Difficult biliary cannulation during endoscopic retrograde cholangiopancreatography for distal malignant biliary obstruction caused by pancreatic cancer: An observational study

Distal malignant biliary obstruction (DMBO) caused by pancreatic cancer often complicates endoscopic retrograde cholangiopancreatography (ERCP), particularly biliary cannulation. While various factors influencing difficult biliary cannulation (DBC) have been studied, data specific to pancreatic cancer-related distant malignant biliary obstruction#x000A0;remains limited. This study identifies factors affecting ERCP success in this patient population to improve clinical outcomes. We retrospectively analyzed 119 ERCP procedures for distant malignant biliary obstruction owing to pancreatic cancer with naïve papilla at Showa University Fujigaoka Hospital (January 2020-September 2024). Patient characteristics, duodenal invasion, ampullary bile duct status, papillary morphology, trainee involvement, and adverse events were evaluated. Multivariate analysis identified predictive factors of DBC. After excluding 17 ERCP failures, 102 patients were analyzed and categorized into non-DBC (n = 40) and DBC (n = 62) groups. The DBC incidence rate was 60.8%. The absence of the ampullary bile duct (odds ratio [OR]: 2.58, 95% confidence interval [CI]: 1.02-6.51; p = 0.04) and the macroscopic appearance of type III papillary morphology (enlarged/protruding; OR: 3.32; 95% CI: 1.07-10.30; p = 0.04) were significantly associated with DBC. Adverse events were slightly more frequent in the DBC group; however, this difference was not statistically significant. Alternative cannulation was performed more often in patients without the ampullary bile duct; however, no difference in adverse events was observed. The absence of the ampullary bile duct and type III papillary morphology are anatomical risk factors for DBC during ERCP for patients with pancreatic cancer. Early consideration of alternative cannulation techniques or biliary drainage methods may be necessary for such patients.