Pancreatobiliary diversion enhances experimental pancreatic carcinogenesis.

Since compensatory hyperplasia promotes experimental carcinogenesis in the gut, we tested the ability of two surgical models of pancreatic growth to promote pancreatic carcinogenesis. Male Wistar rats (n = 60) weighing 250-300 g underwent pancreatobiliary diversion (PBD), 90% small bowel resection (PSBR) or triple transection and reanastomosis of the small intestine (controls). Postoperatively, each group received azaserine (20 mg kg-1 wk-1 i.p.) for 6 weeks. Surviving rats were killed at 6 months, pancreatic wet weight was measured and histological sections were examined for atypical acinar cell foci (AACF), the putative precursor of carcinoma. Median relative pancreatic weight (mg pancreas/g body weight) was 2.20 for controls (n = 18), 4.08 for PSBR (n = 11) (P less than 0.001) and 6.86 for PBD (n = 16) (P less than 0.001). PSBR did not affect the development of acidophilic AACF, but PBD produced an enormous increase in their number per cm3 (median 96 vs. 0; P less than 0.001) and a 7-fold increase in their volume (P less than 0.001). Both operations cause pancreatic growth, but only PBD promotes carcinogenesis, possibly because of its unique hormonal effect.