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World J Gastroenterol. Aug 7, 2014; 20(29): 9872-9881
Published online Aug 7, 2014. doi: 10.3748/wjg.v20.i29.9872
Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis
Eun Ran Kim, Dong Kyung Chang
Eun Ran Kim, Dong Kyung Chang, Division of Gastroenterology, Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, South Korea
Author contributions: All the authors contributed equally to this manuscript.
Correspondence to: Dong Kyung Chang, MD, PhD, Division of Gastroenterology, Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Irwon-dong, Gangnam-gu, Seoul 135-710, South Korea.
Telephone: +82-2-34103409   Fax: +82-2-34106983
Received: November 13, 2013
Revised: March 4, 2014
Accepted: April 21, 2014
Published online: August 7, 2014

Patients with inflammatory bowel disease (IBD) are at increased risk for developing colorectal cancer (CRC), although the overall incidence of IBD-associated CRC has been diminishing in recent decades in western countries. As demonstrated in previous studies, the risk of CRC in IBD increases with longer duration, extent of colitis, a familial history of CRC, coexistent primary sclerosing cholangitis, and the degree of inflammation. The pathogenesis of CRC in IBD is poorly understood. Similar to sporadic CRC, IBD-associated CRC is a consequence of sequential episodes of genomic alteration. Multiple inter-related pathways, including immune response by mucosal inflammatory mediators, oxidative stress, and intestinal microbiota, are also involved the pathogenesis of IBD-associated CRC. Continuing colonic inflammation appears to be a factor in the development of CRC; therefore, anti-inflammatory agents such as 5-aminosalicylate compounds and immune modulators have been considered as potential chemopreventive agents. Colonoscopic surveillance is widely accepted as being effective in reducing the risk of IBD-associated CRC, although no clear evidence has confirmed that surveillance colonoscopy prolongs survival in patients with extensive colitis. The traditional recommendation has been quadrantic random biopsies throughout the entire colon; however, several guidelines now have endorsed chromoendoscopy with a target biopsy because of increasing diagnostic yields and reduced workloads for endoscopists and pathologists. New technologies such as narrow band imaging, confocal endomicroscopy, and autofluorescence imaging have not yet been confirmed as surveillance strategies in IBD.

Keywords: Inflammatory bowel disease, Colorectal cancer, Pathogenesis, Chemoprevention, Surveillance

Core tip: An updated comprehensive review on the risk, pathogenesis, prevention and diagnosis of colorectal cancer in inflammatory bowel disease.