IBD and Cancer
People with IBD are at a greater risk of developing certain types of cancer compared to the general population. This is largely due to the chronic intestinal inflammation inherent to IBD. A person’s exposure to intestinal inflammation generally increases with the time since diagnosis, and as such, older individuals are more likely to experience inflammation-related cancers.
Cancers associated with chronic intestinal inflammation include colorectal cancer, small bowel adenocarcinoma, intestinal lymphoma and anal cancer. Beyond the cancer risk of chronic inflammation, the immunosuppressive nature of drugs used to treat IBD (e.g., thiopurines, methotrexate)may also increase the risks of cancers such as non-Hodgkin lymphoma.
Risk factors for developing cancer include:
- A diagnosis of IBD that is limited to inflammation of the colon. This includes ulcerative colitis and the colon-only Crohn’s colitis.
- Presence of primary sclerosing cholangitis (PSC; an inflammatory condition involving the liver and gallbladder).
- Family history of colorectal cancers
- Previous dysplasia (abnormal cells that precede the development of cancerous cells).
- An 8-10 year history of IBD
- Folate deficiency
Protective factors (i.e., factors associated with a reduced risk of developing IBD-related cancers) include:
- Proper surveillance (i.e., monitoring for the abnormalities at regular intervals through colonoscopy and biopsies)
- Adhering to treatment (i.e., following the treatment for your IBD as intended)
- Healthy living habits (e.g., healthy eating, regular exercise).
- Use of folic acid
- Use of 5-aminosalicylic acid (i.e., Mesalazine)
How can I reduce my risk?
Taking medications as intended can reduce instances of avoidable inflammation, and in turn, the risk of inflammation-related cancers. Depending on your level of risk, your doctor may determine that regular surveillance is required. This typically involves chromoendoscopy (colonoscopy using dye to enhance visualisation of the bowel) every 1-3 years to inspect the bowel and monitor for any abnormalities indicating a potential cancer risk. Adopting habits of healthy eating and regular exercise may also reduce the risk of IBD-related cancers.