Validity of current experimental evidence on laparoscopic surgery for colorectal cancer.

Experimental animal studies can provide crucial evidence for the evaluation and refinement of the controversial area of many areas of surgery. Recently, during the surge in interest in laparoscopic surgery, in particular for colorectal cancer, 72 animal studies have been published between 1995 and 2001. However, the question remains as to which of theses data can be suitably extrapolated to the human population. Forty-five of 47 studies, which use cell suspensions, relied on percutaneous intraperitoneal injection of cancer cells to induce peritoneal carcinomatosis. One study described a laparotomy-based model with injection of tumor cells into the cecal lumen while a different study presented the cancer cells via enema. In this study, sigmoid resection was performed before colorectal solid tumor growth.