title: External validation of a classification for methylene blue magnification chromoendoscopy in premalignant gastric lesions.
abstract: BACKGROUND
  Conventional endoscopy has low sensitivity, specificity, and interobserver agreement for the diagnosis of gastric atrophy, intestinal metaplasia, and dysplasia. Magnification chromoendoscopy (ME) may optimize the evaluation of premalignant gastric lesions.
  
  
  OBJECTIVE
  As part of a multicenter trial, we aimed at validating a previously proposed classification for gastric methylene blue ME at a different center. SETTING, PATIENTS, AND INTERVENTIONS: A sample of patients (n = 42) with previously diagnosed chronic atrophic gastritis with or without intestinal metaplasia underwent ME (Pentax EG-3430Z) with 1% methylene blue by 2 endoscopists.
  
  
  METHODS
  A simplified version of a previously published ME classification (group I, group II [further divided into subgroups IIE and IIF], and group III) was used for macroscopic lesions (n = 203) with Sydney-Houston and Vienna classifications being used for histologic analysis (n = 479 biopsy specimens).
  
  
  CONCLUSIONS
  Excellent reproducibility (wK = 0.92 [95% CI, 0.88-0.96]) was observed for classification in groups and substantial reproducibility (wK = 0.78 [95% CI, 0.72-0.84]) was found for classification in subgroups. Global validity was 82% (range 78%-86%), showing no false negatives (sensitivity of 100% [1/1 biopsy]) and a very low rate of false positives (specificity 99% [297/299 biopsies]) for dysplasia detection.
  
  
  CONCLUSIONS
  This classification for methylene blue ME was highly reproducible and valid for the diagnosis of premalignant gastric lesions when used in a center different from that involved in its conception. Despite requiring an unconventional endoscope and a longer procedure, these results could reinforce ME as a valuable technique in the surveillance of patients at risk for gastric cancer.
authors.affiliation: Gastroenterology Department, Coimbra University Hospital, Coimbra, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Areia
authors.forename: Pedro
authors.initials: P
authors.lastname: Amaro
authors.forename: Mário
authors.initials: M
authors.lastname: Dinis-Ribeiro
authors.forename: Maria Augusta
authors.initials: MA
authors.lastname: Cipriano
authors.forename: Carol
authors.initials: C
authors.lastname: Marinho
authors.forename: Altamiro
authors.initials: A
authors.lastname: Costa-Pereira
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopes
authors.forename: Luís
authors.initials: L
authors.lastname: Moreira-Dias
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Romãozinho
authors.forename: Hermano
authors.initials: H
authors.lastname: Gouveia
authors.forename: Diniz
authors.initials: D
authors.lastname: Freitas
authors.forename: Maximino Correia
authors.initials: MC
authors.lastname: Leitão
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D005753:Gastric Mucosa / Q000473:pathology; D005757:Gastritis, Atrophic / Q000175:diagnosis / Q000473:pathology*; D020699:Gastroscopes; D005773:Gastroscopy / Q000145:classification / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007150:Immunohistochemistry; D008297:Male; D008751:Methylene Blue; D008875:Middle Aged; D011230:Precancerous Conditions / Q000175:diagnosis / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000145:classification / Q000379:methods*; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000473:pathology*
chemical_list: D008751:Methylene Blue