The Efficacy of Adjuvant EGFR-TKI Therapy for Stage IA Lung Adenocarcinoma with EGFR Mutations: A Retrospective Cohort Study

INTRODUCTION: Surgical resection is the standard for early-stage lung adenocarcinoma (LUAD), but recurrence remains a risk for patients with epidermal growth factor receptor (EGFR) mutations. The efficacy of adjuvant EGFR tyrosine kinase inhibitors (EGFR-TKIs) in stage IA LUAD is currently controversial. METHODS: This retrospective study evaluated 456 patients with stage IA EGFR-mutant LUAD. We compared survival outcomes between patients receiving adjuvant EGFR-TKIs (n = 60) and an observation group (n = 396). Subgroup analyses identified specific clinical features associated with treatment benefit. RESULTS: With a median follow-up of 75.87 months, exploratory analysis suggested a favorable trend toward improved 7-year disease-free survival (DFS) in the EGFR-TKI group compared with the observation group (92.2% vs. 80.0%; P = 0.027), although no significant difference was observed in overall survival. In the subgroup of patients with tumors containing solid components, postoperative EGFR-TKI therapy was associated with a potential improvement in 7-year DFS compared with observation (85.0% vs. 52.5%; P = 0.041). These findings are exploratory and require further validation. CONCLUSION: Postoperative adjuvant EGFR-TKI therapy was associated with a favorable long-term DFS trend in selected patients with stage IA EGFR-mutant LUAD, particularly in those with tumors containing solid components or other high-risk pathological features. However, this finding should be interpreted cautiously because the DFS advantage was not consistently statistically significant after landmark analysis to address immortal time bias, likely owing in part to the limited size of the treatment group.