Malignant tumors arising in inflammatory bowel disease

Colorectal cancer remains a major threat to patients with longstanding ulcerative colitis and Crohn colitis. Due to patients' and physicians' desires to avoid unnecessary surgery, prophylactic colectomies are rarely performed in these patients. Instead, caregivers and IBD patients tend to elect a program of dysplasia surveillance in an effort to simultaneously minimize cancer mortality and unnecessary colectomies. Although only circumstantial evidence supports the use of such a strategy as a means of reducing CRC-related mortality, dysplasia surveillance will remain the standard of care until better tests are available. Extra caution should be given to pediatric patients whose relative risk and lifetime risk of cancer is increased. Small intestinal cancer occurs at an increased rate in patients with Crohn enteritis, but the absolute risk remains small. Extraintestinal malignancies are uncommon in IBD but lymphomas, biliary tract cancers and squamous cell cancers of the skin may occur at an increased rate in IBD patients. The mechanisms for all of these processes remain elusive, but it is hoped that advances in molecular medicine will help to unravel these issues in the future.