Colorectal cancer in inflammatory bowel disease

Abstract

Patients with long-standing inflammatory bowel disease have an increased risk of developing colorectal cancer (CRC). CRC risk increases with longer duration of colitis, greater anatomic extent of colitis, the presence of primary sclerosing cholangitis, family history of CRC and severity of inflammation of the colon. Chemoprevention includes aminosalicylates, ursodeoxycholic acid, and possibly folic acid. To reduce CRC mortality in IBD, colonoscopic surveillance remains the major way to detect early mucosal dysplasia. When dysplasia is confirmed, proctocolectomy is considered for these patients. Ulcerative colitis patients with total proctocolectomy and ileal pouch anal-anastomosis have a rather low risk of dysplasia in the ileal pouch, but the anal transition zone should be monitored periodically. New endoscopic and molecular screening approaches may further refine our current surveillance guidelines and our understanding of the natural history of dysplasia.

Keywords: Colorectal neoplasms; Dysplasia; Inflammatory bowel disease.

Fig. 1

Comparison of molecular alterations in sporadic colon cancer and colitis-associated colon cancer. MSI, microsatellite instability; DCC/DPC4, deleted in colon cancer/deletedin pancreatic cancer-4; APC, adenomatous polyposis coli; k-ras, Kirsten-ras. Modified from Ref. 61, with permission.

Fig. 2

Invasive low-grade tubuloglandular adenocarcinoma in a patient with ulcerative colitis. (A) The cancer arises directly from mucosa that exhibits low-grade dysplasia on the surface. Biopsies of the surface would be interpreted as flat LGD. (B) High power view of inset in left panel. The invasive, malignant glands are well differentiated and manifest rather low-grade cytological features. There is little or no desmoplastic reaction around the glands. Courtesy of Noam Harpaz, MD, PhD. (and Ref. 43, with permission).

Fig. 3

Suggested management scheme for dysplasia in IBD. Modified from Ref. 61, with permission.

Fig. 4

A slightly raised, but poorly visible flat dysplastic lesion with LGD in a patient with longstanding UC (A). After dye spray with methylene blue, the lesion and its margin are much better defined (B). Courtesy of Jerome D. Waye, M.D.