Proposal on incorporating lymphovascular invasion as a T-descriptor for stage I lung cancer

Background Lymphovascular invasion (LVI) and Visceral Pleural Invasion (VPI) have been reported to be risk factors for stage I Non-Small Cell Lung Cancer (NSCLC). However, only VPI was incorporated into the current 8th Tumor–Node–Metastasis (TNM) classification. This study aimed to explore the prognostic effect of LVI and VPI on TNM staging in pathological stage I NSCLC. Method We retrospectively reviewed 2633 consecutive p-stage I NSCLC patients in the Shanghai Chest Hospital (2008–2012). By using the Kaplan–Meier method and Cox proportional hazard regression model, we identified the correlations between LVI, VPI, and clinical outcomes in p-stage 1 NSCLC. Results Of all 2633 p-stage I NSCLC patients, 222 were pathologically diagnosed with LVI and 836 pathologically with VPI. The 5-year recurrence free survival (RFS) and overall survival (OS) rates of patients with LVI was significantly worse compared to those without LVI (61.2% vs 82.0%, p < 0.001; 73.3% vs 88.1%, p < 0.001). The same results emerged for patients with VPI (70.1% vs 85.9%, p < 0.001; 82.3% vs 90.0%, p < 0.001). Using the univariable and multivariable analysis, we found that when tumor diameter was 3 cm or smaller, LVI (RFS: hazard ratio [HR], 2.54; 95% confidence interval [CI], 1.86–3.50; p < .001; OS: HR, 2.53; 95% CI, 1.72–3.71; p < .001) and VPI (RFS: HR, 2.14; 95% CI, 1.71–2.67; p < .001; OS: HR, 1.56; 95% CI, 1.12–2.04; p = 0.01) were significant prognostic factors for RFS and OS. When tumor size was between 3–4 cm, LVI (HR, 1.84; 95% CI, 1.03–3.29; p = 0.039) and VPI (HR, 2.56; 95% CI, 1.61–4.07; p < .001) were associated with inferior OS. Conclusions The presence of LVI significantly affected OS and RFS in stage I NSCLC patients. Our results suggested that it might be better to incorporate LVI as a T descriptor as VPI in the further TNM classification.