The Role of Mutation Status of the Epidermal Growth Factor Receptor Gene In Advanced Non–Small Cell Lung Cancer

Objective. The aim of this study was to examine the prevalence of epidermal growth factor receptor (EGFR) gene mutations among patients with advanced nonsquamous non–small cell lung cancer (NSCLC) treated in our institution and to evaluate the associations between EGFR mutations and clinicopathological characteristics.
Materials and Methods. A total of 103 patients with NSCLC were examined from April 2010 to September 2011. The patients were screened for EGFR mutations in exons 19 and 21 using sequence analysis.
Results. EGFR mutations were detected in 10 patients (9.71%): 23.1% of women and 5.2% of men (P<0.05), 31.8% of never-smokers and 4.7% of smokers (P<0.05), and 12.3% of patients with adenocarcinomas and 6.25% of patients with large cell carcinomas (P>0.05). Eight mutations (80.0%) were found in exon 21: 7 patients had the L858R mutation and 1 patient had the L861G mutation. Two mutations (20.0%) were found in exon 19: 1 patient had the L747-A748 deletion and 1 patient had the L747-A750insE deletion. The overall response rate was significantly greater in the EGFR mutation-positive group than in the EGFR mutation-negative or control groups (P<0.05). The median progression-free survival in the EGFR mutation-negative group and the control group that received systemic standard chemotherapy was 5.6 months (95% CI, 4.3 to 7.0) and 5.3 months (95% CI, 4.9 to 5.7), respectively, but it was not achieved in the EGFR mutation-positive group that received EGFR tyrosine kinase inhibitors (P<0.05).
Conclusions. The frequency of EGFR mutations in our patients with nonsquamous NSCLC was found to be similar to that reported in Europe. EGFR mutations were more frequent in women and never-smokers