Tumour implantation following laparoscopy using different insufflation gases

Background: Because of the possibility of intraperitoneal seeding and port-site recurrences following laparoscopic surgery, the role of laparoscopy in cancer surgery remains controversial. Previous experimental studies have suggested that chemical, metabolic and immunological changes following carbon dioxide (CO2) insufflation may be responsible for this phenomenon. Earlier experimental studies done by the University of Adelaide Department of Surgery have also shown that helium insufflation is associated with none of the adverse changes brought about by CO2 insufflation. Helium insufflation is also associated with lower rates of intra-abdominal tumour spread. The aim of this study was to determine whether these identified benefits apply to inert gases in general. Methods: Twenty-four Dark Agouti rats were randomized to undergo laparoscopy with 40 min insufflation using one of the following four gases (six rats in each group); CO2, helium, argon and nitrogen. A tumour cell suspension was injected into the abdominal cavity at the beginning of laparoscopy. The rats were killed 7 days after surgery, and the peritoneal cavity and port sites were examined for the presence of tumour. Results: Rats undergoing helium insufflation, had the least number of port-site recurrences and the least amount of intraperitoneal tumour spread. Argon and nitrogen pneumoperitoneum were associated with a large number of port-site recurrences and widespread tumour seeding. The effect of CO2 insufflation was intermediate. Conclusion: The choice of insufflation gas influences the incidence of port-site metastases and the degree of intraperitoneal tumour spread following laparoscopic cancer surgery. The reduced port-site recurrences and intraperitoneal spread that followed helium pneumoperitoneum is likely to be a unique property of this gas rather than a property of inert gases in general.