The effect of immune enhancement and suppression on the development of laparoscopic port site metastases

Background: Recent clinical case reports and experimental studies have sugg ested that laparoscopic cancer surgery is associated with an increased risk of tumor spread to abdominal wall wounds. While the etiology of this probl em was initially believed to be related to mechanical contamination of woun ds, it is now recognized that there are other contributory factors, includi ng disturbed immune function within the peritoneal cavity. To investigate t his question further, we evaluated the effect of immune modulation within a n established laparoscopic cancer model. Methods: Eighteen immune-competent syngeneic rats underwent modulation of t heir immune system, followed 18 h later by laparoscopy with the introductio n of a suspension of adenocarcinoma cells into the peritoneal cavity. Rats were randomly allocated to receive either systemic cyclosporin (immune supp resser), intraperitoneal endotoxin (immune enhancer), or no agent (controls ). Seven days later, all rats were killed and their peritoneal cavity was i nspected for tumor implantation and port site metastases. Results: Cyclosporin did not influence the study outcome, but tumor growth (p = 0.008) and port site metastases (p < 0.0001) were less common followin g the administration of: intraperitoneal endotoxin. Conclusion: The results of this study suggest that the immune system plays a role in the genesis of port site metastases. A preventive role for endoto xin in patients undergoing laparoscopic cancer surgery, however, remains sp eculative.