Evaluating the prognostic impact of EGFR mutation on adjuvant chemotherapy efficacy in grade 3 stage IB lung adenocarcinoma

Abstract

Objectives

Adjuvant chemotherapy (ACT) for patients with stage IB lung adenocarcinoma (LUAD) is controversial, particularly in those with epidermal growth factor receptor (EGFR) mutations. This study aims to evaluate the efficacy of ACT in stage IB LUAD with Grade 3 and explore the prognostic impact of EGFR mutations status on chemotherapy effectiveness.

Methods

We identified 707 high-risk (Grade 3) stage IB LUAD patients who underwent complete resection between 2014 and 2018. The Kaplan-Meier curves was used to assess recurrence-free survival (RFS) and overall survival (OS). Prognostic factors were evaluated using the Cox proportional hazards model, and propensity score matching was applied to reduce bias from confounding variables.

Results

In the entire cohort, patients who received ACT showed significantly better 5-year RFS and OS compared to those who did not (P < 0.001 for both). Among 247 patients without EGFR mutations, 125 (50.6 %) received ACT and 122 (49.4 %) did not. In the propensity score-matched cohort of 84 pairs, those treated with ACT had significantly better 5-year RFS and OS (P < 0.01 for both). Among 460 patients with EGFR mutations, 237 (51.5 %) received ACT and 223 (48.5 %) did not. In the matched cohort of 184 pairs, ACT recipients had significantly better prognoses. Multivariable analysis confirmed ACT was an independent prognostic factor, while EGFR mutation status was not.

Conclusions

ACT significantly improves the prognosis of patients with Grade 3 stage IB LUAD, irrespective of EGFR mutation status. These findings support the clinical adoption of ACT for this patient subgroup.