Excision of trocar sites reduces tumor implantation in an animal model

PURPOSE: The purpose of this study was to determine the effect of excising abdominal trocar wound sites after pneumoperitoneum on the rate of trocar site tumor implantation in a hamster model. This would help determine whether tumor cells seed trocar sites during or after pneumoperitoneum. METHODS: A total of 0.5 ml of GW-39 human colon cancer cell suspension at 2.5 percent v/v (8×105 cells) was injected into the abdomens of 77 hamsters through a midline incision. Animals were subjected to ten minutes of pneumoperitoneum, after placement of four abdominal trocars, and then randomly assigned to undergo either simple suture closure or 4-mm radius trocar wound site excision at the end of the procedure. Gross and microscopic tumor implants were documented seven weeks later. RESULTS: There were three and four deaths in simple suture closure and wound site excision groups, respectively. Of the remaining 35 hamsters in each group, tumor cells implanted at 89 and 78 percent of trocar sites, respectively (P<0.03). There was no significant difference between the two groups in tumor implantation at midline laparotomy sites. Wound site excision also resulted in fewer palpable tumors (44vs. 61 percent;P<0.01) and a lower tumor implantation rate (49vs. 74 percent;P<0.05) at all four concurrent sites compared with simple suture closure. CONCLUSIONS: Excision of laparoscopic abdominal trocar wound sites can significantly, but not completely, reduce tumor implantation rate compared with simple wound closure.