S45 Cancers Associated With Inflammatory Bowel Disease: A Population-Based Case-Control Study

Abstract

Background: Individuals with inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are known to have a higher risk of digestive tract cancers as compared to the general population. As the IBD population has gotten older over time, age-related cancers may be more commonly diagnosed. We conducted a population-based study to assess whether incident cancers were being diagnosed more commonly overtime and whether those with IBD were more likely to be diagnosed with cancer. Methods: A population-based surveillance case-control study was conducted in in Alberta, Canada from April 1, 2002 to March 31, 2018. A validated coding algorithm identified all cases of IBD stratified by type of IBD (CD, UC). Each case was age and sex matched to 10 non-IBD cases from the general population, and then linked to the Alberta provincial cancer registry to extract pathology-confirmed incident cancer. Cancer diagnoses were classified: colorectal, small bowel, pancreatic, biliary and liver, breast, cervical, endometrial, thyroid, hematological, lung, neurological, melanoma, non-melanoma skin cancer, prostate, renal, and bladder. Odds ratios (OR), with 95% confidence intervals (CI), compared IBD cases to matched controls using conditional logistic regression. The annual incidence of cancer diagnosis among the at-risk prevalent IBD population was determined with the average annual percentage change (AAPC) calculated using log binomial regression. Results: Overall, 3,695 incident cancers were diagnosed among 35,763 individuals with IBD as compared to 31,365 cancers among 362,248 controls (IBD: OR = 1.22; 95% CI: 1.18, 1.27; CD: OR = 1.42, 95% CI: 1.34, 1.49; UC: OR = 1.13 95% CI: 1.06, 1.20). Annual incident cancers in those with IBD steadily increased by 3.4% per year (AAPC = 3.44%; 95% CI: 2.71%, 4.18%). A higher odds of cancer was observed across digestive tract cancers for those with IBD: biliary and liver (IBD: OR = 7.76; 95% CI: 5.89, 10.22); colorectal cancer (IBD: OR = 1.88; 95% CI: 1.67, 2.15); small bowel (CD: OR = 10.81; 95% CI: 6.89, 16.95; UC: OR = 1.74; 0.73, 4.16); and pancreas (IBD: OR = 8.01; 95% CI: 5.72, 11.20). Outside of the digestive tract the following cancers were more common in those in IBD: hematological (IBD: OR = 1.47, 95% CI: 1.29, 1.67); lung (IBD: OR = 4.16; 95% CI: 3.59, 4.81); neurological (IBD: OR = 4.73; 95% CI: 3.12, 7.18; and renal (IBD: OR = 2.18; 95% CI: 1.77, 2.68). Non-melanoma skin cancers were associated with IBD (OR = 1.11; 95% CI: 1.05, 1.18), but not melanoma (OR = 0.98; 95% CI: 0.82, 1.18). Other solid-organ cancers were not associated or occurred less commonly in those with IBD: prostate (OR = 0.68; 95% CI: 0.60, 0.77); bladder (OR = 0.73; 95% CI: 0.57, 0.92), cervix (OR = 0.83; 95% CI: 0.73, 0.93), endometrium (OR = 0.50; 95% CI: 0.36, 0.70), and thyroid (OR = 0.84; 95% CI: 0.65, 1.10). Conclusion(s): Over time, persons with IBD are being more commonly diagnosed with cancer. Individuals with IBD are more likely to be diagnosed with cancer as compared to the general population with cancers of the digestive tract driving this association. Healthcare providers should be aware of higher occurrence of hematological, neurological, lung and renal cancers in those with IBD.