MA01.01 Proposal on Incorporating Lymphovascular Invasion as a T-Descriptor for Stage I Non-Small Cell Lung Cancer

Abstract

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 at exploring the prognostic impact of LVI on TNM staging in Pathological Stage I NSCLC. We retrospectively reviewed 2600 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 I NSCLC. Of all p-stage I NSCLC 2600 patients, 221 were pathologically diagnosed with LVI and 815 pathologically with VPI, respectively. It was observed that patients with LVI had an unfavorable lung cancer specific survival (LCSS) (hazard ratio [HR]: 1.883; 95% confidence interval [CI]: 1.351-2.625; P < 0.001) and recurrence-free survival (RFS) (HR: 2.025; 95% CI: 1.560-2.630; P < 0.001). The 5-year RFS rates of patients with LVI was significantly worse than those without LVI (61.2% VS 82.7%, P< 0.001). Patients with LVI exhibit similar prognosis (HR: 2.538; 95% CI: 1.570-4.098; P < 0.001) compared with that of VPI in pN0 non-small-cell lung cancer and a tumor diameter of 3cm or smaller. When tumor size was between 3-4cm, patients with LVI and VPI were associated with inferior prognosis than those with only LVI or VPI (P < 0.001). The presence of LVI independently and significantly affects LCSS and RFS in patients with stage I NSCLC. Our results suggest that stage T1a-1c(IA) patients with LVI should be upstaged to T2a(IB), meanwhile, stage T2a(IB) patients coexist with LVI and VPI should be upstaged again in the TNM classification.