Efficacy of cytotoxic agents for the prevention of laparoscopic port-site metastases

Background: Recent experimental studies support initial clinical impressions that laparoscopic surgery for malignant neoplasms may be associated with an increased incidence of metastases to port sites. This study investigated in an experimental model the influence of cytotoxic agents (administered intraperitoneally or intramuscularly) on the development of port-site metastases following laparoscopic surgery. Methods: Seven days after the implantation of an adenocarcinoma in the left abdominal flank, 72 Dark Agouti rats underwent laparoscopy with carbon dioxide insufflation, instillation of an intraperitoneal agent, and intraperitoneal tumor laceration within the following study groups (12 rats in each group): (1) control (no intraperitoneal instillation); (2) intraperitoneal instillation of isotonic sodium chloride solution (0.9%); (3) intraperitoneal instillation of povodine-iodine (1:10 dilution of povidine-iodine and isotonic sodium chloride solution); (4) intraperitoneal instillation of methotrexate (0.125 mg of methotrexate in 3 mt of isotonic sodium chloride solution); and (5) intraperitoneal instillation of aqueous chlorhexidine acetate. Twelve additional rats underwent laparoscopic tumor laceration following intramuscular injection of 0.125 mg of methotrexate (no intraperitoneal agent). Rats were killed 7 days after the procedure, and the wounds were examined histologically by a blinded histopathologist for the presence of tumor metastases. Results: No tumor was found in any port site following the intraperitoneal administration of povidine-iodine (P =.04). In contrast, port-site metastases developed in the control group (5 [41.7%] of 12), the isotonic sodium chloride solution group (4 [33.3%] of 12), the chlorhexdine group (4 [33.3%] of 12), the intraperitoneal methotrexate group (2 [16.7%] of 12), and the parenteral methotrexate group (5 [41.7%] of 12). Conclusions: The results of this study suggest that the development of metastases to port sites following laparoscopic surgery may be prevented by the intraperitoneal instillation of diluted povodine-iodine. Other agents failed to influence the incidence of port-site metastases. Further studies are needed to determine if these findings can be applied to humans.