title: Accuracy and concordance of endocytoscopic atypia for the diagnosis of gastric cancer.
abstract: OBJECTIVE
  High-grade atypia demonstrated by endocytoscopy may be a key criterion for the diagnosis of gastric cancer. We therefore sought to verify whether endocytoscopic atypia can provide satisfactory levels of diagnostic accuracy and concordance among trainee and expert endoscopists.
  
  
  METHODS
  A total of 100 lesions evaluated by endocytoscopy and histopathology were enrolled to create an endocytoscopic image catalog (44 early cancers, 10 low-grade adenomas, 46 non-neoplastic lesions). Four endoscopists (two trainees and two experts) independently reviewed the catalog images and evaluated each of them for the presence or absence of endocytoscopic atypia. High-grade endocytoscopic atypia, as a criterion for cancer diagnosis, was defined as the consistent observation of any of the following features: lumen absence, lumen fusion, and irregular nuclei showing the three typical features (heterogeneous shape, swelling, and disarrangement).
  
  
  RESULTS
  High-grade endocytoscopic atypia was observed in 78 %, 18 %, and 4 % of cancers, adenomas, and non-neoplastic lesions, respectively. The sensitivity, specificity, accuracy, and positive and negative predictive values for cancer diagnosis by endocytoscopy were 78.4 %, 93.3 %, 87.3 %, 85.4 %, and 87.3 %, respectively. The concordance rate for the results of high-grade endocytoscopic atypia was good among the four endoscopists (κ value 0.682). No significant difference in diagnostic accuracy or concordance was observed between trainee and expert endoscopists.
  
  
  CONCLUSIONS
  Using the defined high-grade atypia as a diagnostic criterion of cancer, endocytoscopy provided a satisfactory level of accuracy and concordance for the diagnosis of early gastric cancer, regardless of endoscopic expertise.
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kaise
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Kimura
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Nomura
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Kuribayashi
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kikuchi
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Iizuka
authors.affiliation: Department of Pathology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohkura
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000236:Adenoma / Q000473:pathology*; D002467:Cell Nucleus / Q000473:pathology; D002983:Clinical Competence; D004396:Coloring Agents; D005773:Gastroscopy / Q000379:methods; D005840:Gentian Violet; D006801:Humans; D008751:Methylene Blue; D015588:Observer Variation; D011237:Predictive Value of Tests; D013274:Stomach Neoplasms / Q000473:pathology*
chemical_list: D004396:Coloring Agents; D005840:Gentian Violet; D008751:Methylene Blue