Background: Pancreatobiliary reflux (PBR) can occur in individuals without pancreaticobiliary maljunction. The aim of this study was to elucidate the incidence of PBR in individuals with a normal pancreaticobiliary junction and its impact on the biliary tree.
Methods: Data were prospectively collected from 15 centers on 420 patients with a morphologically normal pancreaticobiliary junction who had undergone bile sampling and measurement of the biliary amylase level. We investigated the incidence and predictive factors for high biliary amylase levels (HBAL), as well as the relationship of HBAL with biliary malignancy.
Results: Twenty-three patients (5.5%) showed HBAL (≥10,000 IU/L). Univariate analysis showed that risk factors for the elevation of biliary amylase levels were the existence of a relatively long common channel (≥5 mm), acute pancreatitis, and papillitis. Multivariate analysis revealed that only the existence of a relatively long common channel was a significant factor for PBR. Biliary amylase levels in patients with a relatively long common channel were significantly higher than in patients without a long common channel (12,333 vs. 2,070 IU/L, P = 0.001). The incidence of HBAL (P < 0.001), as well as the overall biliary amylase levels (P = 0.007) were significantly higher in patients with gallbladder cancer than in those without gallbladder cancer.
Conclusions: The PBR was frequently observed in individuals with a relatively long common channel. Patients showing HBAL with normal pancreaticobiliary junction are at high risk for gallbladder cancer.