Correlation Between EGFR Mutation Status And Response To First-line Platinum-based Chemotherapy In Patients With Advanced Non-small Cell Lung Cancer

Background and Objective:Lung cancer continues to be the main cause of carcinoma-related death throughout the world, and 75%-80% of these cancers are non-small cell lung cancer (NSCLC). The standard first-line regimen for advanced NSCLC is platinum-based doublet chemotherapy. However, there continues to be a lack of predictive biomarkers to select drugs for first-line chemotherapy. At present, epidermal growth factor receptor (EGFR) is the primary predictor of a curative effect of EGFR-tyrosine kinase inhibitors (EGFR-TKIs). But the prognostic and predictive value of EGFR mutation status in NSCLC remains uncertain. On this background, we reviewed the clinical outcomes in patients with advanced NSCLC who received platinum-based doublet therapies as first-line chemotherapy, and analyzed the predictive value of EGFR mutation status with regard to short-term effects and long-term survival in order to optimize the treatment of individual patients with advanced NSCLC.Methods:A total of 266 patients with stage IIIB or IV NSCLC who received platinum-based doublet therapies as first-line chemotherapy were investigated retrospectively, and their clinical data were assessed according to EGFR mutation.Results:EGFR mutations were identified in 45.5% of patients. There was no significant difference in response rate between EGFR mutation carriers and EGFR wild-type carriers (32.2% vs. 28.3%, P=0.484). Among the patients with Kirsten rat sarcoma viral oncogene homolog (KRAS) wild-type, however, those with EGFR mutations responded better to treatment than EGFR wild-type patients (46.2% versus 20.8%, P=0.043). The disease control rate associated with pemetrexed-based treatments was higher than for vinorelbine-based therapies in EGFR mutation patients (90.7% vs.58.1%, P=0.001). EGFR mutation was found in patients with longer progression-free survival (PFS) and median survival time, and improved 1-year and 2-year overall survival when compared with EGFR wild-type patients (6.2 versus 5.0 months, P=0.003; 18.9 versus 13.9 months, P=0.001; 81.0% versus 63.4%; and 33.9% versus 22.8%, respectively). Patients with the EGFR exon 19 mutation had longer PFS than those with EGFR exon 21 mutation(6.8 versus 5.9 months, P=0.005). Multivariate analysis showed that the response to first-line chemotherapy and the presence of EGFR mutations were independent prognostic factors in patients with advanced NSCLC.Conclusion:1. The presence of EGFR mutations meant longer PFS for patients with advanced NSCLC who received platinum-based doublet first-line chemotherapy, especially in those with the exon 19 deletion mutation.2. Among KRAS wild-type patients, those with EGFR mutation responded better to first-line chemotherapy than EGFR wild-type patients.