Adjuvant Chemotherapy for High-risk Pathologic Stage I Non-Small Cell Lung Cancer

This study aimed to investigate the efficacy of adjuvant chemotherapy for pathologic stage I non-small cell lung cancer (NSCLC) with high risk for recurrence.Prospectively collected data from 1278 patients with pathologic stage I NSCLC according to eighth edition staging guidelines who were undergoing lobectomy were retrospectively analyzed. Factors associated with high risk for recurrence were determined using the multivariable Cox proportional hazards model for recurrence-free survival (RFS). Survival was compared between patients who received adjuvant chemotherapy and those who did not.In multivariable analysis, age (≥70 years), invasive component size (>2 cm), visceral pleural invasion, lymphatic invasion, and vascular invasion were identified as independent factors for RFS. In patients with high-risk factors for recurrence such as pathologic T1c or T2a or lymphovascular invasion (high-risk group; n = 641), adjuvant chemotherapy resulted in significantly longer RFS and overall survival (n = 222; 5-year RFS, 81.4%; 5-year overall survival, 92.7%) than in patients who did not receive adjuvant chemotherapy (n = 418; 5-year RFS, 73.8%; P = .023; 5-year overall survival, 81.7%; P < .0001). In patients without any high-risk factors for recurrence (low-risk group; n = 637), RFS was not significantly different between those who received adjuvant chemotherapy (n = 83; 5-yeat RFS, 98.1%) and those who did not (n = 554; 5-year RFS, 95.7%; P = .30).Adjuvant chemotherapy may improve survival in patients with pathologic stage I NSCLC who have factors associated with high risk for recurrence, such as pathologic T1c or T2a or lymphovascular invasion.