Spread through air spaces as a prognostic factor in resected non-small cell lung cancer

Aims: To evaluate the prognostic impact of spread through air spaces (STAS) in patients with resected non-small cell lung cancer (NSCLC) and to investigate its association with clinicopathological features and survival outcomes. Methods: A retrospective analysis was conducted on 207 patients with pathological stage IA–IIIA NSCLC who underwent curative-intent surgery between 2018 and 2024. STAS was defined as the presence of micropapillary clusters, solid nests, or single tumor cells within alveolar spaces beyond the main tumor. Patients were categorized as STAS-positive or STAS-negative. Disease free survival (DFS) and overall survival (OS) were estimated using the Kaplan–Meier method. Univariate and multivariate Cox regression models were used to assess prognostic factors. Results: STAS was identified in 57% of patients. STAS positivity was significantly associated with poor differentiation, a higher rate of lymphovascular invasion, and increased use of adjuvant chemotherapy. Median DFS was 29.9 months in STAS-positive patients but was not reached in STAS-negative patients (p