Does Chromoendoscopy with Structure Enhancement Improve the Colonoscopic Adenoma Detection Rate?

Background and Study Aims: Colonoscopy is still considered the standard investigation for the detection of colorectal adenomas, but the miss rate, especially for small and flat lesions, remains unacceptably high. Chromoscopy has been shown to increase the yield for lesion detection in inflammatory bowel disease. The aim of this randomized prospective study was to determine whether a combination of chromoscopy and structure enhancement could increase the adenoma detection rate in high-risk patients.
Patients and Methods: All patients included in the trial had a personal history of colorectal adenomas and/or a family history of colorectal cancer (but excluding genetic syndromes). They were randomized to one of two tandem colonoscopy groups, with the first pass consisting of conventional colonoscopy for both groups, followed by either chromoscopy and structure enhancement (the “study” group) or a second conventional colonoscopy (the control group) for the second-pass colonoscopy. All detected lesions was examined histopathologically after endoscopic resection or biopsy. The principal outcome parameter was the adenoma detection rate; the number, histopathology, and location of lesions was also recorded.
Results: A total of 292 patients were included in the study (146 patients in each group). The patients’ demographic characteristics, the indications for colonoscopy, and the quality of bowel preparation were similar in the two groups. There was a significant difference between the two groups with respect to the median duration of the examination (18.9 minutes in the control group vs. 27.1 minutes for the study group, P < 0.001). Although more hyperplastic lesions were detected throughout the colon in the study group (P = 0.033), there was no difference between the two groups in either the proportion of patients with at least one adenoma or in the total number of adenomas detected. Chromoscopy and structure enhancement diagnosed significantly more diminutive adenomas (< 5mm) in the right colon, compared with controls (P = 0.039).
Conclusions: On the basis of our results we cannot generally recommend the systematic use of chromoscopy and structure enhancement in a high-risk patient population, although the detection of small adenomas in the proximal colon was improved.

References

• 1 Muto T, Bussey H, Morson B C. The evolution of cancer of the colon and rectum.  Cancer. 1975;  36 2251-2270
• 2 Winawer S J, Zauber A G, O’Brien M J. et al . Randomized comparison of surveillance intervals after colonoscopic removal of newly diagnosed adenomatous polyps.  N Engl J Med. 1993;  328 902-906
• 3 Hixson L S, Fennerty M B, Sampliner R E. et al . Prospective study of the frequency and size distribution of polyps missed by colonoscopy.  J Natl Cancer Inst. 1990;  82 1769-1772
• 4 Rex D K, Cutler C S, Lemmel G T. et al . Colonoscopy miss rates of adenomas determined by back-to-back colonoscopies.  Gastroenterology. 1997;  112 24-28
• 5 Kim C Y, Fleischer D E. Colonic chromoscopy: a new perspective on polyps and flat adenomas.  Gastrointest Endosc Clin N Am. 1997;  7 423-437
• 6 Kiesslich R, Fritsch J, Holtmann M. et al . Methylene blue-aided chromoendoscopy for the detection of intraepithelial neoplasia and colon cancer in ulcerative colitis.  Gastroenterology. 2003;  124 880-888
• 7 Hurlstone D P, Sanders D S, Lobo A J. et al . Indigo carmine-assisted high-magnification chromoscopic colonoscopy for the detection and characterisation of intraepithelial neoplasia in ulcerative colitis: a prospective evaluation.  Endoscopy. 2005;  37 1186-1192
• 8 Rutter M D, Saunders B P, Schofield G. et al . Pancolonic indigo carmine dye spraying for the detection of dysplasia in ulcerative colitis.  Gut. 2004;  53 256-260
• 9 Brooker J, Saunders B, Shah S. et al . Total colonic dye-spray increases the detection of diminutive adenomas during routine colonoscopy: a randomized controlled trial.  Gastrointest Endosc. 2002;  56 333-338
• 10 Winawer S J, Zauber A G, Ho M N. et al . Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup.  N Engl J Med. 1993;  329 1977-1981
• 11 Kiesslich R, Von Bergh M, Hahn M. et al . Chromoendoscopy with indigo carmine improves the detection of adenomatous and nonadenomatous lesions in the colon.  Endoscopy. 2001;  33 1001-1006
• 12 Lee J H, Kim J W, Cho Y K. et al . Detection of colorectal adenomas by routine chromoendoscopy with indigocarmine.  Am J Gastroenterol. 2003;  98 1284-1288
• 13 Rembacken B J, Fujii T, Cairns A. et al . Flat and depressed colonic neoplasms: a prospective study of 1000 colonoscopies in the UK.  Lancet. 2000;  355 1211-1214
• 14 Jaramillo E, Watanabe M, Slezak P, Rubio C. Flat neoplastic lesions of the colon and rectum by high-resolution video endoscopy and chromoscopy.  Gastrointest Endosc. 1995;  42 114-122
• 15 Hurlstone D P, Cross S S, Slater R. et al . Detecting diminutive colorectal lesions at colonoscopy: a randomised controlled trial of pan-colonic versus targeted chromoscopy.  Gut. 2004;  53 376-380
• 16 Painter J E, O’Dwyer S T, Watson A J. et al . The routine use of chromoscopy is of no benefit in flexible sigmoidoscopy screening for colorectal cancer.  Gut. 1999;  44 A99