Predictors of Local Recurrence and Progression-Free Survival in Iodine-125 Brachytherapy-Treated Uveal Melanomas: A Modern Institutional Study

Introduction: Iodine-125 brachytherapy is an effective eye-sparing treatment for uveal melanoma. Previous work has shown that uveal melanomas cluster into distinct molecular classes based on gene expression profiles – discriminating low-grade from high-grade tumors. Our objective was to identify clinical and molecular predictors of local recurrence (LR) and progression-free survival (PFS). Methods: We constructed a retrospective database of uveal melanoma patients from the University of Miami’s electronic medical records that were treated between January 8, 2012, and January 5, 2019, with either COMS-style or Eye Physics plaque. Data on tumor characteristics, pretreatment retinal complications, post-plaque treatments, LR, and PFS were collected. Univariate and multivariate Cox models for cumulative incidence of LR and PFS were conducted using SAS version 9.4. Results: We identified 262 patients, with a median follow-up time of 33.5 months. Nineteen patients (7.3%) had LR, and 56 patients (21.4%) were classified as PFS. We found that ocular melanocytosis (hazard ratio = 5.55, p < 0.001) had the greatest impact on PFS. Genetic expression profile did not predict LR outcomes (hazard ratio = 0.51, p = 0.297). Conclusion: These findings help physicians identify predictors for short-term brachytherapy outcomes, allowing better shared decision making with patients preoperatively when deciding between brachytherapy versus enucleation. Patients stratified to higher risk groups based on preoperative characteristics such as ocular melanocytosis should be monitored more closely. Future studies must validate these findings using a prospective cohort study.