Colorectal cancer in patients with inflammatory bowel disease: can we predict risk?

The inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), may be complicated by colorectal cancer (CRC). In a recent population-based cohort study of 47 347 Danish patients with IBD by Tine Jess and colleagues 268 patients with UC and 70 patients with CD developed CRC during 30 years of observation. The overall risk of CRC among patients with UC and CD was comparable with that of the general population. However, patients diagnosed with UC during childhood or as adolescents, patients with long duration of disease and those with concomitant primary sclerosing cholangitis were at increased risk. In this commentary, we discuss the mechanisms underlying carcinogenesis in IBD and current investigations of genetic susceptibility in IBD patients. Further advances will depend on the cooperative work by epidemiologist and molecular geneticists in order to identify genetic polymorphisms involved in IBD-associated CRC. The ultimate goal is to incorporate genotypes and clinical parameters into a predictive model that will refine the prediction of risk for CRC in colonic IBD. The challenge will be to translate these new findings into clinical practice and to determine appropriate preventive strategies in order to avoid CRC in IBD patients. The achieved knowledge may also be relevant for other inflammation-associated cancers.