Clinicopathologic Predictors of Outcome and Implications for Adjuvant Therapy in Pathologic Stage II Non-small Cell Lung Cancer.

[BACKGROUND/AIM] Pathologic stage II non-small cell lung cancer (NSCLC) exhibits heterogeneous outcomes despite curative resection. Although adjuvant EGFR-TKI and immunotherapy have improved survival in resected NSCLC, subgroup analyses from major trials show only modest benefit in stage II disease. Given these limited gains and the variable cost-effectiveness of adjuvant therapy across regions, identifying prognostic factors is essential to guide treatment decisions and support value-based precision care.

[PATIENTS AND METHODS] We retrospectively analyzed 115 patients with pathologic stage II NSCLC (27 IIA, 88 IIB) who underwent complete resection at a tertiary hospital in Taiwan (2016-2023). Clinicopathologic variables-including histologic subtype, spread through air spaces (STAS), and lymphovascular invasion (LVI) - were reviewed. Recurrence-free survival (RFS) and overall survival (OS) were evaluated using Kaplan-Meier and Cox proportional hazards analyses.

[RESULTS] The 5-year RFS and OS rates were 50.9% and 67.9%, respectively. Independent predictors of recurrence included tumor size >4 cm [hazard ratio (HR)=2.88, =0.008], N1 nodal status (HR=3.20, =0.016), and high-risk adenocarcinoma subtype (micropapillary/solid; HR=2.80, =0.014). Adjuvant chemotherapy significantly improved OS (76.4% . 37.2%, =0.002).

[CONCLUSION] Tumor size, nodal involvement, and histologic subtype are key prognostic determinants in stage II NSCLC. Identifying high-risk patients is crucial to optimize selection for adjuvant immunotherapy or targeted therapy and to ensure clinical and economic benefit.