Work

Impact of stereotactic radiosurgery timing relative to immune checkpoint blockade administration on brain metastasis disease and radionecrosis outcomes

Year: 2025

Type: article

Abstract: Background Whether stereotactic radiosurgery (SRS) and immune checkpoint blockade (ICB) for brain metastases (BrM) have a time window for synergistic efficacy and toxicity is unclear. We examined this question in a large, contemporary cohort of patients who received concurrent SRS and ICB. Methods Patients who received SRS for intact BrM within 1 month before to 6 months after an ICB cycle at a single center from 2018 to 2023 were included if they had no prior whole-brain radiotherapy or SRS to the same BrM. Intracranial progression-free survival (icPFS), local control (LC), distant brain control (DBC), overall survival (OS), and radionecrosis were analyzed by Kaplan–Meier and log-rank methods. Cox regression was used for uni/multivariable analysis (UVA/MVA). Results A total of 419 BrM, 170 treatment episodes, and 134 patients were analyzed. In total, 43% and 40% of patients had melanoma and non-small cell lung cancer. A shorter SRS-ICB interval significantly correlated with improved icPFS, LC, and OS, but not DBC. This was true when analyzed as either a categorical or continuous factor. On MVA, SRS-ICB interval outperformed all factors including histology, ICB type, and de novo BrM status in predicting icPFS (P = .030), LC (P = .042), and OS (P = .033). In the absence of corticosteroids, pre-SRS lymphocyte counts correlated with improved LC (P = .02). Radionecrosis was not associated with SRS-ICB interval, but with BrM size and number of ICB cycles received prior to SRS. Conclusion Delivering SRS closer to ICB cycles was associated with improved icPFS, LC, and OS without affecting radionecrosis rates. This may present a therapeutic opportunity to improve BrM outcomes.

Source: Neuro-Oncology Advances

DOI: 10.1093/noajnl/vdaf130