title: Mammography screening using independent double reading with consensus: is there a potential benefit for computer-aided detection?
abstract: BACKGROUND
  Double reading improves the cancer detection rate in mammography screening. Single reading with computer-aided detection (CAD) has been considered to be an alternative to double reading. Little is known about the potential benefit of CAD in breast cancer screening with double reading.
  
  
  OBJECTIVE
  To compare prospective independent double reading of screen-film (SFM) and full-field digital (FFDM) mammography in population-based screening with retrospective standalone CAD performance on the baseline mammograms of the screen-detected cancers and subsequent cancers diagnosed during the follow-up period.
  
  
  METHODS
  The study had ethics committee approval. A 5-point rating scale for probability of cancer was used for 23,923 (SFM = 16,983; FFDM = 6940) screening mammograms. Of 208 evaluable cancers, 104 were screen-detected and 104 were subsequent (44 interval and 60 next screening round) cancers. Baseline mammograms of subsequent cancers were retrospectively classified in consensus without information about cancer location, histology, or CAD prompting as normal, non-specific minimal signs, significant minimal signs, and false-negatives. The baseline mammograms of the screen-detected cancers and subsequent cancers were evaluated by CAD. Significant minimal signs and false-negatives were considered 'actionable' and potentially diagnosable if correctly prompted by CAD.
  
  
  RESULTS
  CAD correctly marked 94% (98/104) of the baseline mammograms of the screen-detected cancers (SFM = 95% [61/64]; FFDM = 93% [37/40]), including 96% (23/24) of those with discordant interpretations. Considering only those baseline examinations of subsequent cancers prospectively interpreted as normal and retrospectively categorized as 'actionable', CAD input at baseline screening had the potential to increase the cancer detection rate from 0.43% to 0.51% (P = 0.13); and to increase cancer detection by 16% ([104 + 17]/104) and decrease interval cancers by 20% (from 44 to 35).
  
  
  CONCLUSIONS
  CAD may have the potential to increase cancer detection by up to 16%, and to reduce the number of interval cancers by up to 20% in SFM and FFDM screening programs using independent double reading with consensus review. The influence of true- and false-positive CAD marks on decision-making can, however, only be evaluated in a prospective clinical study.
authors.affiliation: Department of Radiology, Ullevaal University Hospital, University of Oslo, Norway. PERSKA@ous-hf.no
authors.forename: Per
authors.initials: P
authors.lastname: Skaane
authors.forename: Ashwini
authors.initials: A
authors.lastname: Kshirsagar
authors.forename: Solveig
authors.initials: S
authors.lastname: Hofvind
authors.forename: Gunnar
authors.initials: G
authors.lastname: Jahr
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Castellino
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D032921:Consensus; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008327:Mammography / Q000379:methods*; D008403:Mass Screening; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies