OBJECTIVETo study the antitumor effect of peri-tumor implantation of delayed-release 5-fluorouracil implants on xenograft colorectal tumor in mice.

METHODSFifty tumor-bearing nude mice were randomly divided into 5 groups. Group A and B were treated with peri-tumor implantation of 5-fluorouracil implants and the dose of 5-fluorouracil was 200 and 100 mg/kg, respectively. Group C and D were treated with peri-tumor injection of 5-fluorouracil solution and the dose of 5-fluorouracil was 200 and 100 mg/kg, respectively. Group E did not receive any treatment. A growth curve was plotted for changes in tumor volume, the weight of the tumor was measured and tumor inhibition rate was calculated.

RESULTSThe growth curve was mild in group A and B and steep in group C, D and E. There were statistical differences in tumor volume between groups A and B and other groups and there were no statistical differences in tumor volume among group C, D and E. After 12 days, tumor inhibition rate was 72% in group A, 51% in group B, 8% in group C, and 5% in group C. There were statistical differences in inhibition rate between group A, B and C, D (P<0.05). The weight changes before and after the treatment among the 5 groups were not statistically different. During the study, 1 mouse in group A died, 4 in group C and 1 in group D.

CONCLUSIONDelayed-release 5-fluorouracil implants can effectively inhibit tumor growth.