Efficacy of PD-1 or PD-L1 Inhibitors and Central Nervous System Metastases in Advanced Cancer: A Meta-Analysis

BACKGROUND: Little is known about the efficacy of programmed cell death protein-1 (PD-1) or programmed cell death-ligand 1 (PD-L1) inhibitors in patients with central nervous system (CNS) metastases. OBJECTIVE: This study aimed to assess the difference in efficacy of PD-1 or PD-L1 inhibitors in patients with and without CNS metastases. METHODS: From inception to March 2020, PubMed and Embase were searched for randomized controlled trials (RCTs) about PD-1 or PD-L1 inhibitors. Only trails with available hazard ratios (HRs) for overall survival (OS) of patients with and without CNS metastases simultaneously would be included. Overall survival hazard ratios and their 95% confidence interval (CI) were calculated, and the efficacy difference between these two groups was assessed in the meantime. RESULTS: =0.06 P=0.80). CONCLUSION: With no significant heterogeneity observed between patients with or without CNS metastases, patients with CNS metastases should not be excluded in the PD-1 or PD-L1 blockade therapy. Future research should permit more patients with CNS metastases to engage in PD-1 or PDL1 blockade therapy and explore the safety of PD-1 or PD-L1 inhibitors in patients with CNS metastases.