ABSTRACT
BACKGROUND: Brain metastases (BMs) represent the most common intracranial neoplasms in adults, affecting up to 25% of patients with metastatic cancers. Primary cancers of the lung, melanoma and colorectal are responsible for the majority of diagnosed BMs. Current therapies for BMs include stereotactic radiosurgery, whole-brain radiotherapy, surgical resection, interstitial laser thermal therapy, systemic cytotoxic chemotherapy, targeted agents, and PD1/PDL-1 blockage, which play a crucial role in cancer immunotherapy. METHODS: A systematic search was conducted through PubMed, Embase and Cochrane databases for studies that assess the benefit of neoadjuvant treatment with PD-1/PD-L1 inhibitors plus steroids and the impact of this combination on treatment effectiveness. Hazard ratios (HRs) were computed for binary endpoints, with 95% confidence intervals (CIs). We performed the meta-analysis using RStudio v4.4.2 software. RESULTS: The systematic analysis, including 1,658 patients, assessed the impact of PD-1/PD-L1 inhibitors on overall survival (OS) and progression-free survival (PFS) in treating BMs from non-small cell lung cancer (NSCLC) and melanoma. For OS, eight studies with 848 patients indicated a significant improvement using steroids (HR: 1.978; 95% CI 1.308-2.992; I2 = 62%) compared to non-users. Regarding PFS, data from four studies involving 790 patients did not reach statistical significance (HR: 1.483; 95% CI: 0.843-2.608; I2 = 82%). The addition of steroids did not show a clear beneficial effect on the efficacy of PD-1/PD-L1 inhibitors in extending progression-free survival. CONCLUSIONS: The systematic analysis underscores the effectiveness of PD-1/PD-L1 blockage in improving overall survival in patients with BMs from NSCLC and melanoma, however, their impact on delaying disease progression, especially when combined with steroids, requires further investigation to clarify their role and optimize therapeutic strategies.