Peritoneal irrigation with povidone-iodine solution after laparoscopic-assisted splenectomy significantly decreases port-tumor recurrence in a murine model

PURPOSE: The development of port-wound tumor recurrences has raised questions regarding the safety of laparoscopic methods for the resection of malignancies. The cause and the incidence of abdominal-wall tumor recurrences remain unknown. It is also not clear how to avoid or lower the incidence of port-tumor recurrences. The purpose of the current study was to determine the impact of abdominal irrigation with povidone-iodine on the port-wound tumor incidence in a murine model. METHODS: A splenic tumor model was used for this study. To establish splenic tumors, female BALB/c mice (N = 48) were given subcapsular splenic injections of a 0.1 ml suspension containing 10(5) C-26 colon adenocarcinoma cells via a left-flank incision at the initial procedure. Seven days later, the animals with isolated splenic tumors (100 percent) were randomly assigned to one of three groups: 1) control, 2) saline irrigation (saline), or 3) povidone-iodine irrigation. All animals underwent laparoscopic mobilization of the spleen using a three-port technique, intra-abdominal crushing of the tumor, followed by an extracorporeal splenectomy via a subcostal incision. No irrigation was performed for control group animals. In the saline irrigation group, the subcostal incision was closed and pneumoperitoneum was reestablished. The abdominal cavity was irrigated with 5 ml of normal saline for 60 seconds before instrument removal. In the povidone-iodine irrigation group, similar abdominal irrigation was performed, using 0.25 percent povidone-iodine. Attempts were made to recover completely the irrigation for both irrigation groups. Seven days after the splenectomy, animals were killed and inspected for abdominal-wall tumor implants. RESULTS: There were significantly more animals with at least one port-tumor recurrence in the control group than in the povidone-iodine group (P = 0.007). Although not statistically significant, the number of animal with port-wound tumors was higher in the saline group than in the povidone-iodine group (P < 0.08). There was no significant difference between the saline group and the control group. When each port site was considered independently, the incidence of port-wound tumors (number of ports with tumors per total number of ports) was significantly lower in the povidone-iodine group than in both the control (P = 0.00001) and saline groups (P = 0.03). The incidence of port-wound tumors was also significantly lower in the saline group compared with the control group incidence (P = 0.03). CONCLUSIONS: Abdominal irrigation with dilute povidone-iodine solution significantly reduced the number of animals with port-tumor recurrences. Abdominal irrigation with saline was also effective in reducing the incidence of port-wound tumor formation when each port was considered separately. However, povidone-iodine irrigation was much more effective than saline irrigation in preventing port-wound tumor formation.