[Role of EGFR mutation status in patients with stage III non-squamous non-small cell lung cancer treated with chemoradiotherapy].

BACKGROUND AND OBJECTIVE: The presence of epidermal growth factor receptor (EGFR) mutations is predictive of a better response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) and initial chemotherapy in advanced non-squamous non-small cell lung cancer (NSCLC). The aim of this study is to analyze the association between the EGFR mutations and the outcome of combined chemoradiotherapy in stage III non-squamous NSCLC.

METHODS: Patients with stage III non-squamous NSCLC whose EGFR mutation status had been identified were retrospectively analyzed. The response of 87 patients to combined chemoradiotherapy, the two-year survival rate, and the response of 128 patients to initial chemotherapy were evaluated.

RESULTS: The response rate to combined chemoradiotherapy was 84.6% (33/39) in EGFR mutation-positive patients, significantly higher than the 56.3% (27/48) response rate in EGFR mutation-negative patients (P=0.004). Two-year survival rates were 53.8% and 50% in EGFR mutation-positive and mutation-negative patients, respectively. There was no significant difference in the overall survival for both patient groups. The overall response rate to initial chemotherapy was 34.5% (19/55) in EGFR mutation-positive patients, compared with the 21.9% (16/73) response rate in EGFR mutation-negative patients.

CONCLUSIONS: EGFR mutation-positive status can predict better response to combined chemoradiotherapy, but is not associated with overall survival in patients with stage III non-squamous NSCLC.