Combination of Immunotherapy and Brain Radiotherapy in Metastatic Melanoma: A Retrospective Analysis.

Background: Up to 40% of patients with metastatic melanoma (MM) develop brain metastases. Radiotherapy (RT) may potentiate the effects of immunotherapy (IO), even on distant sites (abscopal effect). Material and Methods: We retrospectively analyzed all our MM patients treated with IO within 6 months before/after brain RT between 2012 and 2016. Progression-free (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method and compared with those of controls treated with IO during the same period. Results: Thirty-six cases and 25 controls were identified. Among cases, 23 patients received an anti-CTLA4 agent and 13 an anti-PD1 agent. Eighteen cases were treated with stereotactic RT and 18 with whole-brain RT. Median PFS from the beginning of RT was 4 months in first-line and 2 months in second-line treatment. A third of the cases progressed at first evaluation after RT. Median OS from the beginning of RT was 7 months in first-line and 4 months in second-line treatment. Median PFS and OS of each treatment line showed a trend towards inferiority compared with those of controls. Conclusion: Synergism between RT and IO was not observed in our case series. No cases of abscopal effect were seen, and most patients underwent early systemic progression after RT. (c) 2019 S. Karger AG, Basel