title: Consistency in the observation of features used to classify duct carcinoma in situ (DCIS) of the breast.
abstract: OBJECTIVE
  To determine interobserver and intra-observer agreement in the assessment of cytological grade and intraduct necrosis in pure duct carcinoma in situ (DCIS) of the breast.
  
  
  METHODS
  Sixty unselected cases with illustrated diagnostic criteria were circulated to 19 practising histopathologists.
  
  
  RESULTS
  Overall agreement was moderate for cytological grade in three categories: 71% agreement; weighted kappa (kappa w), 0.36; intraduct necrosis in three categories (absent, present, extensive): 76% agreement; kappa w, 0.57; and the Van Nuys classification system: 73% agreement; kappa w, 0.48. Agreement was no better among observers participating in the National External Quality Assurance Programme. Intra-observer agreement for cytological assessment (69.6% agreement; kappa w, 0.52) and intraduct necrosis (68.3% agreement; kappa w, 0.48) was moderate, suggesting that individual variation rather than precision of criteria contributes to the lack of agreement.
  
  
  CONCLUSIONS
  Moderate agreement on observations can be achieved by non-specialist pathologists, with better agreement on necrosis than cytological grade. There was evidence of consistent individual bias towards over or under scoring cytological grade, which could be corrected with adequate and prompt feedback.
authors.affiliation: Department of Pathology, University of Wales College of Medicine, Cardiff, UK. ag.dj@virgin.net
authors.forename: A G
authors.initials: AG
authors.lastname: Douglas-Jones
authors.forename: J M
authors.initials: JM
authors.lastname: Morgan
authors.forename: M A
authors.initials: MA
authors.lastname: Appleton
authors.forename: R L
authors.initials: RL
authors.lastname: Attanoos
authors.forename: A
authors.initials: A
authors.lastname: Caslin
authors.forename: C S
authors.initials: CS
authors.lastname: Champ
authors.forename: M
authors.initials: M
authors.lastname: Cotter
authors.forename: N S
authors.initials: NS
authors.lastname: Dallimore
authors.forename: A
authors.initials: A
authors.lastname: Dawson
authors.forename: R W
authors.initials: RW
authors.lastname: Fortt
authors.forename: A P
authors.initials: AP
authors.lastname: Griffiths
authors.forename: M
authors.initials: M
authors.lastname: Hughes
authors.forename: P A
authors.initials: PA
authors.lastname: Kitching
authors.forename: C
authors.initials: C
authors.lastname: O'Brien
authors.forename: A M
authors.initials: AM
authors.lastname: Rashid
authors.forename: D
authors.initials: D
authors.lastname: Stock
authors.forename: A
authors.initials: A
authors.lastname: Verghese
authors.forename: D W
authors.initials: DW
authors.lastname: Williams
authors.forename: N W
authors.initials: NW
authors.lastname: Williams
authors.forename: S
authors.initials: S
authors.lastname: Williams
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D002278:Carcinoma in Situ / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology*; D005260:Female; D006801:Humans; D015588:Observer Variation; D015203:Reproducibility of Results; D013223:Statistics as Topic