Local recurrence in choroidal melanomas following Robotic assisted Radiosurgery (CyberKnife)

Background: Tumor recurrence in choroidal melanoma has been associated with decreased overall survival due to metastatic spreading. To detect risk factors of local recurrence and side effects, we analyzed tumor planning and treatment parameters in patients with recurrence of choroidal melanoma after treatment with robotic-assisted radiosurgery (CyberKnife).Methods: 694 patients treated with CyberKnife between 2005 and 2019 were retrospectively reviewed. Age, gender, best-corrected visual acuity (BCVA), tumor height and diameter were recorded. Treatment planning and radiation doses were reviewed. Salvage therapy, overall survival, metastasis, and complications were recorded. Results: 74 patients showed local recurrence. Local recurrence occurred after 42.1 months post CyberKnife treatment (mean; range: 5 - 100 months). 14 out of 74 patients (18.9%) died during follow-up. Recurrence treatment included enucleation in 51 patients (68.9%) and radiosurgery in 19 patients (25.7%). Treatment planning without contrast medium MRI, radiation dose of less than 21 Gy and insufficient margin delineation were identified as risk factors incrementing local control.Discussion: Robotic assisted radiosurgery (CyberKnife) is a suitable treatment option for large choroidal melanoma up to 12mm. Patients with significantly better visual acuity received repeat Cyberknife treatment as salvage therapy and showed an eye retention rate of 81%.