The role of EGFR mutation status in patients with stage III non-squamous non-small cell lung cancer treated with chemoradiotherapy.

Abstract

7032 Background: The presence of epidermal growth factor receptor (EGFR) mutations is predictive of a better response to EGFR-TKIs and initial chemotherapy in advanced non squamous non-small cell lung cancer (NSCLC). We reviewed EGFR mutation status in patients with non-squamous NSCLC, and then analyzed the association between the EGFR mutations and the outcome of combination chemoradiotherapy in stage III non-squamous NSCLC. Methods: Patients with stage III non-squamous NSCLC who had identified EGFR mutation status were retrospectively analyzed, 87 patients of those were evaluated response to combination chemoradiotherapy and 2 years survival rate, and128 patients of those could be evaluated response to initial chemotherapy. Results: The objective response rate to combination chemoradiotherapy was 84.6% (33/39) in patients with mutation-positive EGFR, significantly higher than 56.3% (27/48) in those with mutation-negative EGFR (P=0.004). By comparing the images of pre- and post-thoracic radiotherapy, the response rate to thoracic radiotherapy with or without concurrent chemotherapy was 79.5% (31/39) in patients with mutation-positive EGFR and 50% (24/48) in those with mutation-negative EGFR. The overall response rate to initial chemotherapy was 34.5% (19/55) in patients with mutation-positive EGFR, as compared 21.9% (16/73) in those with mutation-negative EGFR. Two years survival rate was 53.8% in patients with mutation-positive EGFR and 50% in those with mutation-negative EGFR. There was no difference in overall survival for patients with mutation-positive EGFR compared with those with mutation-negative EGFR. Conclusions: EGFR mutation-positive status can predict better response to combination chemoradiotherapy, but do not associate with overall survival in patients with stage III non-squamous NSCLC.