Epidermal Growth Factor Receptor Mutation Status and the Impact on Clinical Outcomes in Patients with Non-Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) mutation status differs according to ethnicity, gender, smoking history, and histology types. The present study aimed to evaluate EGFR mutation status in patients with non-small cell lung cancer (NSCLC) and further explore its association with clinical characteristics and prognosis in advanced NSCLC patients (Stage IIIB-IV). 238 NSCLC patients were enrolled in this study from October 2016 through December 2019. Patient characteristics and clinical data including age, gender, smoking history, histology types, tumor stage, survival status, and time were collected via electronic medical record system or telephone. 21 somatic mutations which spanned exons 18-21 of EGFR were detected using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method, followed by analysis of links to clinical characteristics, progression-free survival (PFS) and overall survival (OS). 103 patients were detected harboring EGFR mutations among the 238 cases tested (43.3%), and exons 19 and 21 were the highest mutation frequencies, with 20.6% and 19.3% respectively. The EGFR mutation rate was much higher in female versus male (57.4% vs 31.5%, p <0.001), in non-smokers compared to smokers (56.8% vs 25.9%, p <0.001), and in those with adenocarcinoma than other histology types (48.3% vs 3.7%, p <0.001). For patients in advanced stage, median PFS was 11 months in patients harboring EGFR mutations, versus 4 months in patients with wild type EGFR (p <0.001); median OS was 24 versus 12 months (p <0.001). Never smoking (p = 0.042) and adenocarcinoma (p = 0.007) were independent favorable factors for EGFR mutations. Our data strengthen the findings of high prevalence of EGFR mutations in Asian patients with NSCLC. Mutations are prevalent in those patients who are female, adenocarcinoma, and have never smoked. Moreover, advanced EGFR mutation-positive patients have better PFS and OS than those with wild type EGFR.