Meta-analysis: Risk of pancreatic cancer in patients with inflammatory bowel disease

Background: Studies exploring the association between inflammatory bowel disease (IBD) and pancreatic cancer have reported inconsistent results. Aims: To provide a comprehensive overview of the risk of pancreatic cancer development in patients with IBD. Methods: We searched Embase, PubMed, Scopus and ProQuest from inception to 31 October 2023. We included population-based cohort studies examining the risk of incident pancreatic cancer in adult patients with IBD compared to the non-IBD population. We also retrieved Mendelian randomisation (MR) studies investigating the relationship of IBD with pancreatic cancer risk. We conducted random-effects meta-analyses and provided pooled relative risks (RRs) with 95% confidence intervals (CIs). Results: We included 13 studies. Among 11 cohort studies, the risk of developing pancreatic cancer increased by 79% in patients with IBD (RR = 1.79 [95% CI: 1.16–2.75]; I² = 95.7%). Patients either with Crohn's disease (RR = 1.42 [95% CI: 1.24–1.63]) or ulcerative colitis (RR = 1.50 [95% CI: 1.17–1.92]) had increased risk (p for interaction = 0.72). The annual incidence of pancreatic cancer potentially attributable to IBD increased by 55 cases (95% CI: 17–103) per million. Two MR studies demonstrated that genetic liability to IBD was associated with an increased risk of pancreatic cancer. Conclusions: Our results suggest a moderate increase in the risk of pancreatic cancer in patients with IBD, which may be further heightened by genetic predisposition to IBD. The increased risk of pancreatic cancer is probably similar in Crohn's disease and ulcerative colitis.