It is known that patients with a long history of ulcerative colitis and Crohn’s disease with colonic involvement have an increased risk of developing colorectal cancer. Most cases are believed to arise from dysplasia, and surveillance colonoscopy has long been recommended to detect dysplasia.
In 2015 the American Gastroenterological Association and American Society for Gastrointestinal Endoscopy issued updated recommendations for the surveillance and management of dysplasia in patients with inflammatory bowel disease (IBD) — i.e., the Surveillance for Colorectal Endoscopic Neoplasia Detection and Management in Inflammatory Bowel Disease international Consensus (SCENIC) Recommendations.
The statement addressed the different types of endoscopic procedures and equipment to be used and recommended practices for removal of lesions or referral for colectomy. Significantly, the updated recommendations reflect a shift to the use of chromoendoscopy for patients with IBD during screening and surveillance.
Chromoendoscopy involves the use of dye sprayed onto the mucosa during the procedure with the aim of making dysplasia more visible.
Screening colonoscopy in IBD can be a complicated business because of the nature of IBC, said Fernando Velayos, MD, of the University of California San Francisco School of Medicine. “Part of what inflammation does is obscure the mucosa, so that some lesions can blend effortlessly with the inflammation. It can cause scarring that can also hide precancerous lesions, and you can develop inflammatory polyps that can mimic true polyps.
“Chromoendoscopy is not perfect, by any means,” he said. “But it is a way of addressing the problem of trying to find those lesions that are so hard to detect.”
Studies have shown that chromoendoscopy detects more precancerous lesions than regular colonoscopy does. As pointed out by Steven Naymagon, MD, and Thomas A. Ullman, MD, both of Mount Sinai School of Medicine in New York City, in an article in Gastroenterology & Hepatology, six prospective cross-sectional trials have favored chromoendoscopy in comparison with white light endoscopy (WLE), with an approximate two- to three-fold increase in dysplasia detection per patient.
And in a recent long-term prospective study led by James F. Marion, MD, also of Mount Sinai, the researchers followed 68 patients from June 2006 through October 2011. Each was analyzed by random biopsy, targeted WLE, and chromoendoscopy.
In the 208 examinations conducted, 44 dysplastic lesions in 24 patients were identified — six by random biopsy, 11 by WLE, and 27 by chromoendoscopy.
Ullman pointed out that while the “promise of chromoendoscopy is outstanding, and results have been very encouraging, there have been no studies showing a colorectal cancer mortality benefit, none with a morbidity benefit, no evidence to show a decreased colectomy rate, and no studies demonstrating cost savings or decreased patient burden.”
Two articles and an editorial in American Journal of Gastroenterology outline various aspects of the debate: An article by Erik Mooiweer, MD, PhD, and colleagues cast doubt on whether chromoendoscopy for surveillance in IBD actually increases the detection of dysplasia. The authors studied the outcomes of 440 colonoscopies in 401 patients with chromoendoscopy and compared them with 1,802 colonoscopies in 772 patients using WLE.
Dysplasia was detected during 48 surveillance procedures (11%) in the chromoendoscopy group as compared with 189 procedures (10%) in the WLE group (P=0.80). Targeted biopsies yielded 59 dysplastic lesions in the chromoendoscopy group, comparable to the 211 dysplastic lesions detected in the WLE group (P=0.30).
“Despite compelling evidence from randomized trials, implementation of chromoendoscopy for IBD surveillance did not increase the detection of dysplasia compared with use of WLE with targeted and random biopsies,” the authors concluded.
And in the same issue, Chang-Ho Ryan Choi et al reviewed 40 years of IBD surveillance at a London hospital and found that while the advent of chromoendoscopy has increased the rate of dysplasia detection, it did not lead to a reduction in overall colorectal cancer risk.
However, the authors also noted that their data showed a reduction in the incident rate of advanced and interval colorectal cancer, particularly over the last decade of the study, suggesting that chromoendoscopy “played an important role in reducing the risk of advanced and interval cancer.”
In an editorial accompanying the two articles, Peter D.R. Higgins, MD, PhD, of the University of Michigan, wrote that the field needs more prospective data on chromoendoscopy in IBD, and warned that embracing the procedure before the prospective data are in “could lead gastroenterologists down the path of prostate-specific antigen in urology.”
“There are important tradeoffs in cancer surveillance, and these have to be considered before embracing any new, more sensitive testing approach,” he said.
As for the ongoing debate surrounding chromoendoscopy, Velayos suggested that any new technology might at some point be controversial — i.e., “here’s a new procedure that does require a learning curve, and people want to know the value of the procedure. If it’s a procedure that detects more precancerous lesions, there is value in finding these, but there is also a question of whether these subtle lesions will become anything in the future. And if you have a much more sensitive exam, it should allow you to do colonoscopy much more frequently. But we are not at that point yet.”
And there are other questions that need to be answered as well, he continued. For example, who will perform the exam? “One of the things we need to define as a profession is whether this is something we want all endoscopists to do. It’s relatively simple, but it does add time, and a learning curve is required. So we have to decide whether this is something that should be done by specialty centers or is something everyone should do.
“And the fact is, if we want everyone to do it, we have to find to find ways to reimburse for the extra time. And that would be the most desirable, because it would allow patients to continue there under their regular gastroenterologists.”
“It’s a good procedure,” he concluded. “But there are important questions we need to answer as we try to define the value and what it improves upon.”