Prognostic implication of EGFR mutation status and subtype in resected lung adenocarcinoma patients irrespective of therapy.

Abstract

This study aimed to investigate the pure prognostic role of epidermal growth factor receptor (EGFR) mutation status and subtype in lung adenocarcinoma patients irrespective of therapy. We retrospectively enrolled 119 cases of completely resected pathological stage I lung adenocarcinoma patients who received no postoperative chemotherapy or tyrosine kinase inhibitors. EGFR gene mutations from 18 to 21 exons were tested for all the patients. Disease-free survival (DFS) and overall survival (OS) were compared between patients with different EGFR mutation status and subtype using Kaplan-Meier methods. EGFR mutations were detected in 54 (45.4%) patients including two common mutation subtypes: 32 in-frame deletion within exon 19 (19del) and 19 point mutation within exon 21 (L858R). The frequency of EGFR mutations was much greater for patients of non-smokers versus current or ever smokers (58.1 versus 24.4%, P = 0.000), and a little greater for females versus males (53.8 versus 35.2%, P = 0.042). The median follow-up duration was 43.5months, and there were no differences on DFS (P = 0.461) and OS (P = 0.989) between patients with EGFR mutations and those without in univariate analysis. The patients harboring 19del mutation had a better DFS (P = 0.028) and OS (P = 0.001) than the patients harboring L858R mutation with significant statistical difference. This study suggests that there is no difference on survival between patients with EGFR mutations and those without, but the patients harboring EGFR 19del mutation have survival advantage compared to those harboring EGFR L858R mutation.