Endoscopy 2013; 45(05): 350-356
DOI: 10.1055/s-0032-1326348
Original article
© Georg Thieme Verlag KG Stuttgart · New York

Prevalence of flat lesions in a large screening population and their role in colonoscopy quality improvement

K. Reinhart
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
2   Department of Internal Medicine III, Division of Gastroenterology and Hepatology. Medical University Vienna, Austria
,
C. Bannert
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
2   Department of Internal Medicine III, Division of Gastroenterology and Hepatology. Medical University Vienna, Austria
,
D. Dunkler
3   Center for Medical Statistics, Informatics and Intelligent Systems, Section for Clinical Biometrics, Medical University Vienna, Austria
,
P. Salzl
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
2   Department of Internal Medicine III, Division of Gastroenterology and Hepatology. Medical University Vienna, Austria
,
M. Trauner
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
2   Department of Internal Medicine III, Division of Gastroenterology and Hepatology. Medical University Vienna, Austria
,
F. Renner
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
4   Department of Internal Medicine, Krankenhaus der Barmherzigen Schwestern Ried/Innkreis, Austria
,
P. Knoflach
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
5   Department of Internal Medicine I, Klinikum Wels, Wels, Austria
,
A. Ferlitsch
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
2   Department of Internal Medicine III, Division of Gastroenterology and Hepatology. Medical University Vienna, Austria
,
W. Weiss
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
,
M. Ferlitsch*
1   Austrian Society for Gastroenterology and Hepatology: Quality Assurance Working Group
2   Department of Internal Medicine III, Division of Gastroenterology and Hepatology. Medical University Vienna, Austria
› Author Affiliations
Further Information

Publication History

submitted 09 November 2011

accepted after revision 04 December 2012

Publication Date:
24 April 2013 (online)

Background and study aims: Flat lesions pose new challenges for endoscopists, but the importance of detecting them is still controversial. Most screening studies do not survey macroscopic polyp morphology. The aims were to evaluate the percentage of flat polyp findings in a large asymptomatic adult screening population (n = 52 521), to assess the impact of shape and size on malignant transformation, and to assess the role of flat lesions regarding quality assurance in colorectal cancer prevention.

Material and methods: Retrospective analysis of screening colonoscopies performed between 2007 and 2011 according to the Austrian “Quality management for colon cancer prevention” program.

Results: 17 771 patients with polyps were included in the study. Patients with flat polyps represented 24.2 % (n = 4293), 62.4 % (n = 11 097) were classified as having sessile and 13.4 % (n = 2381) as pedunculated polyps. Among those with flat polyps 51.4 % had adenomas (n = 2207). High grade dysplasia (HGD) was found in 2.1 % (n = 47) of flat adenomas, in 1.5 % (n = 89) of sessile adenomas and 4.7 % (n = 92) of pedunculated adenomas (P < 0.0001. The risk for containing HGD was 1.0 % for flat lesions ≤ 10 mm in size compared with 10.3 % for lesions > 10 mm, and 1.0 % for polypoid lesions ≤ 10 mm compared with 9.3 % for lesions > 10 mm (P < 0.0001). Multivariable logistic regression showed that polyp size (P < 0.0001) but not polyp shape (P = 0.438) is an independent predictor for HGD. Adenoma detection rate (ADR) correlated weakly with the flat polyp detection rate (Pearson r = 0.24).

Conclusion: Malignant potential of polyps is mostly affected by size but not by shape. Since flat polyp detection rate only correlates poorly with ADR we do not recommend its incorporation in quality assured screening colonoscopy.

* on behalf of the Quality Assurance Working Group


 
  • References

  • 1 Muto T, Bussey HJ, Morson BC. The evolution of cancer of the colon and rectum. Cancer 1975; 36: 2251-2270
  • 2 Ekelund G, Lindstrom C. Histopathological analysis of benign polyps in patients with carcinoma of the colon and rectum. Gut 1974; 15: 654-663
  • 3 Konishi F, Morson BC. Pathology of colorectal adenomas: a colonoscopic survey. J Clin Pathol 1982; 35: 830-841
  • 4 Vogelstein B, Fearon ER, Hamilton SR et al. Genetic alterations during colorectal-tumor development. N Engl J Med 1988; 319: 525-532
  • 5 Adachi M, Muto T, Okinaga K et al. Clinicopathologic features of the flat adenoma. Dis Colon Rectum 1991; 34: 981-986
  • 6 Wada R, Matsukuma S, Abe H et al. Histopathological studies of superficial-type early colorectal carcinoma. Cancer 1996; 77: 44-50
  • 7 Wolber RA, Owen DA. Flat adenomas of the colon. Hum Pathol 1991; 22: 70-74
  • 8 Muto T, Kamiya J, Sawada T et al. Small “flat adenoma” of the large bowel with special reference to its clinicopathologic features. Dis Colon Rectum 1985; 28: 847-851
  • 9 Shimoda T, Ikegami M, Fujisaki J et al. Early colorectal carcinoma with special reference to its development de novo. Cancer 1989; 64: 1138-1146
  • 10 Kudo S, Tamura S, Hirota S et al. The problem of de novo colorectal carcinoma. Eur J Cancer 1995; 31A: 1118-1120
  • 11 Lanspa SJ, Rouse J, Smyrk T et al. Epidemiologic characteristics of the flat adenoma of Muto. A prospective study. Dis Colon Rectum 1992; 35: 543-546
  • 12 Fujii T, Rembacken BJ, Dixon MF et al. Flat adenomas in the United Kingdom: are treatable cancers being missed?. Endoscopy 1998; 30: 437-443
  • 13 Fleischer DE, Goldberg SB, Browning TH et al. Detection and surveillance of colorectal cancer. JAMA 1989; 261: 580-585
  • 14 Winawer SJ, Zauber AG, Ho MN. The National Polyp Study Workgroup et al. Prevention of colorectal cancer by colonoscopic polypectomy. N Engl J Med 1993; 329: 1977-1981
  • 15 Rex DK. Maximizing detection of adenomas and cancers during colonoscopy. Am J Gastroenterol 2006; 101: 2866-2877
  • 16 Kim WH, Suh JH, Kim TI et al. Colorectal flat neoplasia. Dig Liver Dis 2003; 35: 165-171
  • 17 O’Brien MJ, Winawer SJ, Zauber AG et al. Flat adenomas in the National Polyp Study: is there increased risk for high-grade dysplasia initially or during surveillance?. Clin Gastroenterol Hepatol 2004; 2: 905-911
  • 18 Kil LeeS, Il KimT, Kwan ShinS et al. Comparison of the clinicopathologic features between flat and polypoid adenoma. Scand J Gastroenterol 2008; 43: 1116-1121
  • 19 Ferlitsch M, Reinhart K, Pramhas S et al. Sex-specific prevalence of adenomas, advanced adenomas, and colorectal cancer in individuals undergoing screening colonoscopy. JAMA 2011; 306: 1352-1358
  • 20 Weiss WHM. Darmkrebserkrankung in Österreich – Update 2008. J Gastroenterol Hepatol Erkrankungen 2008; 6: 19-22
  • 21 [Anonymous] The Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach, and colon: November 30 to December 1, 2002. Gastrointest Endosc 2003; 58: 3-43
  • 22 Jass JR, Sobin LH. World Health Organization ed. Histological typing of intestinal tumours. 2nd. edn. Berlin: Springer Verlag; 1989
  • 23 Leggett B, Whitehall V. Role of the serrated pathway in colorectal cancer pathogenesis. Gastroenterology 2010; 138: 2088-2100
  • 24 Kaminski MF, Regula J, Kraszewska E et al. Quality indicators for colonoscopy and the risk of interval cancer. N Engl J Med 2010; 362: 1795-1803
  • 25 Soetikno RM, Kaltenbach T, Rouse RV et al. Prevalence of nonpolypoid (flat and depressed) colorectal neoplasms in asymptomatic and symptomatic adults. JAMA 2008; 299: 1027-1035
  • 26 Kim J, Rami P, O’Toole J et al. Extent of prevalence and size of flat neoplasms in a heterogeneous population undergoing routine colorectal cancer screening. Colorectal Dis 2010; 12: 471-476
  • 27 Ignjatovic A, Saunders BP. Non-polypoid colorectal neoplasms are relatively common worldwide. Gastrointest Endosc Clin N Am 2010; 20: 417-429
  • 28 Kahi CJ, Hewett DG, Rex DK. Relationship of non-polypoid colorectal neoplasms to quality of colonoscopy. Gastrointest Endosc Clin N Am 2010; 20: 407-415
  • 29 Rembacken BJ, 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
  • 30 Saitoh Y, Waxman I, West AB et al. Prevalence and distinctive biologic features of flat colorectal adenomas in a North American population. Gastroenterology 2001; 120: 1657-1665
  • 31 Waye JD, Lewis BS, Frankel A et al. Small colon polyps. Am J Gastroenterol 1988; 83: 120-122
  • 32 Mitooka H, Fujimori T, Ohno S et al. Chromoscopy of the colon using indigo carmine dye with electrolyte lavage solution. Gastrointest Endosc 1992; 38: 373-374
  • 33 Bianco MA, Cipolletta L, Rotondano G et al. Prevalence of nonpolypoid colorectal neoplasia: an Italian multicenter observational study. Endoscopy 2010; 42: 279-285
  • 34 Rex DK, Petrini JL, Baron TH et al. Quality indicators for colonoscopy. Gastrointest Endosc 2006; 63: 16-28
  • 35 Adachi M, Okinaga K, Muto T. Flat adenoma of the large bowel: re-evaluation with special reference to central depression. Dis Colon Rectum 2000; 43: 782-787
  • 36 Kudo SE, Kashida H. Flat and depressed lesions of the colorectum. Clin Gastroenterol Hepatol 2005; 3: 33-36
  • 37 Kobayashi K, Sivak Jr MV. Flat adenoma: are western colonoscopists careful enough?. Endoscopy 1998; 30: 487-489
  • 38 Yasutomi M, Baba S, Hojo K et al. Japanese classification of colorectal carcinoma. Tokyo: Kanehara & Co; 1997
  • 39 Sawada T, Hojo K, Moriya Y. Colonoscopic management of focal and early colorectal carcinoma. Baillieres Clin Gastroenterol 1989; 3: 627-645
  • 40 Kudo S, Rubio CA, Teixeira CR et al. Pit pattern in colorectal neoplasia: endoscopic magnifying view. Endoscopy 2001; 33: 367-373
  • 41 Mitooka H, Fujimori T, Maeda S et al. Minute flat depressed neoplastic lesions of the colon detected by contrast chromoscopy using an indigo carmine capsule. Gastrointest Endosc 1995; 41: 453-459
  • 42 Saitoh Y, Obara T, Watari J et al. Invasion depth diagnosis of depressed type early colorectal cancers by combined use of videoendoscopy and chromoendoscopy. Gastrointest Endosc 1998; 48: 362-370
  • 43 Jaramillo E, Watanabe M, Slezak P et al. Flat neoplastic lesions of the colon and rectum detected by high-resolution video endoscopy and chromoscopy. Gastrointest Endosc 1995; 42: 114-122
  • 44 Kahi CJ, Anderson JC, Waxman I et al. High-definition chromocolonoscopy vs. high-definition white light colonoscopy for average-risk colorectal cancer screening. Am J Gastroenterol 2010; 105: 1301-1307