BACKGROUND: Postoperative recurrence is a significant problem in patients with early-stage non-small cell lung cancer (NSCLC), with recurrence rates of 35% for stage IB and 50% for stage IIA. This study aimed to evaluate the efficacy of tegafur-uracil (UFT) as an adjuvant therapy in NSCLC patients with poor prognostic factors. METHODS: A retrospective analysis was conducted of 330 patients with stage IB/IIA NSCLC who underwent lung resection between 2000 and 2019. Patients were divided into two groups based on the presence of poor prognostic factors (vascular, lymphatic, or pleural invasion or high pathological grade). Recurrence-free survival (RFS) and overall survival (OS) were compared between the UFT-treated and untreated groups using a Kaplan-Meier analysis. RESULTS: Among these patients, 85.8% had poor prognostic factors. In patients with poor prognostic factors, the 5-year RFS rates in the UFT and non-UFT groups were 74.3% and 62.6%, respectively (P=0.048), and the 5-year OS was 85.6% and 62.4%, respectively (P<
0.001). In patients without poor prognostic factors, UFT significantly extended OS (90.2% CONCLUSIONS: Postoperative adjuvant therapy with UFT significantly improved both RFS and OS in patients with stage IB/IIA NSCLC with poor prognostic factors. The administration of UFT should be considered in patients with high-risk early-stage NSCLC.