are associated with RTT. MVA found female sex (HR=1.731, p = 0.031) and tumor height (HR=1.13, p = 0.013) are associated with RM and pretreatment retinal detachment (HR=3.41, p<0.001) is associated with RON. Conclusions: Shorter DF, PERD and PVH are associated with RTT; female sex and tumor height are associated with RM and tumor height is associated with RON. These findings serve as prognostic tools to counsel patients and promote early intervention in management of RTT.