Radiosurgery alone for 1-3 newly-diagnosed brain metastases from melanoma: Impact of dose on treatment outcomes

Background/Aim: To compare different doses of stereotactic radiosurgery (SRS) for 1-3 newly-diagnosed cerebral metastases from melanoma. Patients and Methods: Fifty-four patients were assigned to dose groups of 20 Gy (N=36) and 21-22.5 Gy (N=18). Variables additionally analyzed were age, gender, Karnofsky Performance Score (KPS), lactate dehydrogenase (LDH) before SRS, number of cerebral lesions, extracranial lesions, time from melanoma diagnosis to SRS. Results: The 12-month local control was 72% after 20 Gy and 100% after 21-22.5 Gy (p=0.020). Freedom from new cerebral metastases (p=0.13) and survival (p=0.13) showed no association with SRS dose. On multivariate analyses, improved local control showed significant associations with SRS doses of 21-22.5 Gy (p=0.007) and normal lactate dehydrogenase levels (p=0.018). Improved survival was associated with normal LDH levels (p=0.006) and KPS 90-100 (p=0.046). Conclusion: SRS doses of 21-22.5 Gy resulted in better local control than 20 Gy. Freedom from new brain metastases and survival were not significantly different.