High Adherence to Surveillance Guidelines in Inflammatory Bowel Disease Patients Results in Low Colorectal Cancer and Dysplasia Rates, While Rates of Dysplasia are Low Before the Suggested Onset of Surveillance.

Background: Patients with Crohn's disease [CD] and ulcerative colitis [UC] are at increased risk for colorectal dysplasia [CRD] and colorectal cancer [CRC]. Adherence to CRC surveillance guidelines is reportedly low internationally.

Aim: To evaluate surveillance practices at the tertiary IBD Center of the McGill University Health Center [MUHC] and to determine CRD/CRC incidence.

Methods: A representative inflammatory bowel disease cohort with at least 8 years of disease duration [or with primary sclerosing cholangitis] who visited the MUHC between July 1 and December 31, 2016 were included. Adherence to surveillance guidelines was compared to modified 2010 British Society of Gastroenterology guidelines. Incidence rates of CRC, high-grade dysplasia [HGD], low-grade dysplasia [LGD] and colorectal adenomas [CRA] were calculated based on pathology.

Results: In total, 1356 CD and UC patients (disease duration: 12 [interquartile range: 6-22) and 10 [interquartile range: 5-19] years) were identified. The surveillance cohort consisted of 680 patients [296 UC and 384 CD]. Adherence to surveillance guidelines was 76/82% in UC/colonic CD. An adequate number of biopsies were taken in 54/54% of UC/colonic CD patients. The incidence of CRC/HGD in UC and CD with colonic involvement was 19.5/58.5 and 25.1/37.6 per 100,000 patient-years, respectively. The incidence of dysplasia before 8 years of disease duration was low in both UC/CD [19.5 and 12.5/100,000 patient-years] with no CRC detected. The CRA rate was 30/38% in UC/colonic CD.

Conclusion: High adherence to surveillance guidelines and low CRC and dysplasia, but not CRA rates were found, suggesting that adhering to updated, stratified, surveillance recommendations may result in low advanced neoplasia rates. The incidence of dysplasia before the start of surveillance was low.