Prognostic Value of Lymphovascular Invasion in Stage Ⅱ Colorectal Cancer Patients with an Inadequate Examination of Lymph Nodes.

BackgroundLymphovascular invasion (LVI) is defined as the existence of cancer cells in lymphatics or blood vessels. This study aimed to evaluate the prognostic value of LVI in stage Ⅱ colorectal cancer (CRC) patients with inadequate examination of lymph nodes (ELNs) and further combined LVI with the TNM staging system to determine the predictive efficacy for CRC prognosis. Adjuvant chemotherapy (ACT) was then evaluated for stage Ⅱ CRC patients with LVI positivity (LVI +).MethodsThe clinicopathologic records of 1420 CRC patients treated at the Third Affiliated Hospital of Soochow University between February 2007 and February 2013 were retrospectively reviewed. LVI was examined by hematoxylin-eosin (HE) staining. Kaplan-Meier analysis followed by a log-rank test was used to analyze survival rates. Univariate and multivariate analyses were performed using a Cox proportional hazards model. The Harrell’s concordance index (C-index) was used to evaluate the accuracy of different systems in predicting prognosis.ResultsThe LVI status was significantly associated with pT stage, degree of differentiation, tumor stage, serum CEA and CA19-9 levels, perineural invasion (PNI) and KRAS status. The 5-year overall survival (OS) rate of stage Ⅱ patients with < 12 ELNs and LVI + was less than stage ⅢA. Multivariate analyses showed that LVI, pT-stage, serum CEA and CA19-9 levels, PNI and KRAS status were significant prognostic factors for stage Ⅱ patients with < 12 ELNs. The 8th TNM staging system combined with LVI showed a higher C-index than the 8th TNM staging system alone (C-index, 0.895 vs. 0.833). Among patients with LVI + the ACT group had a significantly higher 5-year OS and 5-year disease-free survival (DFS) than the surgery alone (SA) group (5-year OS, 66.7% vs. 40.9%, P = 0.004; 5-year DFS, 64.1% vs. 36.3%, P = 0.002).ConclusionsLVI is an independent prognostic risk factor for stage Ⅱ CRC patients. Combining LVI with the 8th TNM staging system improved the predictive accuracy for CRC prognosis. ACT in stage Ⅱ CRC patients with LVI + is beneficial for survival.