Local tumour control and patient survival after ruthenium-106 brachytherapy for small choroidal melanoma.

Aim: To report local tumour control, metastasis and survival rates of patients with small choroidal melanoma (CM) after treatment with ruthenium-106 (Ru-106) plaque brachytherapy.

Methods: Retrospective case series of 353 consecutive eyes with small CM (thickness ≤2.5 mm and largest basal diameter ≤16 mm) treated with Ru-106 brachytherapy at the London Ocular Oncology Service, between October 2004 and May 2019.

Results: The final cohort included 310 eyes and tumour recurrence was observed in 52 (17%) eyes. Ocular retention rate was 96%. Metastatic disease and tumour-related death occurred in 18 (5.8%) and 12 (3.9%) patients, respectively. Metastases were diagnosed after a median of 54 (54±35; range 3.6-118) months from initial treatment. Kaplan-Meier estimates for tumour recurrence, melanoma-related metastases and survival were 17% (95% CI 13.3% to 22.9%), 4.8% (95% CI 2.6% to 8.5%) and 98% (95% CI 94.4% to 99.1%) at 5 years and 26% (95% CI 18.3% to 35.3%), 16% (95% CI 8.7% to 27.7%) and 92% (95% CI 84.5% to 95.7%) at 10 years, respectively. On multivariable analysis, factors predictive for tumour recurrence included juxtapapillary location, larger plaque and final tumour thickness, and for metastasis exudative retinal detachment.

Conclusion: Small CMs treated with Ru-106 brachytherapy show recurrence and death rates of 17% and 2% at 5 years and 26% and 8% at 10 years. As small CMs have better prognosis than large tumours, early treatment is the key for better survival outcomes.