Plaque Radiotherapy for Posterior Uveal Melanoma (PUM) in 4000 Eyes: Risk Factors for ≥15-Letter Visual Acuity Loss in the Pre-Anti-VEGF Era

Purpose: To evaluate clinical factors that lead to ≥15-letter visual acuity loss following plaque radiotherapy of posterior uveal melanoma (PUM) in the pre-anti-vascular endothelial growth factor (anti-VEGF) era. Methods: We reviewed data on 4000 consecutive patients with plaque-irradiated PUM managed between May 1976 and November 2008 to identify parameters predictive of ≥15-letter vision loss. Results: Data included median patient age (60 years), diabetes mellitus (11%), median tumor diameter (11.0 mm) and thickness (4.5 mm), and median distance to optic disc (4.0 mm) and foveola (3.0 mm). Kaplan-Meier analyses revealed ≥15-letter loss at 1 versus (vs.) 3 vs. 5 vs. 10 years in 30% vs. 60% vs. 73% vs. 82% of patients. Multivariate analyses revealed factors predictive of ≥15-letter loss included greater tumor thickness ( p <0.01, hazard ratio [HR] 1.14), shorter distance to foveola ( p <0.01, HR 0.93), greater radiation dose to foveola ( p <0.01, HR 1.01) and lens ( p <0.01, HR 1.01), and presence of diabetes mellitus ( p <0.01, HR 1.11). For small PUM, multivariate risk factors included older age ( p <0.01), diabetes mellitus ( p <0.01), and shorter distance to foveola ( p <0.02); for medium PUM, risk factors included greater tumor thickness ( p <0.01), shorter distance to foveola ( p <0.01), and less (but shorter) radiation dose to foveola ( p <0.01); for large PUM, risk factors included greater tumor thickness ( p <0.01) only. Conclusions: In the pre-anti-VEGF days, following treatment of PUM with plaque radiotherapy, clinical and treatment factors predictive of ≥15-letter visual acuity loss included greater tumor thickness, shorter distance to foveola, greater radiation dose to foveola and lens, and presence of diabetes mellitus.