Abstract
PURPOSE: This study aimed to investigate the clinical outcomes of stereotactic body radiation therapy (SBRT) in patients with large uveal melanoma (UM). MATERIALS AND METHODS: We conducted a retrospective review of 64 consecutive patients with UM treated with CyberKnife at Yonsei Cancer Center from September 2015 to October 2021. The median radiation dose was 60 Gy (range, 48 to 64 Gy) administered in four fractions every alternate day. The local failure-free rate (LFFR), distant metastasis-free rate (DMFR), progression-free survival (PFS), and overall survival (OS) were assessed using the Kaplan-Meier method and log-rank test. Cox regression analysis was performed to analyze the predictive factors affecting survival outcomes and the factors associated with vision loss. RESULTS: The median tumor diameter and height were 11.5 mm and 8.4 mm, respectively. After a median follow-up of 32.1 months (range, 4.9 to 89.9 months), the 3-year LFFR, DMFR, PFS, and OS were 89.5%, 70.5%, 65.5%, and 89.4%, respectively. Enucleation was performed in 13 (20.3%) patients, with three cases attributed to disease progression. A larger tumor diameter was associated with significantly worse DMFR (hazard ratio [HR], 1.35; p=0.015) and OS (HR, 1.49; p=0.026) in the multivariate analysis. Regarding visual prognosis, 41 patients (64.1%) had baseline visual acuity ≥ 20/200, but only four patients (6.3%) maintained visual acuity ≥ 20/200 by the final follow-up. Initial visual acuity ≥ 20/40 (HR, 0.45; p=0.030) was the single favorable significant factor predicting visual retention ≥ 20/200 in multivariate analysis. CONCLUSION: SBRT using CyberKnife demonstrated a comparable local control rate to that observed in historical studies for patients with large UM. Distant metastasis and treatment-related ocular toxicity remain the limitations of this treatment.