EGFR mutations and clinical outcomes of chemotherapy for advanced non-small cell lung cancer: A meta-analysis

Background This meta-analysis was performed to assess whether epidermal growth factor receptor (EGFR) mutation status was associated with objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) in patients with advanced non-small cell lung cancer (NSCLC) treated with chemotherapy. Method We systematically identified eligible articles investigating the effects of chemotherapy in patients with NSCLC stratified by EGFR mutation status. The summary risk ratio (RR) for ORR and hazard ratios (HRs) for both PFS and OS were calculated using the inverse variance formula of meta-analysis. Results Identification for the current meta-analysis: 5 prospective studies (n=875) and 18 retrospective studies (n=1934) for ORR; 2 prospective studies (n=434) and 10 retrospective studies (n=947) for PFS; 2 prospective studies (n=438) and 7 retrospective studies (n=711) for OS. The ORR was significantly higher in patients with EGFR mutations in prospective studies (RR=1.42; 95% confidence interval [CI], 1.16–1.74; P=0.001), but not in retrospective studies (RR=1.12; 95% CI, 0.96–1.32; P=0.146). There was no obvious association between EGFR mutations and PFS both in prospective (HR=0.84; 95% CI: 0.65–1.09; P=0.197) and retrospective (HR=1.02; 95% CI: 0.87–1.18; P=0.838) studies. Association between EGFR mutations and OS was also not seen in prospective studies (HR=0.74; 95% CI: 0.27–2.05; P=0.566), but was seen in retrospective studies (HR=0.48; 95% CI: 0.33–0.72; P<0.001; I2=75.9%; P<0.001) with significant heterogeneity. Conclusion EGFR mutations in advanced NSCLC may be associated with higher ORRs to chemotherapy, but may have nothing to do with PFS and OS. Further prospective studies are required to identify the influence of EGFR mutations on chemotherapy effects in advanced NSCLC.