Grant: Op Gr: Data Analysis Using Existing Databases n Cohorts-Cancer Prevention n Ctrl

Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, are on the rise in Canada and worldwide. 1% of Canadians are expected to have IBD by 2030. Cancer is a highly feared complication of IBD and commonly influences diagnostic testing and treatment choice. The impact of biologic treatments on cancer risk in persons with IBD has not been well studied. By more effectively suppressing inflammation in the gut, these therapies could decrease the risk of gut-specific cancers, such as colorectal cancer (CRC). Conversely, by suppressing the immune system, these therapies could also increase the risk of other cancers, including lymphoma, skin cancers and cervical cancer. However, as most studies have assessed cancer risks prior to the widespread use of biologic therapies and other major treatment changes, newer data is required to better counsel patients and guide treatments and cancer screening practices. Across Canada, researchers have access to provincial health care data for all citizens, including all health care usage and major health outcomes. We will access and pool this data from five provinces (Ontario, Nova Scotia, Manitoba, Saskatchewan and Alberta) that can identify individuals with IBD and cancers at a population level to study national trends in IBD-relevant cancers and present-day cancer risks faced by persons with IBD, in comparison to persons from the general population. We will also statistically evaluate whether trends in cancer rates have changed over the past decade among persons with IBD, relative to historical trends, in conjunction with major changes to IBD treatment. We will leverage the resources and infrastructure of The Canadian Gastrointestinal Epidemiology Consortium (CanGIEC) to facilitate study conduct. Ultimately, our study will provide the most current and precise estimates of cancer risks faced by persons with IBD and their relationships to current IBD treatments in the Western World.