Robotic CyberKnife Radiosurgery for the Treatment of Choroidal and Ciliary Body Melanoma

Abstract

To present the results of robotic assisted radiosurgery in choroidal and ciliary body melanomas treated at the Department of Ophthalmology of Ludwig-Maximilians-University and the European CyberKnife Center in Munich, Germany. Interventional case series METHODS AND MATERIALS: This retrospective study included 594 consecutive patients referred to our clinic for the treatment of choroidal and ciliary body melanomas with robotic radiosurgery (CyberKnife) from 2005 to 2019. Eye retention, local control and disease-specific survival rates were calculated as Kaplan-Meier and actuarial estimates. The impact of prescription dose, tumor size and ciliary body involvement was assessed by likelihood ratio tests and Cox regression. Among all patients that were staged according to the TNM classification system (8th edition), 22.7% were I, 57.9% II, 18.9% III and 0.5% of patients were classified as IV. Median apical tumor height and base diameter were 5.8 and 11.4 mm. The mean follow-up was 41.7 months. Local control after three and five years was 92.0% (95% CI 88.2 - 94.7%)and 84.3% (95% CI 77.9 - 89.0%) respectively for 21-22 Gy and 86.9% (95% CI 79.7 - 91.7%) and 77.7% (95% CI 68.5 - 84.6%) respectively when treated with 20 Gy or less. Eye retention was achieved in 89.9% and 81.0% after three and five years with 21-22 Gy and 85.9% and 80.0% for 20 Gy or less. Disease-specific survival rates were 93.1% (95% CI 90.2 - 95.2%) after three years, 89.8% (95% CI 86.0 - 92.6%) after five years and 87.8% (95% CI 82.8 - 91.4%) after seven years. This is the largest series of patients treated for choroidal and ciliary body melanomas with CyberKnife. Our results reflect an improvement in the outcome of CyberKnife therapy for patients suffering from choroidal and ciliary body melanoma treated with single session radiosurgery in the last decade.