title: Diagnostic Reproducibility: What Happens When the Same Pathologist Interprets the Same Breast Biopsy Specimen at Two Points in Time?
abstract: BACKGROUND
  Surgeons may receive a different diagnosis when a breast biopsy is interpreted by a second pathologist. The extent to which diagnostic agreement by the same pathologist varies at two time points is unknown.
  
  
  METHODS
  Pathologists from eight U.S. states independently interpreted 60 breast specimens, one glass slide per case, on two occasions separated by ≥9 months. Reproducibility was assessed by comparing interpretations between the two time points; associations between reproducibility (intraobserver agreement rates); and characteristics of pathologists and cases were determined and also compared with interobserver agreement of baseline interpretations.
  
  
  RESULTS
  Sixty-five percent of invited, responding pathologists were eligible and consented; 49 interpreted glass slides in both study phases, resulting in 2940 interpretations. Intraobserver agreement rates between the two phases were 92% [95% confidence interval (CI) 88-95] for invasive breast cancer, 84% (95% CI 81-87) for ductal carcinoma-in-situ, 53% (95% CI 47-59) for atypia, and 84% (95% CI 81-86) for benign without atypia. When comparing all study participants' case interpretations at baseline, interobserver agreement rates were 89% (95% CI 84-92) for invasive cancer, 79% (95% CI 76-81) for ductal carcinoma-in-situ, 43% (95% CI 41-45) for atypia, and 77% (95% CI 74-79) for benign without atypia.
  
  
  CONCLUSIONS
  Interpretive agreement between two time points by the same individual pathologist was low for atypia and was similar to observed rates of agreement for atypia between different pathologists. Physicians and patients should be aware of the diagnostic challenges associated with a breast biopsy diagnosis of atypia when considering treatment and surveillance decisions.
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA. sljack@uw.edu.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Jackson
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Frederick
authors.affiliation: Program in Biostatistics and Biomathematics, Fred Hutchinson Cancer Research Center, Seattle, USA.
authors.forename: Margaret S
authors.initials: MS
authors.lastname: Pepe
authors.affiliation: Providence Cancer Center, Providence Health and Services Oregon, Portland, USA.|Departments of Medical Informatics and Clinical Epidemiology and Medicine, Oregon Health & Science University, Portland, USA.
authors.forename: Heidi D
authors.initials: HD
authors.lastname: Nelson
authors.affiliation: Department of Pathology and University of Vermont Cancer Center, University of Vermont, Burlington, VT, USA.
authors.forename: Donald L
authors.initials: DL
authors.lastname: Weaver
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, USA.
authors.forename: Kimberly H
authors.initials: KH
authors.lastname: Allison
authors.affiliation: Department of Family Medicine, Oregon Health & Science University, Portland, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Carney
authors.affiliation: Department of Family Medicine, University of Vermont, Burlington, USA.
authors.forename: Berta M
authors.initials: BM
authors.lastname: Geller
authors.affiliation: Department of Community and Family Medicine, The Dartmouth Institute for Health Policy and Clinical Practice, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, USA.|Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, USA.
authors.forename: Anna N A
authors.initials: AN
authors.lastname: Tosteson
authors.affiliation: Department of Community and Family Medicine, The Dartmouth Institute for Health Policy and Clinical Practice, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, USA.
authors.forename: Tracy
authors.initials: T
authors.lastname: Onega
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
authors.forename: Joann G
authors.initials: JG
authors.lastname: Elmore
mesh_terms: D000328:Adult; D001706:Biopsy; D001940:Breast / Q000473:pathology*; D000071060:Breast Density; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology*; D002983:Clinical Competence; D005260:Female; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D000072142:Pathologists; D015203:Reproducibility of Results; D013997:Time Factors; D014481:United States