Clin Endosc > Volume 46(2); 2013 > Article
Kim: Introduction: What Are New Roles of Current Colonoscopy?

Abstract

The recent advances in endoscopic imaging technologies make great changes in the management of colorectal polyps. These changes include optical histologic diagnosis with high definition colonscopy, new management strategies such as resect and discard or do not resect, and differentiation of depth of submucosal invasion. In this focused review series, these new paradigms in management of colorectal polyps are discussed by three, world famous authors. First, Amit Rastogi explained optical diagnosis of small colorectal polyp with high definition colonoscopy using narrow band imaging. Second, Cesare Hassan explained new paradigms for colonoscopic management of diminutive colorectal polyps: resect and discard or do not resect. In the last, Shinji Tanaka described, in detail, endoscopic assessment of invasive colorectal cancer: slight vs. deep submucosal invasion. These focused review series introduce the new roles of current colonoscopy to readers and will help the readers to know how to use the new imaging technologies and paradigms in clinical practices.

INTRODUCTION

Colorectal cancer (CRC) is a leading cause of cancer death worldwide. Colonoscopy has been effective in detection and removal of colorectal adenoma and colonoscopic polypectomy has prevented a good part of CRCs.1,2 Because most CRCs arise from preexisting adenomatous polyps, all identified colorectal adenomas during colonoscopy are to be removed.
Recently, the demand for colonoscopy is increasing rapidly, together with the increasing interest on health promotion and CRC. In company with increased numbers of colonoscopy, employing high-definition colonoscopy facilitated the detection of colorectal polyps and, recently, colorectal polyps have become an extremely common disease. Most polyps detected with current colonoscopy are small or, mostly, diminutive.3,4

THE PROBLEMS OF CURRENT MANAGEMENT OF COLORECTAL POLYPS

Currently, diminutive colorectal polyps are resected endoscopically and submitted for pathologic assessment for precise diagnosis. The important background of current management is that it is difficult to differentiate between adenomatous and hyperplastic polyps by only standard white light colonoscopy. This handicap necessitates the indiscriminate removal of all polyps detected during colonoscopy, thus increasing the costs and risks associated with potentially avoidable polypectomies. However, most of these polyps are hyperplastic or adenomatous polyps without advanced features5-7 and optical histologic diagnosis of these polyps has become available by great improvement of imaging techniques. So, current practice results in unnecessary costs, waste of medical resources and risks associated with unnecessary polypectomy. New clinical approaches for the management of colorectal polyps have appeared due to these backgrounds.

THE NEW ROLES OF CURRENT COLONOSCOPY

Current colonoscopy produces a high definition image and narrow band image (NBI; Olympus, Tokyo, Japan) allows enhancing the visualization of superficial mucosal and vascular pattern by only simple manipulation. The improved quality of endoscopic image can be helpful in predicting their histology; several studies have shown good predictive accuracy of high definition colonoscopy and NBI without magnification for polyp histology.8-11
The encouraging results about optical histologic diagnosis of diminutive colorectal polyps using new imaging technologies could change the current management of such polyps.12 Recently, two new paradigms have been introduced by the American Society for Gastrointestinal Endoscopy. First, "resect and discard" strategy is an optical assessment of histology followed by resection and discarding of the diminutive polyp without pathologic assessment. Second, "do not resect" is to leave diminutive hyperplastic polyps in the distal colon in place without resection. These paradigms could resolve the problems of current management of colorectal polyps.
In addition, high definition colonoscopy with NBI can observe the microvessels and pit-like pattern of superficial mucosa of polyp and differentiate between adenoma and carcinoma based on these patterns. By using NBI magnifying observation to analyze microvessel visibility, vascular diameter and distribution heterogeneity, and the presence and irregularity of pit-like pattern, it becomes possible to discriminate submucosal carcinoma as slight versus deep invasion.13-15

THE CONTENTS OF THIS FOCUSED REVIEW SERIES

The purpose of this review series is to help the readers to understand the new roles of current colonoscopy, especially new imaging technologies and new paradigms. First, Rastogi et al.9 kindly explained unique images among histologic differences with high definition colonoscopy using narrow band imaging. Second, Cesare Hassan kindly explained the background and validity of the new paradigms for colonoscopic management of diminutive colorectal polyps. In the last, Shinji Tanaka described, in detail, the unique patterns in high definition and maginifying colonoscopy as well as morphologic characteristics of submucosal cancer.

Acknowledgments

I would like to thank heartily all invited authors for accepting our invitation gladly and providing wonderful manuscripts with untiring efforts despite their busy schedule. Also, I would like to thank senior deputy editor, Prof. Ki Baik Hahm for giving me the chance to organize this focused review series. I hope that these reviews would be of any help and provide valuable references to the readers of Clinical Endoscopy.

NOTES

The author has no financial conflicts of interest.

References

1. Winawer SJ, Zauber AG, Ho MN, et al. The National Polyp Study Workgroup. Prevention of colorectal cancer by colonoscopic polypectomy. N Engl J Med 1993;329:1977–1981. 8247072.
crossref pmid
2. Citarda F, Tomaselli G, Capocaccia R, Barcherini S, Crespi M. Italian Multicentre Study Group. Efficacy in standard clinical practice of colonoscopic polypectomy in reducing colorectal cancer incidence. Gut 2001;48:812–815. 11358901.
crossref pmid pmc
3. Chen SC, Rex DK. Endoscopist can be more powerful than age and male gender in predicting adenoma detection at colonoscopy. Am J Gastroenterol 2007;102:856–861. 17222317.
crossref pmid
4. Rex DK, Helbig CC. High yields of small and flat adenomas with high-definition colonoscopes using either white light or narrow band imaging. Gastroenterology 2007;133:42–47. 17631129.
crossref pmid
5. Church JM. Clinical significance of small colorectal polyps. Dis Colon Rectum 2004;47:481–485. 14994108.
crossref pmid
6. Butterly LF, Chase MP, Pohl H, Fiarman GS. Prevalence of clinically important histology in small adenomas. Clin Gastroenterol Hepatol 2006;4:343–348. 16527698.
crossref pmid
7. Rex DK, Overhiser AJ, Chen SC, Cummings OW, Ulbright TM. Estimation of impact of American College of Radiology recommendations on CT colonography reporting for resection of high-risk adenoma findings. Am J Gastroenterol 2009;104:149–153. 19098863.
crossref pmid
8. Rex DK. Narrow-band imaging without optical magnification for histologic analysis of colorectal polyps. Gastroenterology 2009;136:1174–1181. 19187781.
crossref pmid
9. Rastogi A, Keighley J, Singh V, et al. High accuracy of narrow band imaging without magnification for the real-time characterization of polyp histology and its comparison with high-definition white light colonoscopy: a prospective study. Am J Gastroenterol 2009;104:2422–2430. 19584829.
crossref pmid
10. Sikka S, Ringold DA, Jonnalagadda S, Banerjee B. Comparison of white light and narrow band high definition images in predicting colon polyp histology, using standard colonoscopes without optical magnification. Endoscopy 2008;40:818–822. 18668472.
crossref pmid
11. Rogart JN, Jain D, Siddiqui UD, et al. Narrow-band imaging without high magnification to differentiate polyps during real-time colonoscopy: improvement with experience. Gastrointest Endosc 2008;68:1136–1145. 18691708.
crossref pmid
12. Rex DK, Fennerty MB, Sharma P, Kaltenbach T, Soetikno R. Bringing new endoscopic imaging technology into everyday practice: what is the role of professional GI societies? Polyp imaging as a template for moving endoscopic innovation forward to answer key clinical questions. Gastrointest Endosc 2010;71:142–146. 19922926.
crossref pmid
13. Wada Y, Kudo SE, Kashida H, et al. Diagnosis of colorectal lesions with the magnifying narrow-band imaging system. Gastrointest Endosc 2009;70:522–531. 19576581.
crossref pmid
14. Kanao H, Tanaka S, Oka S, Hirata M, Yoshida S, Chayama K. Narrow-band imaging magnification predicts the histology and invasion depth of colorectal tumors. Gastrointest Endosc 2009;69(3 Pt 2):631–636. 19251003.
crossref pmid
15. Yoo HY, Lee MS, Ko BM, et al. Correlation of narrow band imaging with magnifying colonoscopy and histology in colorectal tumors. Clin Endosc 2011;44:44–50. 22741112.
crossref pmid pmc
TOOLS
PDF Links  PDF Links
PubReader  PubReader
ePub Link  ePub Link
XML Download  XML Download
Full text via DOI  Full text via DOI
Download Citation  Download Citation
  Print
Share:      
METRICS
1
Crossref
1
Scopus
4,301
View
30
Download
Related article
How to Pursue the Clearing Colonoscopy?  2010 March;42(48)
Editorial Office
Korean Society of Gastrointestinal Endoscopy
#817, 156 Yanghwa-ro (LG Palace, Donggyo-dong), Mapo-gu, Seoul, 04050, Korea
TEL: +82-2-335-1552   FAX: +82-2-335-2690    E-mail: CE@gie.or.kr
Copyright © Korean Society of Gastrointestinal Endoscopy.                 Developed in M2PI
Close layer