Prognostic value of visceral pleural invasion in non-small cell lung cancer: A propensity score matching study based on the SEER registry

Background and objectives: Visceral pleural invasion (VPI) is considered a poor prognostic factor in non-small cell lung cancer (NSCLC). We aimed to analyze the effect of VPI on cancer-specific survival, using propensity score matching (PSM) based on the Surveillance, Epidemiology, and End Results database. Methods: We identified 9901 patients with T1-2N0-2M0 who received segmentectomy, lobectomy, or pneumonectomy. Ten covariates were included in PSM. The effect of VPI on survival was assessed, stratified by nodal status and tumor size. Results: One-thousand and eighty-three pairs of patients were matched with standardized differences of covariates <10% after matching. We found that VPI was associated with a significantly worse survival (3-year survival rate: 84.6% vs. 75.9%, P = 0.005), especially in N0 (P < 0.001), but not in N1 or N2. No significant difference was observed between the extent of VPI. Moreover, VPI conferred a significantly worse survival in tumors >1-2 (P = 0.034) and >2-3 cm (P < 0.001), not <= 1, >3-4, or >4-5 cm in N0. Conclusions: VPI is a poor prognostic factor; but with increasing tumor size and nodal stage, its negative effect disappears. Our findings support current staging system which assigns higher T-stage for early >1-2 and >2-3 cm tumors.