the risk of developing colon cancer is 20 times higher for patients with inflammatory bowel disease than it is for the general population. the association with colon cancer is more clearly established in ulcerative colitis than in crohn's disease. an increased risk most likely also exists however for patients with crohn's disease that affects the colon. in ulcerative colitis the risk of acquiring colon cancer increases according to how much of the colon is involved and the duration of colitis. thus after about eight to 10 years of ulcerative colitis especially if the entire colon is involved the risk of developing colon cancer substantially increases. other risk factors for colon cancer in ibd patients include a liver disease called primary sclerosing cholangitis a family history of colon cancer and a history of liver transplantation. additional possible risk factors include the use of concurrent immunosuppressive medications and a deficiency of the vitamin folic acid.
does colon cancer occur in inflammatory bowel disease?