Colorectal cancer risk in Crohn's disease.

There is recognized increased risk for colorectal cancer in patients with inflammatory bowel disease, particularly in long-standing and extensive ulcerative colitis. There also appears to be an increased rate of intestinal cancer in Crohn's disease, including both colon and small bowel sites. In Crohn's disease, evidence suggests that detection of colorectal cancer may be delayed with a worse prognosis. Some risk factors for cancer in Crohn's disease include the extent of inflammatory change within the colon and the presence of bypassed or excluded segments, including rectal "stump" cancer. In addition, the risk for other types of intestinal neoplasms may be increased in Crohn's disease, including lymphoma and carcinoid tumors. Earlier detection of colorectal cancer based on colonoscopy screening and surveillance may be achieved but, to date, this has not translated into a positive survival benefit. Moreover, newer staining methods and evolving micro-endoscopic techniques show promise, but have not significantly altered management. Future research should focus on development of molecular or other bio-markers that might predict future dysplasia or cancer development in Crohn's disease.