Inflammatory Bowel Disease and Risk of Cholangiocarcinoma: Evidence from a Meta-analysis of Population-based Studies

Objective: Patients with inflammatory bowel disease (IBD) have an increased risk of extra-intestinal cancer,whereas its impact on cholangiocarcinoma (CC) remains unknown. The aim of this study was to obtain a reliableestimate of the risk of CC in IBD patients through a meta-analysis of clinical observational studies.
Methods:Relevant studies were retrieved by searching PUBMED, EMBASE and Web of Science Databases up to Dec2013. Four population-based case-control and two cohort studies with IBD were identified. Summary relativerisk (RR) and its corresponding 95% confidence interval (CI) were calculated using a random-effects model.Potential sources of heterogeneity were detected using subgroup analyses.
Results: The pooled risk estimateindicated IBD patients were at increased risk of CC (RR = 2.63, 95%CI = 1.47-4.72). Moreover, the increasedrisk of CC was also associated with Crohn’s disease (RR = 2.69, 95%CI = 1.59-4.55) and ulcerative colitis (RR =3.40, 95%CI = 2.50-4.62). In addition, site-specific analyses revealed that IBD patients had an increased risk ofintrahepatic CC (ICC) (RR = 2.61, 95%CI = 1.72-3.95) and extrahepatic CC (ECC) (RR = 1.47, 95%CI = 1.10-1.97).
Conclusions: This study suggests the risk of CC is significantly increased among IBD patients, especiallyin ICC cases. Further studies are warranted to enable definite conclusions to be drawn.