The impact of laparoscopy with carbon dioxide versus helium on immunologic function and tumor growth in a rat model

Background: The pathogenesis of port site recurrences after laparoscopic surgery for malignant disease is still unknown, Whether different gases used to establish pneumoperitoneum have an influence on immunologic function and therefore on promotion of tumor growth has not yet been investigated. Methods: Tumor growth of colon adenocarcinoma DHD/K12/TRb was evaluated in a rat model after insufflation either with CO2 (n = 25) or helium (n = 25) and in a control group (n = 25). Tumor growth was measured subcutaneously and intraperitoneally 5 weeks after insufflation. Beside tumor growth, immunologic changes (peripheral leukocyte subpopulations, plasma levels of TNF alpha and IL-10) were evaluated during the perioperative course in all animals. Results: Subcutaneous tumor growth was promoted by the CO2 (99 +/- 55 mg; p < 0.01) compared to the helium (40 +/- 41 mg) and control groups (36 +/- 33 mg). Total intraperitoneal tumor weight was 718 +/- 690 mg in the CO2 group compared to the helium (549 +/- 233 mg) and control groups (521 +/- 221 mg). While peripheral leukocyte subpopulations only differed between the laparoscopic groups and the control group during the perioperative course, TNF alpha plasma levels were significantly decreased and IL-10 plasma levels significantly increased in the CO2 group compared to the helium and control groups in the postoperative course. Conclusion: The insufflation of CO2 promotes tumor growth compared to the helium and control groups ill a rat model. In addition, increased tumor growth was associated with a significant increase in IL-10 and a decrease in TNF alpha plasma levels.