The effect of CO2 pneumoperitoneum on the growth of a solid colon carcinoma in rats

Background: In order to investigate the effect of carbon dioxide (CO2) pneumoperitoneum on solid colon carcinomas, we used a colon anastomosis tumor model in 30 male syngeneic WAG rats, which were divided, at random into three groups. Methods: In all rats, 10(6) CC531 S colon carcinoma cells were injected as an enema into the colon. Subsequently, a transection and a reanastomosis of the colon descendens was performed via laparotomy. After 2 weeks, group 1 (n = 10) was anesthetized as an anesthesia control group. Group 2 (n = 10) had a laparotomy that was closed after 20 min. In group 3 (n = 10), a CO2 pneumoperitoneum of less than or equal to 6 mmHg was created and maintained during 20 min. After 2 weeks, all rats were killed, and total tumor weight and volume was measured. Results: At necroscopy tumor growth was found in 16 rats (group 1: six; group 2: five; group 3: five). No difference in tumor growth (weight or volume) was found between the three groups. Conclusion: In our solid colon carcinoma model, CO2 pneumoperitoneum did not enhance tumor growth.