P2.16-04 Prognostic Value of Lymphovascular Invasion and Its Effect on Patterns of Recurrence in T1-3N0 Non-Small Cell Lung Cancer

The purpose of this study is to clarify the prognostic value of lymphovascular invasion (LVI) in patients with surgically resected T1-3N0 non-small cell lung cancer (NSCLC) according to the eighth edition of the TNM Classification of the American Joint Committee on Cancer (AJCC). A total of 442 NSCLC patients who received curative surgery and were confirmed with pathologic T1-3N0 between March 2000 and August 2015 were reviewed. The pathological stages were re-evaluated according to the eighth edition of the TNM Classification of the AJCC. The 5-year recurrence-free survival (RFS) rate for total cohort was 69.7%, and the 5-year overall survival (OS) rate was 78.0%. LVI was present in 89 patients (19.9%). The presence of LVI decreased the 5-year RFS rate significantly (47.5% vs. 72.3%, p < 0.001) and the 5-year OS rate (62.5% vs. 81.1%, p < 0.001). The differences between LVI group and non-LVI group were more remarkable in T2a-bN0 staged patients compared with T1a-c staged patients (T1a-c patients: 63.6% vs. 78.0%, p = 0.004; T2a-b patients: 31.7% vs. 64.9%, p = 0.027, respectively). Multivariate analysis revealed that the presence of LVI was a significant predictor for RFS (p < 0.001) but an insignificant factor for OS. In T2a-bN0 staged patients, the 5-year OS rate was significantly lower in patients with LVI than in patients without LVI (50.0% vs. 74.4%, p = 0.045), whereas T1a-c staged patients did not show a significant difference in 5-year OS according to the presence of LVI (p = 0.196). LVI is a significant associated factor for RFS in patients with stage T1-3N0 NSCLC. Prognostic impact of LVI is more remarkable in patients with more than T2N0 stage compared to patients with the T1N0 disease.