High resolution microendoscopy for classification of colorectal polyps

Background and study aims: It can be difficult to distinguish adenomas from benign polyps during routine colonoscopy. High resolution microendoscopy (HRME) is a novel method for imaging colorectal mucosa with subcellular detail. HRME criteria for the classification of colorectal neoplasia have not been previously described. Study goals were to develop criteria to characterize HRME images of colorectal mucosa (normal, hyperplastic polyps, adenomas, cancer) and to determine the accuracy and interobserver variability for the discrimination of neoplastic from non-neoplastic polyps when these criteria were applied by novice and expert microendoscopists.

Methods: Two expert pathologists created consensus HRME image criteria using images from 68 patients with polyps who had undergone colonoscopy plus HRME. Using these criteria, HRME expert and novice microendoscopists were shown a set of training images and then tested to determine accuracy and interobserver variability.

Results: Expert microendoscopists identified neoplasia with sensitivity, specificity, and accuracy of 67 % (95 % confidence interval [CI] 58 % – 75 %), 97 % (94 % – 100 %), and 87 %, respectively. Nonexperts achieved sensitivity, specificity, and accuracy of 73 % (66 % – 80 %), 91 % (80 % – 100 %), and 85 %, respectively. Overall, neoplasia were identified with sensitivity 70 % (65 % – 76 %), specificity 94 % (87 % – 100 %), and accuracy 85 %. Kappa values were: experts 0.86; nonexperts 0.72; and overall 0.78.

Conclusions: Using the new criteria, observers achieved high specificity and substantial interobserver agreement for distinguishing benign polyps from neoplasia. Increased expertise in HRME imaging improves accuracy. This low-cost microendoscopic platform may be an alternative to confocal microendoscopy in lower-resource or community-based settings.

Clinical trial registration no. NCT01384240

• References

• 1 Ries LA, Wingo PA, Miller DS et al. The annual report to the nation on the status of cancer, 1973–1997, with a special section on colorectal cancer. Cancer 2000; 88: 2398-424
• 2 U.S. Preventive Services Task Force. Screening for colorectal cancer: U.S. Preventive Services Task Force recommendation statement. AHRQ Publication 08–05124-EF-3. Rockville, Maryland, USA: Agency for Healthcare Research and Quality; 10/2008
• 3 Seeff LC, Richards TB, Shapiro JA et al. How many endoscopies are performed for colorectal cancer screening? Results from CDC’s survey of endoscopic capacity. Gastroenterology 2004; 127: 1670-1677
• 4 Lieberman D, Moravec M, Holub J et al. Polyp size and advanced histology in patients undergoing colonoscopy screening: implications for CT colonography. Gastroenterology 2008; 135: 1100-1105
• 5 Diamond SJ, Enestvedt BK, Jiang Z et al. Adenoma detection rate increases with each decade of life after 50 years of age. Gastrointest Endosc 2011; 74: 135-140
• 6 Kim DoH, Lim SW. Analysis of delayed postpolypectomy bleeding in a colorectal clinic. J Korean Soc Coloproctol 2011; 27: 13-16
• 7 Buddingh KT, Herngreen T, Haringsma J et al. Location in the right hemi-colon is an independent risk factor for delayed post-polypectomy hemorrhage: a multi-center case-control study. Am J Gastroenterol 2011; 106: 1119-1124
• 8 Rabeneck L, Paszat LF, Hilsden RJ et al. Bleeding and perforation after outpatient colonoscopy and their risk factors in usual clinical practice. Gastroenterology 2008; 135: 1899-1906
• 9 Butterly LF, Chase MP, Pohl H et al. Prevalence of clinically important histology in small adenomas. Clin Gastroenterol Hepatol 2006; 4: 343-348
• 10 Shahid MW, Buchner AM, Heckman MG et al. Diagnostic accuracy of probe-based confocal laser endomicroscopy and narrow band imaging for small colorectal polyps: a feasibility study. Gastroenterology 2012; 107: 231-239
• 11 Muldoon TJ, Pierce MC, Nida DL et al. Subcellular-resolution molecular imaging within living tissue by fiber microendoscopy. Opt Express 2007; 15: 16413-16423
• 12 Muldoon TJ, Anandasabapathy S, Maru D et al. High-resolution imaging in Barrett’s esophagus: a novel, low-cost endoscopic microscope. Gastrointest Endosc 2008; 68: 737-744
• 13 Pierce M, Dihua Y, Richards-Kortum R. High-resolution fiber-optic microendoscopy for in situ cellular imaging. J Vis Exp 2011; 47: e2306 DOI: 10.3791/2306.
• 14 Hamilton SR, Bosman FT, Boffetta P et al. Carcinoma of the colon and rectum. In: et al. Bosman FT, Carneiro F, Hruban RH, (eds) WHO classification of tumours of the digestive system. 4th. edn. Lyon: IARC; 2010
• 15 Fleiss JL. Statistical methods for rates and proportions. 3rd. edn. New York: John Wiley & Sons; 2003
• 16 Posner KL, Sampson PD, Caplan RA et al. Measuring interrater reliability among multiple raters – an example of methods for nominal data. Stat Med 1990; 9: 1103-1115
• 17 Landis JR, Koch GG. Measurement of observer agreement for categorical data. Biometrics 1977; 33: 159-174
• 18 Block DA, Kraemer HC. 2×2 kappa coefficients: measures of agreement or association. Biometrics 1989; 45: 269-287
• 19 Lee MH, Vila PM, Polydorides AD et al. Diagnostic accuracy of a novel low cost microendoscope for the detection of Barrett’s neoplasia: a prospective, single-center trial. Gastroenterology 2012; 142: 335
• 20 Kiesslich R, Burg J, Vieth M et al. Confocal laser endoscopy for diagnosing intraepithelial neoplasias and colorectal cancer in vivo. Gastroenterology 2004; 127: 706-713
• 21 Kulper T, Van den Broek FJC, Van Eeden S et al. New classification for probe-based confocal laser endomicroscopy in the colon. Endoscopy 2011; 43: 1076-1081
• 22 Gomez V, Buchner AM, Dekker E et al. Interobserver agreement and accuracy among international experts with probe-based confocal laser endomicroscopy in predicting colorectal neoplasia. Endoscopy 2010; 42: 286-291
• 23 Kulper T, Kiesslich R, Ponsioen C et al. The learning curve, accuracy, and interobserver agreement of endoscope-based confocal laser endomicroscopy for the differentiation of colorectal lesions. Gastrointest Endosc 2012; 75: 1211-1217
• 24 De Palma GD, Staibano S, Siciliano S et al. In vivo characterisation of superficial colorectal neoplastic lesions with high-resolution probe-based confocal laser endomicroscopy in combination with video-mosaicing: a feasibility study to enhance routine endoscopy. Dig Liver Dis 2010; 42: 791-797
• 25 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
• 26 Marion JF, Waye JD, Present DH et al. Chromoendoscopy-targeted biopsies are superior to standard colonoscopic surveillance for detecting dysplasia in inflammatory bowel disease patients: a prospective endoscopic trial. Am J Gastroenterol 2008; 103: 2342-2349
• 27 Hassan C, Pickhardt PJ, Rex DK. A resect and discard strategy would improve cost-effectiveness of colorectal cancer screening. Clin Gastroenterol Hepatol 2010; 8: 865-869