Nationwide survey of pancreaticobiliary maljunction focusing on biliary cancer incidence in Japan.

Abstract

587 Background: Pancreaticobiliary maljunction (PBM) is known to be a unique entity closely related to biliary carcinogenesis. We herein report update analysis of PBM focusing on biliary cancer as third report of Japan-nationwide survey. Methods: From 1990 to 2015, 3,419 patients with PBM were registered at 141 medical institutions in Japan. 3,289 (1,344 pediatric and 1,945 adult patients) out of 3,419 patients were fully investigated, according to presence of bile duct dilatation (BDD), age (pediatric or adult), etc. Results: In pediatric patients, only 3 cases with BDD (0.124%) had bile duct cancers. On the other hand, in adults, biliary cancer incidence was 21.1% in patients with BDD and 43.5% in patients without BDD. The rates were extremely high in comparison with 0.0174% of Japanese prevalence of biliary cancer 2013. The cancer incidences of bile duct, gallbladder and both in adults with BDD/without BDD were 6.7%/4.1%, 13.0%/37.3%, and 1.4%/2.1%, respectively. In patients without associated biliary cancers, extrahepatic bile duct resection (EHBDRx) combined with cholecystectomy was performed in 89.5% of adults with BDD, while, in only 31.2% adults without BDD. Regarding the new biliary cancer occurrence of patients having follow-up data, the rate was 0.3% in 354 patients with BDD who underwent EHBDRx, while that was 4.0% in 75 patients without BDD who underwent simple cholecystectomy. In patients without BDD, cancer incidence (6.7%) in the late period (2010 to 2015) was higher than those (3.3% and 3.5%) in early and middle period (1990 to 1999, and 2000 to 2009). Conclusions: This updated nationwide survey of PBM revealed characteristics of associated and newly occurred biliary cancers, and could be widely used as a reference data for diagnosis and treatment of PBM.