A Population-Based Matched Cohort Study of Digestive System Cancer Incidence and Mortality in Individuals With and Without Inflammatory Bowel Disease.

Introduction: To study digestive system cancer risks in individuals with inflammatory bowel diseases (IBDs) in the biologic era.

Methods: We used population-level administrative and cancer registry data from Ontario, Canada, (1994-2020) to compare people with IBD to matched controls (1:10 by sex and birth year) on trends in age-sex standardized cancer incidence and risk ratios of incident cancers and cancer-related deaths.

Results: Among 110,919 people with IBD and 1,109,190 controls, colorectal cancer incidence (per 100,000 person-years) declined similarly in people with ulcerative colitis (average annual percentage change [AAPC] -1.81; 95% confidence interval [CI] -2.48 to -1.156) and controls (AAPC -2.79; 95% CI -3.44 to -2.14), while small bowel cancer incidence rose faster in those with Crohn's disease (AAPC 9.68; 95% CI 2.51-17.3) than controls (AAPC 3.64; 95% CI 1.52-5.80). Extraintestinal digestive cancer incidence rose faster in people with IBD (AAPC 3.27; 95% CI 1.83-4.73) than controls (AAPC -1.87; 95% CI -2.33 to -1.42), particularly for liver (IBD AAPC 8.48; 95% CI 4.11-13.1) and bile duct (IBD AAPC 7.22; 95% CI 3.74-10.8) cancers. Beyond 2010, the incidences (and respective mortality rates) of colorectal (1.60; 95% CI 1.46-1.75), small bowel (4.10; 95% CI 3.37-4.99), bile duct (2.33; 95% CI 1.96-2.77), and pancreatic (1.19; 95% CI 1.00-1.40) cancers were higher in people with IBD.

Discussion: Cancer incidence is declining for colorectal cancer and rising for other digestive cancers in people with IBD. Incidence and mortality remain higher in people with IBD than controls for colorectal, small bowel, bile duct, and pancreatic cancers.