2015-07-13 19:32:36 UTC

Chromoendoscopy: Still Not Ready for Prime Time

July 19, 2015

Conventional white-light surveillance for IBD patients is still king.


Thomas A. Ullman, MD

Chief Medical Officer, Mount Sinai Doctors Faculty Practice, Senior Associate Dean for Clinical Affairs, Icahn School of Medicine at Mount Sinai, New York, NY

Read the other half of this AGA Perspectives point-counterpoint debate: Chromoendoscopy: This is What Progress Looks Like

The backbone of colorectal cancer prevention in inflammatory bowel disease (IBD), as in sporadic colorectal cancer prevention, has been colonoscopic screening and surveillance. The purpose of colonoscopic surveillance in IBD is to identify dysplasia and intervene to prevent its progression. Early in the history of dysplasia surveillance in IBD, intervention meant colectomy following the detection of dysplasia and continued periodic examinations for those who were dysplasia-free or those who felt that the risks of cancer following dysplasia were low enough to avoid the risks of colectomy. With the demonstration of the relative safety of continued surveillance following polypectomy1,2 and the understanding that most dysplasia in surveillance programs is visible,3,4 continued surveillance following polypectomy has become the norm, and a number of unneeded colectomies has been averted. The focus of surveillance shifted from taking multiple non-targeted biopsies to a strategy familiar to all endoscopists of polyp identification and removal. The goal, then, in improving surveillance through technologic advance has thus become improving polyp detection.

But while the focus on lesion identification has come to the fore, questions regarding the clinical utility of endoscopic advances must always remain the same, whether in IBD surveillance or in any endoscopic advance: what are the true benefits to the new technology?

There is no peer-reviewed evidence whatsoever that has demonstrated any benefit that accrues to IBD patients undergoing chromoendoscopic examinations compared to white light examinations.

The best of the newer methods of colonoscopic advances in IBD, at least in cross-sectional studies, has been the application of diluted methylene blue or indigo carmine to the colonic mucosal surface with careful inspection of the colon to better detect previously “invisible” flat dysplasia, techniques commonly referred to as chromoendoscopy. The promise of chromoendoscopy is outstanding and results have been very encouraging; greater detection of dysplasia on both a per-lesion and per-patient basis has been demonstrated in multiple studies from multiple centers.5–8 Every one of these studies, however, has been a cross-sectional process evaluation, in which the number of detected lesions using chromoendoscopy has been compared to the number of detected lesions using conventional white-light colonoscopy (or in one study the number of patients with detected lesions). No longitudinal studies have been reported in the peer-review literature. And so no comparisons to conventional white-light examinations have ever been performed for any clinically meaningful outcome. There are 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. In fact, there is no peer-reviewed evidence whatsoever that has demonstrated any benefit that accrues to patients undergoing chromoendoscopic examinations compared to white-light examinations. None.

Why not? Is it possible that chromoendoscopic IBD surveillance saves lives, decreases costs, and limits the time and burden on patients compared to conventional white-light examinations? Sure. But these are the missing studies. We should keep in mind that while benefits with improved dysplasia detection are possible, it’s also possible that the improved dysplasia detection demonstrated in the cross-sectional studies is limited to better viewing of small and clinically less important lesions that are not likely to be missed on the next surveillance examination prior to their becoming clinically important. The possibility and extent of such lead-time bias has never been investigated in IBD and not particularly well discussed in the chromoendoscopic literature. The benefit of chromoendoscopy, therefore, as of this writing is just theoretical as no benefits have been demonstrated.

Recently, the SCENIC group (in which I was a participant) published its consensus statements in multiple journals, including Gastroenterology.9,10 If fully adopted, the SCENIC recommendations will mandate that our fellow gastroenterologists be obliged to learn chromoendoscopic techniques and purchase high-definition scopes, high-definition processors and high-definition monitors to be in compliance. This was done in spite of the complete absence of longitudinal data supporting an outcome benefit or clinical utility to chromoendoscopy; as of this writing chromoendoscopy is a faith-based initiative. While there isn’t great evidence to support conventional white-light based surveillance practices either, I believe that gastroenterologists should continue to feel free to adopt or not to adopt chromoendoscopy as their go-to method of performing surveillance. One day, soon I hope, investigators will perform scientifically rigorous, longitudinal studies evaluating the benefits of chromoendoscopy, evaluating true patient-oriented outcomes like cancer morbidity or mortality, scope intervals or costs, all feasible if performed in a multi-centered fashion. Then we might come to understand the true value of chromoendoscopy. Until then, chromoendoscopy looks great and shows promise, but conventional white-light surveillance for IBD patients, as recommended in the AGA guidelines, is still king.11

Dr. Ullman receives research support from Genetech and also serves on the Crohn’s and Colitis Foundation of America government affairs committee.


1. Rubin, P.H., et al., Colonoscopic polypectomy in chronic colitis: conservative management after endoscopic resection of dysplastic polyps. Gastroenterology, 1999. 117(6): p. 1295-300.

2. Odze, R.D., et al., Long-term follow-up after polypectomy treatment for adenoma-like dysplastic lesions in ulcerative colitis. Clin Gastroenterol Hepatol, 2004. 2(7): p. 534-41.

3. Rutter, M.D., et al., Most dysplasia in ulcerative colitis is visible at colonoscopy. Gastrointest Endosc, 2004. 60(3): p. 334-9.

4. Rubin, D.T., et al., Are dysplasia and colorectal cancer endoscopically visible in patients with ulcerative colitis? Gastrointest Endosc, 2007. 65(7): p. 998-1004.

5. Kiesslich, R., et al., Methylene blueaided chromoendoscopy for the detection of intraepithelial neoplasia and colon cancer in ulcerative colitis. Gastroenterology, 2003. 124(4): p. 880-8.

6. Matsumoto, T., et al., Chromoscopy might improve diagnostic accuracy in cancer surveillance for ulcerative colitis. Am J Gastroenterol, 2003. 98(8): p. 1827-33.

7. Rutter, M.D., et al., Pancolonic indigo carmine dye spraying for the detection of dysplasia in ulcerative colitis. Gut, 2004. 53(2): p. 256-60.

8. Marion, J.F., et al., Chromoendoscopy-targeted biopsies are superior to standard colonoscopic surveillance for detecting dysplasia in inflammatory bowel disease patients: a prospective endoscopic trial. Am J Gastroenterol, 2008. 103(9): p. 2342-9

9. Laine L, Kaltenbach T, Barkun A, McQuaid KR, Subramanian V, Soetikno R; SCENIC Guideline Development Panel. SCENIC international consensus statement on surveillance and management of dysplasia in inflammatory bowel disease. Gastrointest Endosc. 2015 Mar;81(3):489-501.

10. Laine L, Kaltenbach T, Barkun A, McQuaid KR, Subramanian V, Soetikno R; SCENIC Guideline Development Panel. Gastroenterology. 2015 Mar;148(3):639-651. 11. Farraye, F.A., et al., AGA medical position statement on the diagnosis and management of colorectal neoplasia in inflammatory bowel disease. Gastroenterology, 2010. 138(2): p. 738-45.

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