ABSTRACT
<p><b>OBJECTIVE</b>To study the the relationship between lymphatic vessel density (LVD) and distal intramural spread (DIS), and evaluate the value of LVD in determining the length of distal resection in low rectal cancer.</p><p><b>METHODS</b>Ninety-two samples from patients undergone curative resection of low rectal cancer were studied. DIS was detected by HE stain. LVD was examined by immunohisto-chemical LYVE-1 (lymphatic vessel endothelial hyaluronan receptor). The association of LVD with DIS and other clinicopathological factors were examined.</p><p><b>RESULTS</b>DIS (range 0.1-2.4 cm, mean 0.31 cm) was present in 44(47.8%) patients with low rectal cancer, including 23(52.3%) cases with cancer emboli in lymphatic vessels. LVD of peritumoral lesion was significantly higher than that of intratumoral lesion. LVD of DIS subgroup was significantly higher than that of non-DIS subgroup. Positive correlation was found by rank correlation test between the length of DIS and the LVD at peritumor tissue in DIS group (n=44, r=0.755, P<0.01). LVD was also positively correlated with the infiltration extent, lymphatic invasion and lymph node metastasis.</p><p><b>CONCLUSIONS</b>Lymphangiogenesis plays an important role in rectal cancer metastasis and cancer emboli in lymphatic vessels is the most common modality of DIS. The LVD is positively correlated with DIS, which may be helpful to determine the distal clearance length of rectal cancer.</p>