Abstract
BACKGROUND: Adjuvant therapy for stage IB non-small cell lung cancer remains debatable. In this real-world study, we evaluate the efficacy and safety of adjuvant epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) for resected stage IB lung adenocarcinoma. METHODS: This real-world study recruited 249 patients diagnosed with stage IB disease after surgical resection between January 2013 and September 2021. Sixty-six (26.5%) patients received adjuvant targeted therapy (TKIs group), and 183 (73.5%) were enrolled in the clinical observation (CO) group. Propensity scores were matched to minimize the observed confounder effects between the two groups, and 59 patient pairs were matched. The primary endpoint was disease-free survival (DFS). RESULTS: In the TKI group, 38 (64.4%) patients chose to receive icotinib, 27.1% (16/59) received gefitinib, and 5 patients (8.5%) chose osimertinib. The median follow-up time was 30.8 months (range: 7-107 months). Two (3.4%) patients in the TKI group and 10 (16.9%) in the CO group experienced disease relapse. The 3-year DFS rates were 98.3% in the TKI group and 83.0% in the CO group (HR: 0.10; 95% CI: 0.01-0.78; p = 0.008). DFS differences were found in the entire cohort (p = 0.005) and the matched cohort (p = 0.024) between the two groups. Multivariate analysis showed that adjuvant EGFR-TKIs was an independent factor for DFS (HR: 0.211; 95% CI: 0.045-0.979; p = 0.047), along with poor cell differentiation (HR: 5.256; 95% CI: 1.648-16.769; p = 0.005), and spread through air spaces (HR: 5.612; 95% CI: 1.137-27.700; p = 0.034). None of the patients discontinued EGFR-TKIs owing to the low occurrence rate of treatment-related serious adverse events. CONCLUSION: Adjuvant EGFR-TKIs could significantly improve DFS among patients with stage IB lung adenocarcinoma compared with CO, with a safe and tolerable profile.