What Is the Risk? Epidemiology and Evidence for Surveillance Regimens

Patients with inflammatory bowel disease (IBD) have increased risk of colorectal cancer (CRC). The risk for CRC is positively correlated to the duration of disease, extent of colonic involvement, and severity of inflammation. After 8 to 10 years of IBD diagnosis, the risk for CRC rises substantially and screening colonoscopy is recommended. Surveillance colonoscopy interval ranges from 1 to 5 years depending on patient and disease-specific risk factors. IBD patients with high risk factors such as having concomitant primary sclerosing cholangitis, moderate-to-severe inflammation, first-degree relative with CRC at early age, or history of invisible dysplasia or high-risk visible dysplasia should undergo surveillance colonoscopy in 1 year. Meanwhile, those with minimal colonic involvement or ≥2 consecutive unremarkable examinations while in continuous remission may consider extending the surveillance interval to 5 years. Advance in colonoscopy technique such as chromoendoscopy using dyes and/or image digital processing (virtual chromoendoscopy) may enhance dysplasia detection and is the preferred method for IBD surveillance. In the era of high-definition colonoscope, the practice of obtaining extensive biopsies throughout the colon remains controversial but is generally recommended to improve the detection rate of invisible dysplasia. Endoscopic surveillance in IBD has been shown to result in earlier detection of CRC and improved prognosis.