To investigate the effect of intraperitoneal implantation of 5-fluorouracil(5-Fu) intraperitoneally on immune function and expression of miR-34a and ZEB2 in patients with colorectal cancer.

From January 2014 to December 2016, ninety-two patients with colorectal cancer who underwent radical surgery in Xianyang Hospital of Yan'an University were selected. They were divided into 2 groups using random number table method, with 46 cases in each group. Patients in the control group underwent elective laparoscopic radical resection of colorectal cancer under general anesthesia. The observation group was given 5-Fu implantation before abdominal closure, and nutritional support and prophylactic antibiotics were given to both groups after operation. The survival rate, relapse rate, immune function, and the expression of miR-34a and ZEB2 between two groups were compared.

(1) There was no significant difference in postoperative hospital stay between the two groups (t=0.251, P=0.401). The disease-free survival time of the observation group was (10.26±1.29) months, which was significantly longer than that of the control group (8.92±1.02) months (t=-5.526, P<0.01). The 1-year survival rate of the control group and observation group was 78.26% (95% CI=72.13%-84.39%) and 95.65% (95% CI=93.91%-97.39%), respectively, with statistically significant difference between the two groups (χ²=5.896, P=0.015). (2) After treatment, all immune indicators in the two groups showed a significant increase after fall trend (P<0.05). The IgM level in the observation group was significantly higher than that in the control group at 2 d after operation (P<0.05), and the levels of IgA and CD4⁺ in the observation group were significantly lower than those in the control group at 2 d after operation (P<0.05). (3) There were no significant differences in serum miR-34a and ZEB2 protein levels between the two groups before treatment (t=-1.097, 1.392; P=0.259, 0.138). 7 days after treatment, miR-34a in both groups was significantly increased (t=3.975, -3.718; P=0.001, 0.005), ZEB2 was significantly decreased (t=6.279, 4.183; both P<0.001), but the changes of observation group were higher than the control group (t=-2.813, 4.118; P=0.029, <0.001).

Intraperitoneal implantation of 5-Fu in colorectal cancer patients has no significant effect on the 1-year survival rate and recurrence rate, but it has a certain inhibitory effect on the immune function of patients. It can improve the low expression of miR-34a and inhibit the high expression of ZEB2.