Robotic CyberKnife radiosurgery for small choroidal melanomas

Abstract

Plaque brachytherapy is the most common procedure for the treatment of small choroidal melanoma, especially in posteriorly located tumors. However, there is only little information on outcome after treatment with stereotactic radiosurgery, for example, CyberKnife radiosurgery. We reviewed patients with choroidal melanoma (maximum tumor height 4 mm) treated with CyberKnife radiosurgery. Demographic information, tumor dimension, complications, metastasis and overall survival during the whole follow-up were tracked and analyzed with a specific focus on local tumor control and potential risk factors. One hundred eighty-eight patients (102 female, 54.2%) with a median age of 63 years [interquartile range (IQR): 54-73 years] were analyzed over a median of 46 months (IQR: 24-62 months). Metastasis occurred in 14 patients (7.4%) in median of 18 months after treatment (IQR: 13-47 months) and survival was achieved in 178 patients (94.7%). Within the observation period, eye retention was observed in 166 patients (88.3%). Superior local control was achieved in patients who received a prescription dose of at least 21 Gy or more (91.6%; P = 0.04). Other potential risk factors incrementing local control were treatment planning with missing MRI in advance and too small target delineation during the planning process. Radiosurgery (CyberKnife) in a single, outpatient procedure is suitable for the treatment of small choroidal melanoma. We found local control rate after 3 years compared to the standard treatment with plaque brachytherapy. On the study side, 15 years of CyberKnife treatment allowed to identify risk factors that might increment local control and thus improve treatment regimens.