Familial adenomatous polyposis predisposes to pathologic exposure of the stomach to bilirubin

The role of duodenogastric reflux in the genesis of gastric polyps in familial adenomatous polyposis (FAP), although suggested by scintigraphy scanning studies, remains unclear.

Twenty-four hour intragastric bilirubin monitoring with the Bilitec optoelectronic device was carried out in 25 FAP patients, of whom 19 had gastric polyps (fundic gland in 13, adenomatous in 2, and both histologic types in 4) on endoscopic examination. Gastric exposure to bilirubin was expressed as the percentage of total recording time that absorbance exceeded the threshold of 0.25 and was calculated in reference to values obtained from 25 healthy volunteers. Helicobacter pylori status of the stomach was checked as well.

Gastric exposure to bilirubin was pathologic in 14 (56%) patients. Gastric exposure to bilirubin was of longer duration in FAP patients than in healthy volunteers (mean+/-SEM: 19%+/-4% vs 6%+/-2%) (P<.005). It increased from healthy volunteers (6%+/-2%) to FAP patients without gastric polyps (10%+/-3%), and to FAP patients with gastric polyps (22%+/-5%) (P<.004). Bilirubin exposure times were similar in FAP patients with fundic gland polyps only and in those having either adenomatous polyps only or both types of polyps (24%+/-7% vs 17%+/-4%). No patient with pathologic gastric exposure to bilirubin as well as none having gastric polyps, had H. pylori in the antrum.

This study shows that gastric exposure to bilirubin is of longer duration in FAP patients than in healthy volunteers, and in FAP patients with gastric polyps than in those without polyps. This study supports the existence of a direct correlation between pathologic duodenogastric reflux (DGR), the absence of H. pylori in the antrum, and the presence of gastric polyps in FAP patients.