Pneumoperitoneum with carbon dioxide stimulates growth of malignant colonic cells

Background. Port-site recurrences have often been reported after laparoscopic surgery for malignant disease, and the pathogenesis is unknown. Whether different gases used to establish pneumoperitoneum have an influence on tumor cell growth has not been investigated. Methods. Tumor growth of colon adenocarcinoma DHD/K12/TRb was measured in a rat model after insufflation with either carbon dioxide or helium and in a control group. Tumor growth was evaluated in three experiments: (1) in vitro (n = 60), (2) ex vivo (n = 60), and (3) in vivo (n = 60). After insufflation, cell kinetics were determined in the first two experiments. In the third experiment, tumor growth was measured subcutaneously and intraperitoneally 5 weeks after insufflation. Results. Tumor cell growth increased significantly after insufflation with carbon dioxide in vitro (p < 0.03) and ex vivo (p < 0.05) compared with the control group, whereas helium did not stimulate cell growth. In vivo, subcutaneous tumor growth was promoted by carbon dioxide (131 +/- 55 mg) (p < 0.01) compared with helium (35 +/- 34 mg) and the control group (36 +/- 33 mg). Total intraperitoneal tumor weight was 717 +/- 320 mg in carbon dioxide group, compared with helium (549 +/- 231 mg) and control group (570 +/- 321 mg). Conclusions. The insufflation of carbon dioxide promotes tumor growth compared with helium and control in a rat model. Further studies should confirm these results before alternative gases should be recommended in laparoscopic surgery for malignant diseases.