Effect of epidermal growth factor receptor mutation on early-stage non-small cell lung cancer according to the 8th...

This study evaluated the effect of EGFR mutation on early-stage non-small cell lung cancer (NSCLC) based on the 8th TNM classification.

The study retrospectively examined 1231 patients who underwent curative resection for pathological stage 0-I (8th TNM classification) NSCLC and EGFR mutation analysis from January 2006 to December 2018 at Kanagawa Cancer Center. The disease-free survival (DFS), overall survival (OS) and disease-specific survival (DSS) of EGFR-mutant lung cancer (Mt) and EGFR wild-type lung cancer (Wt) patients at each stage were compared between two patient groups using the log-rank test. Cox regression analyses were performed to identify prognostic factors.

The number of stage 0, IA1, IA2, IA3, and IB Mt/Wt patients was 79/92, 202/189, 145/144, 45/75, and 74/186, respectively. There was no statistically significant difference in DFS between Mt and Wt patients at any pathological stage. The 5-year OS of Mt/Wt patients was 96.9 %/98.5 % for stage 0 (p = 0.671), 92.2 %/92.2 % for stage IA1 (p = 0.997), 93.9 %/82.6 % for stage IA2 (p = 0.039), 87.3 %/91.4 % for stage IA3 (p = 0.768), and 85.3 %/69.3 % for stage IB (p = 0.017). The 5-year DSS of Mt/Wt patients was 95.7 %/95.4 % for stage IA2 (p = 0.684) and 93.2 %/77.5 % for stage IB (p = 0.016). In Cox regression analyses, Mt was not identified as a prognostic factor for OS among stage IA2 NSCLC patients (HR, 0.62; 95 % CI, 0.20-1.93; p = 0.413). However, Mt was a favorable prognostic factor for OS (HR, 0.44; 95 % CI, 0.19-1.00; p = 0.049) and DSS (HR, 0.38; 95 % CI, 0.17-0.87; p = 0.022) among stage IB NSCLC patients.

EGFR mutation had no effect on the prognosis of stage 0-IA NSCLC but significantly affected the OS and DSS of stage IB NSCLC. Effect of EGFR mutations on postoperative prognosis of patients with stage 0-I NSCLC differed with each stage.