Association between the Epidermal Growth Receptor Status and the Efficacy of First-line Chemotherapy in Patients with Advanced Non-small Cell Lung Cancer

Background and objective Status of epidermal growth factor receptor (EGFR) gene is a predictor of response to EGFR tyrosine kinase inhibitor (TKI). However, little is know about the relationship between EGFR status and response to chemotherapy. We evaluated the prediction value of EGFR mutation status on response to first-line chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC). Methods The data of 181 patients with stage IIIb/IV NSCLC who diagnosed by histopathology from January 10, 2006 to December 20, 2013 in Beijing Chest Hospital, Capital Medical University were collected. The relationships between EGFR gene status, clinical characteristics and response and progression-free survival (PFS) were analyzed. Results All of the 181 patients’ EGFR statuses were determined. 75 (41.4%) patients harbored EGFR-activating mutations and 106 (58.6%) patients were EGFR wild-type. All patients received first-line chemotherapy. The objective response rate (ORR) was 26.0% and disease control rate (DCR) was 70.2%. Patients with EGFR-activating mutations had a higher DCR than patients with EGFR wild-type (84.0% vs 60.4%, P=0.001) did. Subgroup analysis showed that the ORR and DCR in patients with EGFR exon 19 deletions were remarkably higher than those with EGFR wild-type (P = 0.049, 0.002, respectively). The DCR in patients with EGFR exon 21 L858R mutation was significantly higher than that in patients with EGFR wild-type (P=0.010). 168 patients were available for response evaluation in all of 181 patients and median PFS was 4.3 mo. The PFS of patients with adenocarcinoma was significantly higher than that patients with squamous cell carcinoma (4.7 mo vs 3.0 mo, P=0.036). The PFS in patients harbored EGFR-activating mutations was significantly higher than that in the patients with EGFR wild-type (6.3 mo vs 3.0 mo, P=0.002). The PFS of patients with a performance status (PS) of 0-1 was significantly higher than that in patients with a PS of 2 (4.4 months vs. 0.7 months, P= 0.016). Cox multivariate analysis indicates the EGFR-activating mutation is an independent factor affecting PFS (HR=0.654, 95%CI: 0.470-0.909, P=0.012). Conclusion EGFR-activating mutation is a predictor for PFS of first-line chemotherapy in advanced NSCLC patients.