Increased Tumor Establishment and Growth After Laparotomy vs Laparoscopy in a Murine Model

To test our hypothesis that tumors would be more easily established and grow more aggressively after laparotomy than after laparoscopy. This hypothesis was based on studies that have demonstrated that surgery can suppress immune function and facilitate tumor growth and that have shown preservation of immune function after laparoscopic procedures. Double-blinded, randomized, control trial. Research laboratory and animal care facility. One hundred forty 5- to 6-week-old C3H/He female mice. Three experiments with three groups each: laparotomy, insufflation, and anesthesia controls. All animals received an intradermal inoculation of tumor cells in the dorsal skin. The anesthesia control cohort underwent no procedure. The laparotomy cohort underwent a midline laparotomy from the xiphoid process to the pubis, which was closed after 30 minutes. The insufflation cohort underwent peritoneal insufflation with carbon dioxide for 30 minutes. Tumor volume, tumor mass, and incidence of tumor establishment. In the first experiment, the tumor volumes of the anesthesia control and insufflation groups followed a similar pattern of plateau and regression. The tumor volumes of the laparotomy group followed a different pattern and were significantly larger than those of the control and insufflation groups on postoperative days 6 and 12 (P<.05 for all comparisons). In the second experiment, tumors in the laparotomy group were approximately three times larger than those of the control group (P<.01) and almost twice as large as insufflation group tumors (P<.01) by mass. In the third experiment, there was a significantly higher incidence of tumor establishment in the laparotomy group than in the insufflation (P<.04) or control (P<.01) groups. The incidence was not different between the control and insufflation groups. Tumors were more easily established and grew more aggressively after laparotomy than after insufflation. These results, coupled with those that demonstrate an immune advantage to laparoscopy over laparotomy, suggest that the difference in observed tumor growth may be related to immune function. While much work remains to be done, we believe these data provide evidence of a previously undemonstrated benefit of laparoscopic intervention.