Tumor growth and dissemination after laparotomy and CO2 pneumoperitoneum: a rat ovarian cancer model.

OBJECTIVE

To compare tumor growth, intraperitoneal implantation, and abdominal wall metastasis after laparotomy and CO2 pneumoperitoneum in a rat ovarian cancer model.

METHODS

To mimic intraoperative rupture of an ovarian tumor in a syngenic rat ovarian carcinoma model, 10(5) malignant cells were injected intraperitoneally after a 5-cm vertical midline laparotomy or after the insufflation of a CO2 pneumoperitoneum achieved with 4 mmHg or 10 mmHg intra-abdominal pressure. Two weeks later, the intraperitoneal tumor growth and the tumor dissemination were evaluated semiquantitatively with a scoring system. The scores attributed to each organ were added to calculate the dissemination score of each animal.

RESULTS

The mean (+/-SD) dissemination score was 83.4+/-12 in the laparotomy group and 67.3+/-16 and 71.9+/-17 in the 4 and 10 mmHg CO2 pneumoperitoneum groups, respectively (P < .01). The scores for the peritoneum were 21.8+/-3.8 in the 10 mmHg pneumoperitoneum group and 18+/-2.4 in the laparotomy group (P < .01). In the laparotomy group, the implant found along the midline scar accounted for a mean of 62.6+/-15% of the peritoneal score, whereas the trocar site metastases did not influence the peritoneal score in the pneumoperitoneum groups. The incidence of wound metastasis was 96% in the laparotomy group and 55% and 54% in the 4 mmHg and 10 mmHg pneumoperitoneum groups, respectively.

CONCLUSION

In this model, tumor growth was greater after laparotomy than after laparoscopy, but peritoneal tumor dissemination was more severe after CO2 pneumoperitoneum.