To investigate the risk factors of vascular invasion in patients with colorectal cancer, and to explore the influence of vascular invasion on the prognosis.

The clinicopathological data of 319 patients with colorectal cancer who underwent radical resection from January 2010 to December 2013 in the Huaiyin People′s Hospital of Jinan were retrospectively analyzed, surgical specimens in all patients were collected and detected by immunohistochemical staining. The relationship between vascular invasion and clinicopathological factors of colorectal cancer were analyzed by chi square test or Fishers exact test. The influence of vascular invasion on overall survival was investigated with Kaplan-Meier curve, and the independent risk factors influencing vascular invasion were identified with Logistic regression.

The incidence of vascular invasion in patients with low differentiated tumor was 37.08%(33/89), which was significantly higher than that in those with middle-high differentiated tumor 25.65% (59/230), and the difference was statistically significant (χ²=4.08, P=0.043). Vascular invasion detection rate was higher in T3 (31.33%, 26/83) and T4 (34.09%, 60/176) group than those in T1 (11.11%, 1/9)and T2 (9.80%, 5/51)(χ²=12.99, P=0.005). Tumors of 52 cases located in the ascending colon, 27 cases in the transverse colon, 19 cases in the descending colon, 53 cases in the sigmoid colon, and 168 cases in the rectum, the vascular invasion rates were 28.85%(15/52), 7.41%(2/27), 10.53%(2/19), 20.75%(11/53), 36.90%(62/168) respectively, the difference was statistically significant(χ²=16.16, P=0.003). The incidence of vascular invasion in patients with lymph node metastasis was 41.53%(49/118), which was significantly higher than that in those without lymph node metastasis (21.39%, 43/201) (χ²=14.68, P=0.000). The results of multivariate analysis showed that T3, T4 state (RR=6.563, 95%CI=0.302-0.992, P=0.047) and lymph node metastasis (RR=5.618, 95%CI=1.142-2.293, P=0.007) were independent risk factors for vascular invasion in colorectal cancer patients. Among 319 colorectal cancer patients, 297 patients were followed up (93.10%) for 8-71 months, the median follow-up time was 38 months. The 5-year survival rate was 45.12% in patients with vascular invasion and 59.93% without vascular invasion, which was significantly different (χ²=4.99, P=0.025).

The risk of vascular invasion is higher in colorectal cancer patients with T3, T4 state and lymph node metastasis, vascular invasion is a poor prognostic factor in colorctal cancer patients.