EGFR mutations are associated with prognosis but not with the response to front-line chemotherapy in the Chinese patients with advanced non-small cell lung cancer

The study aimed to investigate associations of tumor tissue EGFR mutations with response to the front-line chemotherapy and prognosis in advanced non-small cell lung cancer (NSCLC) patients. EGFR genotypes of 145 chemotherapy-naive patients with Stage IIIB and IV NSCLC were examined by using denaturing high-performance liquid chromatography (DHPLC). All patients received the front-line chemotherapy. There were 69 patients who received gefitinib therapy (32 as second-line and 37 as third-line therapy). About 37.9% (55/145) of the patients was detected to have EGFR mutations in their tumor tissue DNA. The response rate (RR, complete response plus partial response) to the chemotherapy for mutated EGFR carriers was 34.5% (19/55), similar to 33.3% (30/90) for wild-type EGFR carriers (P = 0.881). The patients with EGFR mutations had increased median survival time and 1- and 2-year survival rate than those with wild-type EGFR (23 vs 16 months, 86.38% vs 62.64%, 38.78% vs 27.16%, P = 0.0273). Among Stage IV NSCLC patients, mutated EGFR carriers had a longer progression-free survival (PFS) than wild-type EGFR carriers (5 vs 3 months, P = 0.040). Cox multivariate regression analysis showed that response to the front-line chemotherapy (RR vs PD) and EGFR mutation were independent prognostic factors (HR = 0.461, 95% CI: 0.271–0.783, P = 0.0042; HR = 0.598, 95% CI: 0.372–0.961, P = 0.0335, respectively) for patients with advanced NSCLC. We conclude that EGFR mutations in the Chinese patients with advanced NSCLC were not associated with response to the front-line chemotherapy, but Stage IV NSCLC patients with mutated EGFR had a longer PFS after the front-line chemotherapy. EGFR mutation is an independent prognostic factor for Chinese advanced NSCLC.