title: Blinded double reading yields a higher programme sensitivity than non-blinded double reading at digital screening mammography: a prospected population based study in the south of The Netherlands.
abstract: OBJECTIVE
  To prospectively determine the screening mammography outcome at blinded and non-blinded double reading in a biennial population based screening programme in the south of the Netherlands.
  
  
  METHODS
  We included a consecutive series of 87,487 digital screening mammograms, obtained between July 2009 and July 2011. Screening mammograms were double read in either a blinded (2nd reader was not informed about the 1st reader's decision) or non-blinded fashion (2nd reader was informed about the 1st reader's decision). This reading strategy was alternated on a monthly basis. Women with discrepant readings between the two radiologists were always referred for further analysis. During 2 years follow-up, we collected the radiology reports, surgical correspondence and pathology reports of all referred women and interval breast cancers.
  
  
  RESULTS
  Respectively 44,491 and 42,996 screens had been read either in a blinded or non-blinded fashion. Referral rate (3.3% versus 2.8%, p<0.001) and false positive rate (2.6% versus 2.2%, p=0.002) were significantly higher at blinded double reading whereas the cancer detection rate per 1000 screens (7.4 versus 6.5, p=0.14) and positive predictive value of referral (22% versus 23%, p=0.51) were comparable. Blinded double reading resulted in a significantly higher programme sensitivity (83% versus 76%, p=0.01). Per 1000 screened women, blinded double reading would yield 0.9 more screen detected cancers and 0.6 less interval cancers than non-blinded double reading, at the expense of 4.4 more recalls.
  
  
  CONCLUSIONS
  We advocate the use of blinded double reading in order to achieve a better programme sensitivity, at the expense of an increased referral rate and false positive referral rate.
authors.affiliation: Department of Radiology, Catharina Hospital, PO Box 1350, 5602 ZA Eindhoven, The Netherlands. Electronic address: elisabethgenevieve@hotmail.com.
authors.forename: Elisabeth G
authors.initials: EG
authors.lastname: Klompenhouwer
authors.affiliation: Comprehensive Cancer Centre South (IKZ)/Eindhoven Cancer Registry, PO Box 231, 5600 AE Eindhoven, The Netherlands; Department of Epidemiology, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands.
authors.forename: Adri C
authors.initials: AC
authors.lastname: Voogd
authors.affiliation: National Expert and Training Centre for Breast Cancer Screening, PO Box 6873, 6503 GJ Nijmegen, The Netherlands.
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: den Heeten
authors.affiliation: Department of Surgical Oncology, Canisius Wilhelmina Hospital, PO Box 9015, 6500 GS Nijmegen, The Netherlands.
authors.forename: Luc J A
authors.initials: LJ
authors.lastname: Strobbe
authors.affiliation: Department of Pathology, Canisius Wilhelmina Hospital, PO Box 9015, 6500 GS Nijmegen, The Netherlands.
authors.forename: Anton F J
authors.initials: AF
authors.lastname: de Haan
authors.affiliation: Department of Pathology, Canisius Wilhelmina Hospital, PO Box 9015, 6500 GS Nijmegen, The Netherlands.
authors.forename: Carla A
authors.initials: CA
authors.lastname: Wauters
authors.affiliation: National Expert and Training Centre for Breast Cancer Screening, PO Box 6873, 6503 GJ Nijmegen, The Netherlands; Department for Health Evidence, Radboud University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Mireille J M
authors.initials: MJ
authors.lastname: Broeders
authors.affiliation: Department of Radiology, Canisius Wilhelmina Hospital, PO Box 9015, 6500 GS Nijmegen, The Netherlands.
authors.forename: Lucien E M
authors.initials: LE
authors.lastname: Duijm
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D004311:Double-Blind Method; D055088:Early Detection of Cancer / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008327:Mammography / Q000379:methods*; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015588:Observer Variation; D012017:Referral and Consultation / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity
keywords: Breast cancer; Double reading; Positive predictive value; Referral rate; Screening mammography; Sensitivity