Detection and prognostic value of intratumoral and peritumoral lymphangiogenesis in colorectal cancer

Background: Colorectal cancer (CRC) with lymphatic invasion is one of the critical prognostic factors in lymph node metastasis. Lymphangiogencsis has a significant effect on lymphatic metastasis and tumor progression. However, the significance of intratumoral and peritumoral lymphangiogenesis has been controversial in CRC. The aim of this study is to investigate the different role of introtumoral and peritumoral lymphangiogenesis in CRC progression and prognosis. Methods: Lymphangiogenesis of 120 CRC specimens, as measured by lymphatic vessel density (LVD), was examined by immunostaining for podoplanin, a lymphatic vessel-specific marker. The mean number of lymphatic vessels of three hotspots was measured in intratumoral and peritumoral areas as intratumoral LVD (LVDit) and peritumoral LVD (LVDpt), respectively. The association of LVDit and LVDpt with the clinicopathological findings and prognosis was investigated. Results: Compared to the peritumoral lymphatics, the intratumoral lymphatics were small, collapsed and irregular. The mean LVDpt was higher than the mean LVDit (P<0.001). LVDit was positively correlated with tumor size (P=0.009), tumor histologic grade (P=0.023), and overall survival (P=0.036). LVDpt was correlated with lymph node metastasis (P<0.001), tumor stage (P=0.004), and overall survival (P=0.016). Conclusions: LVDpt plays a prominent role in lymph node metastasis, whereas LVDit is more closely correlated with tumor growth and histopathological differentiation. Both LVDpt and LVDit contribute to CRC progression and prognosis.