Current Status of Chromoendoscopy and Narrow Band Imaging in Colonoscopy

Abstract

Colonoscopy, the preferred procedure for colon cancer screening, has welldocumented limitations. To improve colonoscopy's effectiveness, augmented endoscopy techniques, such as chromoendoscopy and narrow band imaging (NBI) have been evaluated. Both techniques are inexpensive, safe, and relatively easy to perform. Chromoendoscopy has an increasingly important role in surveillance of IBD, but significant work is needed to determine the optimal staining techniques and mucosal surface pattern analysis before this technique can be incorporated into routine clinical practice. NBI is a much newer technology with far less data. Well-designed prospective randomized controlled trials have failed to identify a benefit of NBI in screening colonoscopy, in surveillance for high-risk populations or as an adjunct for therapeutic procedures. KEYWORDS: Chromoendoscopy, narrow band imaging, colonoscopy, endoscopyObjectives: On completion of this article, the reader should be able to discuss the techniques of chromoendoscopy and narrow band imaging in colonoscopy.In the United States, colorectal cancer is currently the fifth leading cancer, with an estimated 146,970 new cases annually. It is the second largest cause of cancer death: Approximately 49,920 died of the disease in 2009. 1 As dedicated colonoscopists, we must focus on our ability to meticulously detect and remove colorectal neoplasia with the ultimate goal being colorectal cancer prevention.The practice of removing neoplastic colonic lesions during colonoscopy to reduce the incidence of colorectal cancer has been justified by the results of the National Polyp Study Workgroup cohort study, which showed that colonoscopy with removal of identified polyps reduced the incidence of colorectal cancer 76 to 90%. 2 Currently, white light colonoscopy (colonoscopy), albeit imperfect, is the preferred colorectal cancer screening test. 3 It is the best screening test to both detect and remove colonic neoplasms. However, substantial miss rates for adenoma and cancers have been reported with colonoscopy. The colonoscopy-miss rate for adenomas is not completely understood, but has been well documented by several studies showing a significant discordance in adenoma detection rate (ADR) during screening colonoscopy among practicing colonoscopists. ADENOMA DETECTION RATEPublished ADRs during colonoscopy have ranged from 7% to 44%, whereas the mean number of adenomas detected per subject screen has ranged from 0.09 to 1.05. [4][5][6][7][8] To study more closely the missed adenoma rate of colonoscopy, same-day tandem (back-to-back) colonoscopies have shown an overall adenoma-miss

Advances in endoscopic imaging: Advantages and limitations

“…[9,10,12,13] NBI targeted biopsy can enhance dysplasia detection compared to WLE in the surveillance of inflammatory bowel disease. [14] Emerging data also supports the use of NBI in therapeutic procedures including ablation of Barrett's, endoscopic mucosal resection and ESD where the assessment of the margin is critical. However interpretation of contrast enhanced images require familiarity and may not be straight forward with considerable inter observer variation.…”

Colonoscopy: Advanced and Emerging Techniques—A Review of Colonoscopic Approaches to Colorectal Conditions

“…1A, 1B). 3 Debris is washed away and glucagon is administered to minimize gut contraction. The dye is typically sprayed on the mucosa via the working channel of the colonoscope.…”

“…18 Overall, chromoendoscopy may play a role in the surveillance of IBD, although uniformity of optimal staining techniques and analysis of mucosal surface patterns is required. 3…”

Endoscopy in the Diagnosis and Management of Complications of Inflammatory Bowel Disease

“…The technique is relatively simple, safe, and inexpensive. 101,102 Chromoendoscopy minimizes sampling errors in cancer surveillance of patients with IBD by enhancing dysplasia detection and delineating the borders between neoplastic and normal tissue. 103,104 A meta-analysis of prospective studies comparing surface chromoendoscopy with standard-definition white-light endoscopy (WLE) demonstrated a 7% (95% confidence interval, 3.3%-10.3%) incremental yield of chromoendoscopy with targeted biopsies over WLE with random biopsies for dysplasia detection and calculated a number needed to treat of 14.3 (95% confidence interval, 9.7-30.3) to detect 1 additional patient with dysplasia or cancer.…”