Interobserver agreement and accuracy among international experts with probe-based confocal laser endomicroscopy in predicting colorectal neoplasia

Background and study aims: A recently developed probe-based, confocal laser endomicroscopy (pCLE) system provides images of surface colonic epithelium in vivo during any endoscopy. Our objective was to assess interobserver agreement, sensitivity, specificity, and overall accuracy in the diagnosis of neoplasia using pCLE.

Patients and methods: 53 patients undergoing surveillance and screening colonoscopies were enrolled. A total of 75 lesions, were detected and all were inspected by pCLE prior to sampling or polypectomy. Intravenous fluorescein was used to optimize tissue contrast. Three pCLE users, blinded to histopathologic and endoscopic findings, reviewed the set of video sequences for crypt architecture, vessel architecture, and colorectal neoplasia diagnosis. Histopathologic diagnosis from the corresponding biopsies was the reference gold standard.

Results: Of the 75 colorectal lesions, 50 were neoplastic and 25 non-neoplastic. Interobserver agreement was moderate to good for the classification of neoplasia (kappa 0.55, 78 % pairwise agreement), and moderate for vessel architecture (kappa 0.41, 67 % pairwise agreement) and crypt architecture (kappa 0.49, 69 % pairwise agreement). In distinguishing between neoplastic and non-neoplastic lesions, sensitivity, specificity, and accuracy were 76 %, 72 % and 75 %, respectively. When videos of good or excellent quality only were considered, interobserver agreement for classification of neoplasia was higher (kappa 0.83, 92 % pairwise agreement), as were sensitivity (88 %), specificity (89 %), and accuracy (88 %).

Conclusion: An international collaboration group had moderate to good interobserver agreement using a pCLE system to predict neoplasia, which is acceptable for this study.

References

• 1 American Cancer Society .Cancer Facts & Figures 2008. Atlanta; 2008
• 2 Rex D K, Johnson D A, Anderson J C. et al . American College of Gastroenterology guidelines for colorectal cancer screening 2009 [corrected].  Am J Gastroenterol. 2009;  104 739-750
• 3 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
• 4 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
• 5 East J E, Guenther T, Saunders B P. Novel approaches in colorectal endoscopy: what do we need biopsies for?.  Pathology, research and practice. 2008;  204 459-467
• 6 Hurlstone D P, Tiffin N, Brown S R. et al . In vivo confocal laser scanning chromo-endomicroscopy of colorectal neoplasia: changing the technological paradigm.  Histopathology. 2008;  52 417-426
• 7 Wallace M B, Fockens P. Probe-based confocal laser endomicroscopy.  Gastroenterology. 2009;  136 1509-1513
• 8 Buchner A M, Shahid M W, Heckman M G. Comparison of probe based confocal laser endomicroscopy with virtual chromoendoscopy for classification of colon polyps.  Gastroenterology. In press 2010; 
• 9 Meining A, Saur D, Bajbouj M. et al . In vivo histopathology for detection of gastrointestinal neoplasia with a portable, confocal miniprobe: an examiner blinded analysis.  Clin Gastroenterol Hepatol. 2007;  5 1261-1267
• 10 Landis J R, Koch G G. The measurement of observer agreement for categorical data.  Biometrics. 1977;  33 159-174
• 11 Watanabe O, Ando T, Maeda O. et al . Confocal endomicroscopy in patients with ulcerative colitis.  J Gastroenterol Hepatol. 2008;  23 Suppl 2 286-290
• 12 Hurlstone D P, Thomson M, Brown S. et al . Confocal endomicroscopy in ulcerative colitis: differentiating dysplasia-associated lesional mass and adenoma-like mass.  Clin Gastroenterol Hepatol. 2007;  5 1235-1241
• 13 Pohl H, Rosch T, Vieth M. et al . Miniprobe confocal laser microscopy for the detection of invisible neoplasia in patients with Barrett’s oesophagus.  Gut. 2008;  57 1648-1653
• 14 Hurlstone D P, Baraza W, Brown S. et al . In vivo real-time confocal laser scanning endomicroscopic colonoscopy for the detection and characterization of colorectal neoplasia.  Br J Surg. 2008;  95 636-645
• 15 Iwamoto Y, Itoyama T, Yasuda K. et al . Photodynamic DNA strand breaking activities of acridine compounds.  Biol Pharmaceut Bull. 1993;  16 1244-1247
• 16 Wallace M B, Meining A, Canto M I. et al . Safety of intravenous fluorescein for confocal laser endomicroscopy in the gastrointestinal tract.  Aliment Pharmacol Ther. In press 2010; 
• 17 Wallace M, Buchner A, Becker V, Meining A. Determination of the optimal fluorescein dose of probe-based confocal laser endomicroscopy in colonic imaging.  Gastrointest Endosc. 2009;  69 AB375
• 18 Wallace M. Leeuwenhoek meets Kussmaul: the evolution of endoscopist to endo-pathologist.  Gastroenterology. 2006;  131 347-349