Intratumoral as well as peritumoral lymphatic vessel invasion correlates with lymph node metastasis and unfavourable outcome in colorectal cancer.

The aim of this study was to assess the intratumoral and peritumoral distribution of lymphatic vessel density (LVD) and lymphatic vessel invasion (LVI) in colorectal cancer and their relationships with patients' clinicopathological characteristics and survival. Paraffin sections of 81 primary colorectal cancers were examined by immunohistochemical staining using monoclonal antibody D2-40. Peritumoral LVD was significantly higher than intratumoral LVD (P = 0.000). Both intratumoral LVD and peritumoral LVD were correlated with the presence of LVI (P = 0.006 and P = 0.003, respectively). LVI, intratumoral LVI and peritumoral LVI were identified, respectively in 38, 28 and 32% of the samples investigated. Both intratumoral LVI and peritumoral LVI were correlated with lymph node metastasis (P = 0.030 and P = 0.014, respectively). Lymph node metastasis, the presence of intratumoral LVI and peritumoral LVI were adversely associated with the 5-year overall survival in a univariate analysis (P = 0.001, P = 0.011 and P = 0.017, respectively). Multivariate analysis using Cox proportional hazard model showed that neither intratumoral LVI nor peritumoral LVI was an independent prognostic factor of overall survival. The results of this study demonstrated that intratumoral as well as peritumoral LVI was associated with lymph node metastasis and adverse outcome in colorectal cancer.