Adjuvant chemotherapy for completely resected stage IB-IIA non-small cell lung cancer according to the AJCC 8th edition staging system: a real-world retrospective cohort study based on the SEER database

Transl Lung Cancer Res. 2026 Mar 23;15(3):48. doi: 10.21037/tlcr-2025-1-1403. Epub 2026 Feb 26.

ABSTRACT

BACKGROUND: Whether adjuvant chemotherapy confers greater survival benefit than observation alone in patients with completely resected stage IB-IIA non-small cell lung cancer (NSCLC), particularly those with high-risk features, remains unclear. This study evaluates both overall survival (OS) and lung cancer-specific survival (LCSS) to assess the efficacy of adjuvant chemotherapy in a real-world setting.

METHODS: We analyzed surgically resected stage IB-IIA [American Joint Committee on Cancer (AJCC) 8th edition] NSCLC patients from the Surveillance, Epidemiology, and End Results (SEER) database [2007-2021]. Multivariate Cox and Fine and Gray's competing risk regression models were applied to identify prognostic factors and to adjust for covariates in subgroup analyses.

RESULTS: Among 25,919 NSCLC patients, only 14.6% with high-risk features received adjuvant therapy. Adjuvant therapy was an independent favorable prognostic factor for OS [hazard ratio (HR) 0.89, 95% confidence interval (CI): 0.84-0.95, P<0.001], but not for LCSS [subhazard ratio (SHR) 1.04, 95% CI: 0.97-1.12, P=0.29] in the entire cohort. Subgroup analyses showed no survival benefit for stage IB patients, regardless of high-risk features status. In contrast, stage IIA patients receiving adjuvant therapy had significantly improved OS (HR 0.75, 95% CI: 0.67-0.83, P<0.001) and LCSS (SHR 0.87, 95% CI: 0.76-0.99, P=0.044). The benefit was most pronounced in stage IIA patients with high-risk features (OS: HR 0.69, 95% CI: 0.60-0.79, P<0.001; LCSS: SHR 0.76, 95% CI: 0.64-0.90, P=0.001).

CONCLUSIONS: This study provides real-world evidence that adjuvant chemotherapy was associated with improved OS and LCSS outcomes in completely resected stage IIA NSCLC, particularly among those with high-risk features; however, it was not associated with improved survival in stage IB patients, regardless of their risk status.

PMID:41982691 | PMC:PMC13071739 | DOI:10.21037/tlcr-2025-1-1403