Prevention of cancer in IBD - a balancing act.

Inflammation and immunosuppression are two major risk factors for the development of carcinogenesis in inflammatory bowel disease (IBD). While the natural history of uncontrolled inflammation in the bowel may lead to a higher incidence of colorectal cancer (CRC), surveillance colonoscopy has resulted in earlier detection of dysplasia and cancer, prompting earlier surgical intervention and improved prognosis, while chemoprevention in the form of the anti-inflammatory 5-aminosalicylate acids and immunosuppression could potentially decrease the incidence of CRC. Numerous extra-intestinal cancers such as hepatobiliary and pancreatic malignancies, however, are also noted to be more prevalent in IBD patients particularly with co-existing primary sclerosing cholangitis. Somewhat ironically, however, the medications used to control the inflammation in IBD may also be responsible for the development of other cancers. The increased risk of lymphoma and skin cancers associated with immunosuppressive medication use may potentially be due to loss of immunosurveillance and in the case of lymphoma, the presence of oncogenic viruses (i.e., Epstein-Barr virus). Thus the challenge for both the treating physician and IBD patient is to balance the risk of any potential treatment against patient symptoms and the natural history of uncontrolled inflammation from their disease.