Cancer in inflammatory bowel disease.

The first case of cancer in inflammatory bowel disease (IBD) was reported at The Mount Sinai Hospital in 1925 in a patient with ulcerative colitis (UC). In 1956, carcinoma of the jejunum was described in a patient with regional enteritis (Crohn's disease [CD]). IBD cancers are preceded by dysplasia, and the relative risk increases with duration of the IBD. CD cancers are more proximally distributed than are UC cancers. Both tend to occur at the site of the overt disease and both develop at earlier ages (47 UC, 50 CD) than in the de novo colorectal cancer (70 years). The absolute cumulative colon cancer frequencies (8% UC, 7% CD) are identical after 20 years, emphasizing the importance of regular surveillance in both types of IBD. Moreover, the increased risk of colon cancer exists in patients with CD even when CD is confined to the small bowel, and patients with IBD have increased risks of developing extraintestinal and reticuloendothelial tumors in both CD and UC, as well as ano-vulval and malignant melanoma in CD. Colitic colorectal cancers are often diffuse, extensive, multiple and right-sided with insidious presentation. The prognosis is no worse after operation than that of de novo colon cancer. Most small bowel cancers in CD are adenocarcinomas, rather than sarcomas, and present at a younger age, more diffusely and more distally than de novo cancers, usually making them undiagnosable at a curable early stage; indeed, two-thirds present with intestinal obstruction. Strictures of the colon are common in patients with IBD, and they have a 10-fold risk for colon cancer, 30-fold for UC, and 6-fold for CD. The risk increases with disease duration. The indications for surgery are absolute, relative and incidental, and the procedures include segmental resection, total proctocolectomy, subtotal colectomy and palliative procedures.