Colonoscopic Surveillance in Inflammatory Bowel Disease

Thomas A Ullman


Curr Opin Gastroenterol. 2005;21(5):585-588. 

In This Article

The Coming of Chromoendoscopy and Other Endoscopic Techniques

A key problem in all the literature of dysplasia surveillance in ulcerative colitis centers on the idea that the worst finding at colonoscopy is at best an estimate of the worst finding actually present in the colon. This has been termed sampling error. With so great a surface area available and with the limited diameter of biopsy forceps, it has been demonstrated that a large number of random biopsies are necessary to exclude the presence of dysplasia. Rubin et al.[8] of Seattle deserve the credit for demonstrating to all of us that 56 properly oriented jumbo biopsy forceps are needed to rule out dysplasia with just 95% certainty. The endoscopist's time and money for histopathologic review are therefore substantial impediments to accurate and cost-effective surveillance.

In an effort to reduce sampling error and decrease biopsy number, several strategies have been touted. Of late, three publications on chromoendocsopy have demonstrated a greater yield for dye-spray targeted biopsies compared with numerous nontargeted biopsies. In a randomized trial by Kiesslich et al.,[20] intraepithelial neoplasia was more than three times as likely to be detected using chromoendoscopy compared with surveillance using nontargeted biopsies (32/84 compared with 10/81; P = 0.003). Using indigo carmine in back-to-back colonoscopies with each patient serving as his or her own control, Rutter et al.[21] detected no dysplasia in 2904 nontargeted biopsies in 100 patients, but in targeted biopsying, nine dysplastic lesions were detected, seven of which were visible only with dye spraying.

In addition to the use of dye sprays, coapplication of magnifying endoscopy for improved detection and pit pattern description and the additional use of confocal microscopy have been proposed to assist in the accuracy of dysplasia diagnosis.

Other techniques that have been proposed (but not yet carefully studied) include laser fluorescence spectroscopy for in-situ dysplasia diagnosis and fecal DNA testing. Whether these or other tests will complement or replace conventional white light colonoscopy remains to be seen.


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