THE RISK OF CHOLANGIOCARCINOMA AFTER ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY WITH SPHINCTEROTOMY: A RETROSPECTIVE COHORT STUDY

Background: Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopic procedure utilized to diagnose and treat disorders of the pancreaticobiliary tract. Endoscopic sphincterotomy (ES) is performed using a small catheter with an electrocautery wire to cut through the sphincter of Oddi (SOD) to facilitate access to the bile and/or pancreatic duct. ERCP with ES results in irreversible SOD incompetence and allows for gut bacteria to reflux into the biliary tract. It has been hypothesized that these patients are at higher risks of chronic inflammation and infection of the bile duct, which may lead to higher rates of all-cause mortality, infection, and malignancy^3–6.
Aims: The primary aim of the study is to assess whether patients who have undergone endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy (ES) are at increased risk of cholangiocarcinoma compared to patients who have not undergone ERCP with ES. This study hypothesizes that ERCP with ES will increase the risk of developing cholangiocarcinoma due to the introduction of bacteria into the biliary tree, predisposing patients to the risk of long-term inflammation.
Methods: All patients undergoing ERCP in Manitoba, Canada from 1984-2018 were eligible for inclusion. Administrative data was extracted from the Manitoba Center for Health Policy, a population based administrative data registry, and cross-referenced with the Cancer Care Manitoba registry. Incidence cancers of the extra-hepatic and intrahepatic bile duct were analyzed. Gall bladder cancers, pancreatic cancers and ampullary cancers were excluded. Comparison of the risk of developing cholangiocarcinoma between those who underwent ERCP with ES and those who underwent ERCP without ES were made. Adjustments were made for age, sex, date of procedure, diabetes, inflammatory bowel disease (IBD) and cirrhosis. Hazard ratios were reported with 95% confidence intervals (CI).

Results: Of 23,262 patients undergoing ERCP included in the study, 257 cholangiocarcinomas were diagnosed. After excluding those diagnosed within 6 months of index procedure, 61 bile duct cancers remained. There was a statistically significantly increased risk of developing cholangiocarcinoma in the ERCP with ES group as compared to the ERCP without ES group, which held at 6 mos (HR 6.5, 95% CI 2.7-15.6), 1 year (HR 4.8, 95% CI 1.9-12.1) and 2 years (HR 5.75, 95% CI 2.4-13.9) post-ERCP, after adjusting for age, sex, year of ERCP, cirrhosis, diabetes and IBD.

Conclusion: ERCP with ES may increase the risk of developing cholangiocarcinoma. Further analysis is ongoing to determine the effect gallstone related disease may have on the risk of cholangiocarcinoma through a matched cholecystectomy cohort.