Background. It was shown in a murine model that sham laparotomy is associated with a higher incidence of postoperative lung metastases when compared with results seen after carbon dioxide pneumoperitoneum. Using the same tumor model, the present study was undertaken to determine if the addition of bowel resection to the operative procedure would impact the results. Methods. Sixty mice underwent anesthesia alone (anesthesia control [AC]), laparoscopic-assisted cecectomy (LC), or open cecectomy (OC). After surgery, all animals received tail vein injections of 105 TA3-Ha tumor cells. On postoperative day 14, the lungs and trachea were excised en bloc and processed, and surface lung metastases were counted and recorded by a blinded observer. Results. The mean number of surface lung metastases in the AC, LC, and OC groups was 30.9, 76.3, and 134.5, respectively. Significantly more metastases were documented after OC (P < .001) and LC (P < .05) than after anesthesia alone. Mice in the LC group had significantly fewer lung metastases (43% less) than mice in the OC group (P < .01). Conclusions. OC was associated with significantly more lung metastases than either LC or AC. Surgery-related immune suppression or trophic tumor cell stimulation occurring after surgery may contribute to this phenomenon.
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