Date Published:2015 Apr 23
Importance: Little is known about the long-term risk of dying of uveal melanoma after treatment with radiotherapy. Objective: To determine the long-term risk of dying of this disease, we evaluated melanoma-related mortality rates up to 25 years after proton beam therapy in a large series of patients with uveal melanoma. Design, Setting, and Participants: In this analysis, we included 3088 patients with uveal melanoma, identified from a hospital-based cohort and treated with proton irradiation between January 1975 and December 2005. Vital status and cause of death were ascertained through active follow-up and searches of government databases (the Social Security Death Index and the National Death Index) through December 31, 2008. Cumulative rates of melanoma-related mortality were calculated using the Kaplan-Meier method. Patient and tumor characteristics of known prognostic significance for melanoma-associated death were evaluated, including patient age and tumor dimensions. Main Outcomes and Measures: The primary outcome measure was cumulative rates of melanoma-specific mortality, and secondary measures included annual melanoma-specific mortality hazard rates and cumulative all-cause mortality rates. Results: Of 1490 deceased patients, 620 (41.6%) died of ocular melanoma. In addition, 19 patients were alive, but their melanoma metastasized, by the end of the observation period (mean follow-up after diagnosis of metastasis, 5.3 years). All-cause mortality rates in this cohort were 49.0% (95% CI, 47.0-51.1) at 15 years, 58.6% (95% CI, 56.4%-60.8%) at 20 years, and 66.8% (95% CI, 64.2%-69.4%) at 25 years. Melanoma-related mortality rates were 24.6% (95% CI, 22.8-26.4) at 15 years after treatment, 25.8% (95% CI, 24.0-27.8) at 20 years after treatment, and 26.4% (95% CI, 24.5-28.5) at 25 years after treatment. The 20-year mortality rate was 8.6% (95% CI, 6.2-11.9) for younger patients (≤60 years) with small tumors (≤11 mm) and 40.1% (95% CI, 36.1-44.3) for older patients (>60 years) with large tumors (>11 mm). Conclusions and Relevance: In this large series of patients with ocular melanoma treated conservatively with proton beam irradiation, the cumulative melanoma-related mortality rates continued to increase up to 23 years after treatment. Annual rates decreased considerably (to <1%) 14 years after treatment. Information regarding the long-term risk of dying of uveal melanoma may be useful to clinicians when counseling patients.