Gamma Knife Stereotactic Radiosurgery With a Reduced Peripheral Dose: Outcomes in Uveal Melanoma Patients

Purpose: Gamma Knife stereotactic radiosurgery (GK SRS) is an established alternative option for treating uveal melanoma in appropriate candidates. Despite proven efficacy, the optimal GK SRS dose remains uncertain. This study evaluated the safety and efficacy of a reduced-dose protocol. Methods and Materials: In this retrospective study, 24 adult patients with medium- or large-sized uveal melanoma unsuitable for plaque brachytherapy underwent GK SRS, with a median peripheral dose of 24 Gy. Local failure was defined according to the Collaborative Ocular Melanoma Study criteria. Kaplan-Meier methods were used to estimate local tumor control and vision outcomes. Results: In this cohort, 50% of patients had medium-sized tumors, and 50% had large-sized tumors. Local tumor control was 100% at 1 year and 95% at 2 years. There was no statistically significant difference in local control between medium and large tumors (P = .303); notably, all confirmed failures occurred in the medium-sized tumor group. The eye preservation rate was 83.3%. Regarding visual toxicity, 69.6% of patients maintained vision above the legal blindness threshold at 1 year. Conclusion: With favorable visual preservation, the 24 Gy dose yielded local tumor control comparable to that of previously published higher-dose protocols. Further investigations are warranted to define the dose that best balances tumor control and vision preservation in uveal melanoma.