TUMOR-GROWTH AFTER LAPAROTOMY OR LAPAROSCOPY - A PRELIMINARY-STUDY

We investigated the effects of laparotomy and insufflation on tumor es tablishment and growth in a murine model. Twenty female mice received intradermal inoculation of a low dose of tumor cells (2 x 10(3)) deriv ed from the MC2 mouse mammary carcinoma cell line. Ten of these mice u nderwent laparotomy and ten received intraperitoneal insufflation with carbon dioxide gass at a pressure of 5 mmHg for 30 min. Tumor growth was followed postoperatively. By post-operative day 14, tumors had gro wn in zero of the ten insufflated mice and in seven of the ten laparot omy-group mice (P < 0.005). By postoperative day 30, tumors had grown in one of the ten insufflated mice and in eight of the ten laparotomy- group mice (P < 0.007). Ten additional mice received a high-dose inocu lum of cells (1 x 10(6)) followed by either laparotomy or intraperiton eal insufflation. Upon sacrifice 12 days later, all mice had developed tumors, but the laparotomy group's tumors were almost three times as large, by mass, as tumors in the insufflated group (70.5 +/- 23.5 mg v s 25.8 +/- 9.5 mg; P < 0.02). These results suggest that laparotomy co nfers a permissive effect on tumor establishment and growth in a murin e model not seen after peritoneal insufflation. We hypothesize that th is may be a function of relative immunosuppression following laparotom y which is not present following peritoneal insufflation. These data m ay be important when choosing a route of access to the peritoneal cavi ty for cancer resection.