Prognostic impact of invasive features in completely resected NSCLC stratified by tumor diameter

In node-negative non-small cell lung cancer (NSCLC), only Pleural invasion (PI) is reflected in the current TNM staging, whereas the prognostic roles of Lymphatic invasion (LI) and Vascular invasion (VI) remain poorly defined. Moreover, the variation in their prognostic impact across tumor size strata is not well understood. This study aimed to evaluate the prognostic impact of PI, LI, and VI on recurrence-free survival (RFS) in node-negative NSCLC, stratified by tumor size.

We retrospectively analyzed 692 patients with completely resected, node-negative NSCLC. Cases of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) were excluded from the analysis. Patients were categorized into three cohorts: Cohort1 (size:　≦ 2.0 cm), Cohort2 (> 2.0 cm ≦ 3.0 cm), and Cohort3 (> 3.0 cm ≦ 5.0 cm). Multivariate Cox regression analysis was performed to identify independent prognostic factors .

In Cohort 1, PI (Hazard Ratio [HR]: 2.87, 95% Confidence Interval [CI]: 1.21-6.78, P = 0.02) was independent prognostic factors for worse RFS. In Cohort 2, only LI was significantly associated with recurrence (HR:3.62, 95% CI: 1.31-5.62, P = 0.01). In Cohort 3, both PI (HR:2.67, 95% CI: 1.24-5.79, P = 0.01) and LI (HR: 6.27, 95% CI: 2.79-14.1, P < 0.001) were independent predictors of poor prognosis, with LI demonstrating a more substantial impact than PI. VI showed limited prognostic value in larger tumors.

The prognostic relevance of PI, LI, and VI in NSCLC varies by tumor size. PI plays a critical role in small tumors, while LI becomes increasingly influential with larger tumors. These findings suggest the need for size-specific pathological risk assessment to guide postoperative management and consideration of adjuvant therapy.