title: EGFR mutations and clinical outcomes of chemotherapy for advanced non-small cell lung cancer: a meta-analysis.
abstract: 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.
  
  
  METHODS
  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; I(2)=75.9%; P<0.001) with significant heterogeneity.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Tumor Research and Therapy Center, Provincial Hospital Affiliated to Shandong University, 324 Jingwu Weiqi Road, Jinan, Shandong 250021, PR China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Tumor Research and Therapy Center, Provincial Hospital Affiliated to Shandong University, 324 Jingwu Weiqi Road, Jinan, Shandong 250021, PR China.
authors.forename: Hong-Hai
authors.initials: HH
authors.lastname: Dai
authors.affiliation: School of Public Health, Shandong University, 44 Wenhuaxi Road, Jinan, Shandong 250012, PR China; Wanhua Chemical Group Co., Ltd., 7 South Xingfu Road, Yantai, Shandong 264002, PR China.
authors.forename: Hong-Yun
authors.initials: HY
authors.lastname: Dong
authors.affiliation: Tumor Research and Therapy Center, Provincial Hospital Affiliated to Shandong University, 324 Jingwu Weiqi Road, Jinan, Shandong 250021, PR China.
authors.forename: Cheng-Tao
authors.initials: CT
authors.lastname: Sun
authors.affiliation: Tumor Research and Therapy Center, Provincial Hospital Affiliated to Shandong University, 324 Jingwu Weiqi Road, Jinan, Shandong 250021, PR China. Electronic address: sdslyyyz@sina.com.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Tumor Research and Therapy Center, Provincial Hospital Affiliated to Shandong University, 324 Jingwu Weiqi Road, Jinan, Shandong 250021, PR China. Electronic address: hanjq1960@126.com.
authors.forename: Jun-Qing
authors.initials: JQ
authors.lastname: Han
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D066246:ErbB Receptors / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D009154:Mutation; D009367:Neoplasm Staging; D016017:Odds Ratio; D017594:Publication Bias; D016896:Treatment Outcome
chemical_list: D066246:ErbB Receptors
keywords: Chemotherapy; EGFR; Meta-analysis; Mutation status; Non-small cell lung cancer; Response rate