EGFR mutation status in non-small cell lung cancer receiving PD-1/PD-L1 inhibitors and its correlation with PD-L1 expression: a meta-analysis

Meta-analysis was performed on the Web of Science, PubMed, Embase, and Cochrane databases to evaluate the effect of epidermal growth factor receptor (EGFR) mutation status on programmed cell death protein 1/programmed death ligand 1 (PD-1/PD-L1) immune checkpoint inhibitors, and the association between EGFR mutation status and PD-L1 expression in non-small cell lung cancer (NSCLC) patients. Pooled effect (hazard ratio/odds ratio, HR/OR) with 95% confidence interval (CI) was calculated, and the source of heterogeneity was explored by subgroup analysis and meta-regression using Stata/SE 15.0. Meta-analysis of the association between EGFR mutation status and overall survival (OS) in NSCLC with immunotherapy was calculated from four randomized controlled trials. We found that immune checkpoint inhibitors significantly prolonged OS over docetaxel overall (HR 0.71, 95% CI 0.64-0.79) and in the EGFR wild type (HR = 0.67, 95% CI = 0.60-0.75), but not in the EGFR mutant subgroup (HR = 1.11, 95% CI = 0.80-1.52). Meta-analysis of the association between EGFR mutation status and PD-L1 expression in NSCLC included 32 studies. The pooled OR and 95% CI were 0.60 (0.46-0.80), calculated by random effects model. No source of heterogeneity was found in subgroup analysis. Sensitivity analysis was carried out with a fixed model, and the influence of a single study on the pooled results showed no significant change with robust meta-analysis methods. Harbord's weighted linear regression test (P = 0.956) and Peters regression test (P = 0.489) indicated no significant publication bias. The limited benefit of single-agent PD-1/PD-L1 inhibitors in the second-line or later setting for EGFR-mutated NSCLC may be partly due to the lower expression of PD-L1.