Surveillance and treatment for dysplasia in chronic inflammatory bowel diseases
Martin Götz, Tübingen
Gastroenterology 2015, 148:639-651
|SCENIC International Consensus Statement on Surveillance and Management of Dysplasia in Inflammatory Bowel Disease|
|Loren Laine, Tonya Kaltenbach, Alan Barkun, Kenneth R. McQuaid, Venkataraman Subramanian (6) and Roy Soetikno, for the SCENIC Guideline Development Panel|
Summary of Recommendations for Surveillance and Management of Dysplasia in Patients With Inflammatory Bowel Disease
Detection of dysplasia on surveillance colonoscopy
- When performing surveillance with white-light colonoscopy, high definition is recommended rather than standard definition (strong recommendation, low-quality evidence).
- When performing surveillance with standard-definition colonoscopy, chromoendoscopy is recommended rather than white-light colonoscopy (strong recommendation, moderate-quality evidence).
- When performing surveillance with high-definition colonoscopy, chromoendoscopy is suggested rather than white-light colonoscopy (conditional recommendation, low-quality evidence).
- When performing surveillance with standard-definition colonoscopy, narrow-band imaging is not suggested in place of white-light colonoscopy (conditional recommendation, low-quality evidence).
- When performing surveillance with high-definition colonoscopy, narrow-band imaging is not suggested in place of white-light colonoscopy (conditional recommendation, moderate-quality evidence).
- When performing surveillance with image-enhanced high-definition colonoscopy, narrow-band imaging is not suggested in place of chromoendoscopy (conditional recommendation, moderate-quality evidence).
Management of dysplasia discovered on surveillance colonoscopy
- After complete removal of endoscopically resectable polypoid dysplastic lesions, surveillance colonoscopy is recommended rather than colectomy (strong recommendation, very low-quality evidence).
- After complete removal of endoscopically resectable nonpolypoid dysplastic lesions, surveillance colonoscopy is suggested rather than colectomy (conditional recommendation, very low-quality evidence).
- For patients with endoscopically invisible dysplasia (confirmed by a GI pathologist) referral is suggested to an endoscopist with expertise in IBD surveillance using chromoendoscopy with high-definition colonoscopy (conditional recommendation, very low-quality evidence).
What you need to know
Patients with chronic inflammatory bowel disease (IBD) are at increased risk for the development of colorectal carcinomas and the corresponding precursor lesions. This applies both to patients with ulcerative colitis (UC) and also those with Crohn’s disease. The guideline recommendations presented here for surveillance of IBD patients — the Surveillance for Colorectal Endoscopic Neoplasia Detection and Management in Inflammatory Bowel Disease Patients: International Consensus (SCENIC) guidelines — were published simultaneously in the journals Gastroenterology and Gastrointestinal Endoscopy. They have also been endorsed by the American specialist associations, the American Society for Gastrointestinal Endoscopy and American Gastroenterological Association, as well as the Asian–Pacific Association of Gastroenterology, British Society of Gastroenterology, Canadian Association of Gastroenterology, European Society of Gastrointestinal Endoscopy, and Japan Gastroenterological Endoscopy Society. They are largely consistent with the European guidelines published by the European Crohn’s and Colitis Organization (ECCO) (1).
The incidence of intraepithelial neoplasia in IBD patients is in general probably slightly lower than was thought in the initial studies, but it is still increased in comparison with the unaffected population. The main problem is often shallow growth in the mucosa with (post-)inflammatory changes, which makes detection difficult. Patients with Crohn’s colitis that goes beyond ileocecal involvement also have a statistically increased risk and should receive surveillance in the same way as UC patients.
The recommendation to take untargeted step biopsies in addition to biopsies from all visible lesions is mainly based on studies that were carried out before the introduction of video endoscopy, and of high-definition (HD) video endoscopy in particular. In later studies, a large proportion of the lesions were already visible on standard endoscopy (2), and step biopsies were by contrast of little help (3).
High-resolution endoscopy is recommended for surveillance. It appears to be superior to standard endoscopy. This appears plausible, although the evidence for it is still weak (4).
If standard endoscopy without high resolution is being used, the procedure should be done with chromoendoscopy. Even in HD endoscopy, chromoendoscopy is superior to pure white-light endoscopy. Chromoendoscopy involves a white-light endoscopy procedure, supplemented with the spraying of dyes such as methylene blue or indigo carmine to increase the contrast between normal and pathological mucosa. This has been tested in eight studies in comparison with standard white-light endoscopy, and according to a meta-analysis, it leads to an approximate doubling of the number of patients in whom neoplasia can be found and also of the number of lesions detected. In another meta-analysis, the number of chromoendoscopies that have to be carried out in order to identify one additional patient with intraepithelial neoplasia was found to be 14.3 (5). Chromoendoscopy is therefore recommended both with standard endoscopy and also with HD endoscopy. Virtual chromoendoscopy procedures have not yet been able to replace dye-spraying (6, 7), but further research is continuing.
Virtual chromoendoscopy procedures (NBI, i-scan, and FICE) are not able to replace chromoendoscopy and are not recommended. The SCENIC group was unable to reach a consensus on the question of whether the new endoscopy procedures mean that step biopsies can be dispensed with. The ECCO guidelines take a clear position here in relation to routine surveillance (1). If surveillance is carried out with chromoendoscopy, there is no significant benefit from taking step biopsies as well. Step biopsies are thus recommended only with white-light endoscopy. This may compensate for the increased time requirements involved with chromoendoscopy.
A terminological change that would be of practical relevance has been proposed: the terms “visible lesion” (subdivided for practical purposes into “endoscopically resectable lesions” and “endoscopically unresectable lesions”) and “nonvisible lesion” should be replaced with “dysplasia-associated lesion or mass” (DALM), “adenoma-like lesion,” and “non–adenoma-like lesion.”
For endoscopic and macroscopic distinction between lesions, the SCENIC guideline takes the practical route also used in other guidelines and classifies lesions into those that are endoscopically visible and those that are not endoscopically visible and can only be detected with four-quadrant biopsies. Following extensive examinations, the former can be easily and curatively resected endoscopically if:
- Clear boundaries are visible (chromoendoscopy is helpful here).
- The lesion has been completely removed macroscopically.
- This is confirmed histologically.
- No other neoplasias in the immediate vicinity of the resection site are found on biopsies.
- The rest of the colon shows no further neoplasia.
Following complete endoscopic resection of a lesion, intensive surveillance is suggested instead of proctocolectomy. In a recently published meta-analysis including 376 patients with polypoid neoplasia who underwent resection, the annual incidence of the development of colorectal carcinoma was 0.5% (8). Whether this is acceptable to patients needs to be discussed with them on an individual basis (see also (9)).
In patients with nonvisible lesions (incidental biopsy findings), referral to an expert center is recommended. This is based on the fact that the appropriate approach for neoplasia (confirmed by reference histopathology) in an untargeted four-quadrant biopsy (nonvisible neoplasia) is more difficult to define. In such cases, an endoscopist with experience in surveillance of IBD patients should first attempt to use chromoendoscopy to locate the lesion (and resect it if appropriate). The high rates of simultaneous additional lesions and even carcinomas claimed in earlier studies are probably of little relevance in view of the better resolution provided by today’s instruments. Proctocolectomy may be discussed with the patient, but other studies also show that patients have reservations regarding such immediate “maximum therapy.” It was found that patients are only willing to agree to surgical colectomy when the risk of a simultaneous carcinoma is 73% on average (9). Tightly scheduled screening examinations (e.g., after 6 months) therefore seem appropriate.
In summary, HD chromoendoscopy is still the gold standard for screening colonoscopy in IBD patients. Intraepithelial neoplasias are no longer regarded as representing an immediate reason for proctocolectomy and can instead undergo good and curative resection with specific precautions. It is assumed that patients will comply with tightly scheduled follow-up screening procedures.
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