Effect of major small bowel resection on dimethylhydrazine-induced bowel carcinogenesis.

We have investigated the effect of distal small bowel resection on chemically induced tumors of the gastrointestinal tract in Wistar/Furth (W/Fu) rats. Dimethylhydrazine (DMH) (20 mg/kg sc once weekly x 16) was commenced 3 months after rats underwent resection of the distal 30 cm of small bowel (one-third resection) or after sham small bowel resection (controls). Fifty weeks after the start of DMH administration, tumors were found in 15 of 25 animals who underwent small bowel resection compared to 9 of 31 animals in the control group (P less than 0.05). After small bowel resection, 8 of 15 tumors occurred at the site of anastomosis but no anastomotic tumors were seen after sham resection. In addition, tumors were larger and more invasive after small bowel resection. These data indicate that major small bowel resection potentiates DMH induced-intestinal carcinogenesis.