Risk of cancer in inflammatory bowel disease (IBD)

Patients with inflammmatory bowel disease (IBD) have been reported to have an increased risk of colorectal cancer. Yet, the quantitation of the risk varies widely from one study to the next. This is most likely due to biases in the assessment of cancer risk in IBD, namely, a relatively low prevalence of IBD-related cancer and the clinically heterogeneous nature of IBD in the population. Total proctocolectomy also changes the natural history of IBD-related cancer. Ulcerative colitis (UC)-related cancer is more probable in total and extensive colitis and occurs approximately a decade after diagnosis. Crohn's disease-related colorectal cancer is reported in many, but not all, studies, and the relative risk differs between hospital- and population-based studies. IBD-related cancer is relatively uncommon in childhood; however, this is also a subject of debate. There are no data on the incidence of IBD-related cancer in Europe as a whole; there are only separate studies. A reduced risk for UC-related cancer in patients treated with anti-inflammatory drugs has been reported. The two main strategies for preventing IBD-related cancer are prophylactic colectomy and colonoscopic surveillance. To date, there have virtually been no cost-effectiveness analyses and no studies regarding total disease outcome or patient's quality of life with either strategy. No controlled, prospective trials have been reported in the literature. UC patients with familiar predisposition for colorectal cancer and with concomitant primary sclerosing cholangitis are groups at high risk for IBD-related cancer. Cancer risk in IBD has to be reinvestigated and properly estimated with population-based studies in several areas with standard methods already described.