Pneumoperitoneum with carbon dioxide enhances liver metastases of cancer cells implanted into the portal vein in rabbits

Background: Little is known about the role of the CO2 pneumoperitoneum on t umor cells that spread from the portal system into the Liver during laparos copic surgery for gastrointestinal malignancies. Therefore, we designed a s tudy to investigate the effect of CO2 pneumoperitoneum on cancer cells impl anted in the portal vein in a rabbit model. Methods: Immediately after intraportal inoculation of 2.5 x 10(5) cells of VX2 cancer, the rabbits received either CO2 pneumoperitoneum at a pressure of 10 mmHg for 30 min (pneumoperitoneum group, n = 14) or laparotomy alone for 30 min (laparotomy group, n = 14), Results: The number (p < 0.01) and area of cancer nodules (p = 0.045) on th e liver surface on day 17 were greater in the pneumoperitoneum group than i n the laparotomy group. The frequency of cancer nodules >3.0 mm in diameter was higher in the pneumoperitoneum group than in the laparotomy group (p < 0.001), Conclusions: Compared with laparotomy, CO2 pneumoperitoneum enhanced the de velopment of liver metastases in this experimental model.