PHILADELPHIA - The risk of both colorectal cancer and CRC-related mortality can be reduced in patients with inflammatory bowel disease by adhering to guideline-directed colonoscopy surveillance recommendations, according to a large retrospective cohort study presented at the annual meeting of the American College of Gastroenterology.
After adjustment for age, sex, duration of disease, type of IBD, and coexisting primary cholangitis, the odds ratio (OR) for CRC was reduced by 35% (OR, 0.65; 95% confidence interval, 0.45-0.93), according to Dr. Ashwin Ananthakrishnan, a gastroenterologist at Massachusetts General Hospital, Boston.
Dr. Ashwin Ananthakrishnan
Many professional societies, including the ACG, recommend colonoscopy surveillance in IBD patients within 8-10 years of diagnosis, and subsequently at 2- to 3-year intervals, but these recommendations were created without direct evidence of benefit. The aim of the study was to evaluate the effect of colonoscopy surveillance on CRC incidence.
The 6,823 patients who formed the cohort were gathered through electronic medical records from multiple participating institutions. The incidence of CRC was compared in the 2,764 patients who underwent colonoscopy within 3 years prior to a diagnosis of CRC or the end of the follow-up period and the 4,059 without colonoscopy in this period.
Of the 154 cases of CRC observed during follow-up, 43 occurred in the group that had undergone colonoscopy and 111 occurred in the group that had not, producing an incidence of 1.6% and 2.7%, respectively. Although there were potentially relevant differences between the two patient groups – the colonoscopy group had a lower incidence of ulcerative colitis (49% vs. 54%) and a younger age (47 vs. 49 years) – the advantage persisted after adjustment.
In addition, death due to CRC was lower in the group that underwent colonoscopy in the past 3 years (14% vs. 34%; P = .012), producing an odds ratio of 0.34 (95% CI, 0.12-0.95) for this endpoint.
Dr. Ananthakrishnan acknowledged that the limitations of the study included recruitment from a largely tertiary-center population and lack of information on the extent of IBD or the stage of cancer, but he called the overall findings “robust.” He concluded that these data may provide the best support yet for the current guidelines.
“I do not think this suggests we should be doing anything any differently,” Dr. Ananthakrishnan said in an interview, “but it does reinforce the value of the guidelines for those who may not be applying them now.”
Asked for his perspective on these data, Dr. Stephen Hanauer, professor of gastroenterology and hepatology, Northwestern University, Chicago, was more circumspect.
“There is evidence that the incidence of CRC is going down in patients with IBD, and it may be due to better surveillance, but this study has some limitations,” Dr. Hanauer commented. “It could have been just that those who received colonoscopy had less advanced IBD and a lower cancer risk.”
The definitive answer is dependent on a prospective and randomized trial, but there is limited demand for such a study when the increased risk of CRC in patients with IBD is well accepted, making surveillance attractive. Dr. Hanauer did not dispute the logic behind current screening recommendations.
Dr. Ananthakrishnan reported having no relevant financial relationships to disclose.