Chromoendoscopy for detection of colonic mucosal neoplasms in ulcerative colitis

Abstract

See page 880 Chromoendoscopy has been used to improve the diagnostic yield in patients with gastrointestinal tumors. It is a procedure where enhancing dyes are sprayed onto the colonic mucosal surface using a spray catheter passed through a high-resolution or magnifying endoscope. Such an approach can dramatically improve detailed evaluation of the mucosal surface, allowing detection of very early preneoplastic lesions including aberrant crypt foci. This technique may also have value in screening patients with chronic ulcerative colitis who are at significantly higher risk of developing colorectal cancer. Moreover, endoscopic identification of colorectal neoplasms in this group is difficult because the lesions are characteristically flat. Unlike other substances such as indigo carmine, methylene blue is taken up by the intestinal epithelium resulting in a relatively stable staining pattern and the visualization of the openings of the glandular pits during chromoendoscopy (CE). In the study by Kiesslich et al., 263 patients with chronic ulcerative colitis were randomized to conventional colonoscopy or colonoscopy with CE. Five mucosal biopsy specimens were taken every 10 cm between rectum and cecum. Colonoscopy with CE was more accurate in providing correlation between the degree and extent of colonic inflammation and histopathological findings compared with conventional colonoscopy. In addition, this approach facilitated targeted biopsies and yielded more intraepithelial neoplastic lesions than colonoscopy alone (see Figure 1 as an example).Although the average time required for endoscopy was higher in the chromoendoscopy group than in the control group, these differences were not statistically significant. Furthermore, CE with methylene blue was associated with no side effects and is a safe and rapidly performed technique.