4 WORLD GASTROENTEROLOGY NEWS FEBRUARY 2017 Editorial | Expert Point of View | Gastro 2016: EGHS-WGO | WDHD News | WGO & WGOF News | WGO Global Guidelines | Calendar of Events with the aim of accentuating surface abnormalities. The two most com-monly used dyes are methylene blue and indigo carmine. Methylene blue is an absorptive stain which colors normal tissue blue, while inflamed or dysplastic tissue has variable or absent absorption. Indigo carmine is a con-trast stain, which highlights mucosal topography and accentuates contours of dysplastic lesions. Most studies9,10,11 have demon-strated the superiority of CE over WLE in detection of dysplasia in IBD patients, although the retrospective study by Mooiweer and colleagues found that WLE-targeted biopsies had a higher yield of neoplasia compared to CE12. The American Society of Gastrointestinal Endoscopy and several international society guide-lines advocate for CE with targeted biopsies as the preferred surveillance strategy 9, 11, 13 . Although there is a strong recommendation for CE when using standard-definition scopes, there is only a conditional recom-mendation for its application when using high-definition scopes9. No specific recommendations have been made regarding random biopsies in patients who undergo high-definition colonoscopy or WLE plus CE. These methods presumably obviate the need for random biopsies. Logistics of CE must be taken into consideration, such as cost, training requirements, quality metrics, CPT coding and staff training. Compared to random biopsies, CE has the potential for cost-savings14 by collect-ing fewer specimens. Additionally, patients without evidence of dysplasia during this very sensitive exam can theoretically lengthen the interval between their colonoscopies, thus de-creasing the total number of lifetime colonoscopies and associated costs per person, and overall. Conversely, CE increases the length of each procedure on average, 15 and may alternatively create additional costs due to the increased number of colonoscopies and colectomies in patients in whom dysplasia is detected. The long-term benefits of these surveillance strategies are important considerations when comparing dif-ferent modalities. Although most studies have shown that CE may unmask more dysplasia in patients, data regarding the long-term benefits of chromoendoscopy over WLE is sparse. The outcome of dysplasia detected by CE is unknown, which yields uncertainty in the management of these patients. In the longitudinal study by Marion et al., no cancer was found among colon specimens resected for dysplasia that had been identified during CE exams10. A nega-tive CE exam has been suggested to be the best predictor of a dysplasia-free outcome10 , although larger, longitu-dinal studies are needed to confirm this benefit. Regardless of the surveillance method, guidelines suggest that complete endoscopic resection of dysplasia, if possible, with biopsies of the surrounding mucosa to exclude the presence of dysplasia be per-formed11. Surveillance colonoscopy after complete resection of dysplasia is recommended, rather than colectomy. Unresectable lesions, high-grade dys-plasia found only on random biopsy, or multifocal low-grade dysplasia still may be indications for proctocolec-tomy. Patients with confirmed invis-ible dysplasia should be referred to an endoscopist with expertise in IBD surveillance. Patients and physicians should be aware of the limitations of dysplasia surveillance in IBD patients. While the presence of inflammation, limited bowel preparation, bowel strictures and pseudopolyposis may limit the effectiveness of these techniques for every gastroenterologist, the skill level of each gastroenterologist in detecting and adequately removing identified lesions varies widely. Other universal limitations include the reality that some endoscopists may not follow the guidelines in practice, and certainly some patients may not follow recommendations after detec-tion of dysplasia. This permits several potential gaps in follow-up and allows for variable adherence by both patient and endoscopist. Dysplasia surveillance has advanced significantly with the advent of high-definition WLE and CE, but more studies are needed to address the necessity of CE during high-definition exams. While CE offers enhanced visualization of mucosa and a higher yield for dysplasia detection, addi-tional studies are needed to evaluate the practicality of this modality in busy clinical settings, the natural his-tory of dysplasia found only with CE, and the potential for increased burden of protocolectomies in patients with dysplasia. One should always remem-ber that while the immediate aim of surveillance is to detect dysplasia, the most important goal is to prevent colorectal cancer morbidity and mortality while avoiding unnecessary colectomy. References 1 Bernstein CN, Shanahan F, Wein-stein WM. Are we telling patients the truth about surveillance colonoscopy in ulcerative colitis? Lancet. 1994; 343(8889):71-4. 2 Lutgens MW1, van Oijen MG, van der Heijden GJ, et al. De-clining risk of colorectal cancer in inflammatory bowel disease: an updated meta-analysis of population-based cohort studies. Inflamm Bowel Dis. 2013;19:789- 799. 3 Eaden JA, Abrams KR, Mayberry JF. The risk of colorectal cancer in ulcerative colitis: a meta analysis. Gut.2001;48:526–535. 4 Eaden JA, Mayberry JF. Guide-lines for screening and surveillance of asymptomatic colorectal cancer Continued from first page.
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