BREAST Discrepant screening mammography assessments at blinded and non-blinded double reading: impact of arbitration by a third reader on screening outcome Elisabeth G. Klompenhouwer 1 & Adri C. Voogd 2,3 & Gerard J. den Heeten 4,5 & Luc J. A. Strobbe 6 & Vivianne C. Tjan-Heijnen 7 & Mireille J. M. Broeders 4,8 & Lucien E. M. Duijm 9 Received: 21 December 2014 /Revised: 16 February 2015 /Accepted: 5 March 2015 # European Society of Radiology 2015 Abstract Objectives To determine the value of adding a third reader for arbitration of discrepant screening mammography assessments. Methods We included a consecutive series of 84,927 digital screening mammograms, double read in a blinded or non- blinded fashion. Arbitration was retrospectively performed by a third screening radiologist. Two years’ follow-up was performed. Results Discrepant readings comprised 57.2 % (830/1452) and 29.1 % (346/1188) of recalls at blinded and non-blinded double readings, respectively. At blinded double reading, ar- bitration would have decreased recall rate (3.4 to 2.2 %, p< 0.001) and programme sensitivity (83.2 to 76.0 %, p=0.013), would not have influenced the cancer detection rate (CDR; 7.5 to 6.8 per 1,000 screens, p=0.258) and would have increased the positive predictive value of recall (PPV; 22.3 to 31.2 %, p <0.001). At non-blinded double reading, arbitration would have decreased recall rate (2.8 to 2.3 %, p<0.001) and in- creased PPV (23.2 to 27.5 %, p=0.021), but would not have affected CDR (6.6 to 6.3 per 1,000 screens, p=0.604) and programme sensitivity (76.0 to 72.7 %, p=0.308). Conclusion Arbitration of discrepant screening mammogra- phy assessments is a good tool to improve recall rate and PPV, but is not desirable as it reduces the programme sensi- tivity at blinded double reading. Key points • Blinded double reading results in higher programme sensi- tivity than non-blinded reading. • Discrepant readings occur more often at blinded compared to non-blinded reading. • Arbitration of discrepant readings reduces the recall rate and PPV. • Arbitration would reduce the programme sensitivity at blinded double reading. Keywords Mammography . Breast neoplasms . Mass screening . Sensitivity . Early detection of cancer Introduction Reading strategies of organized screening programmes can influence the main performance parameters in a sub- stantial way and therefore can influence what is often * Elisabeth G. Klompenhouwer elisabethgenevieve@hotmail.com 1 Department of Radiology, Catharina Hospital, PO Box 1350, 5602 ZA Eindhoven, The Netherlands 2 Department of Research, Comprehensive Cancer Centre the Netherlands (IKNL), PO Box 231, 5600 AE Eindhoven, The Netherlands 3 Department of Epidemiology, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands 4 Dutch Reference Centre for Screening, PO Box 231, 5600 AE Nijmegen, The Netherlands 5 Department of Radiology, Biomechanical Engineering and Physics, Academic Medical Centre Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands 6 Department of Surgical Oncology, Canisius Wilhelmina Hospital, PO Box 9015, 6500 GS Nijmegen, The Netherlands 7 Department of Medical Oncology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ Maastricht, The Netherlands 8 Department for Health Evidence, Radboud University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands 9 Department of Radiology, Canisius Wilhelmina Hospital, PO Box 9015, 6500 GS Nijmegen, The Netherlands Eur Radiol DOI 10.1007/s00330-015-3711-6