Effect of using the same vs different order for second readings of screening mammograms on rates of breast cancer detection: a randomized clinical trial

Research output: Contribution to journalArticlepeer-review


  • Sian Taylor-Phillips
  • Matthew G Wallis
  • David Jenkinson
  • Victor Adekanmbi
  • Helen Parsons
  • Janet Dunn
  • Nigel Stallard
  • Ala Szczepura
  • Olive Kearins
  • Alison Duncan
  • Sue Hudson
  • Aileen Clarke

Colleges, School and Institutes

External organisations

  • Warwick University
  • Cambridge Breast Unit, Cambridge Universities NHS Foundation Trust and NIHR Cambridge Biomedical Research Centre, Cambridge, United Kingdom.
  • Screening QA Service (Midland & East), Seaton House, City Link, Nottingham, United Kingdom.
  • Warwickshire, Solihull and Coventry Breast Screening Service, University Hospitals Coventry and Warwickshire, Coventry, United Kingdom.
  • Peel & Schriek Consulting Limited, London, United Kingdom.


IMPORTANCE: Interpreting screening mammograms is a difficult repetitive task that can result in missed cancers and false-positive recalls. In the United Kingdom, 2 film readers independently evaluate each mammogram to search for signs of cancer and examine digital mammograms in batches. However, a vigilance decrement (reduced detection rate with time on task) has been observed in similar settings.

OBJECTIVE: To determine the effect of changing the order for the second film reader of batches of screening mammograms on rates of breast cancer detection.

DESIGN, SETTING, AND PARTICIPANTS: A multicenter, double-blind, cluster randomized clinical trial conducted at 46 specialized breast screening centers from the National Health Service Breast Screening Program in England for 1 year (all between December 20, 2012, and November 3, 2014). Three hundred sixty readers participated (mean, 7.8 readers per center)-186 radiologists, 143 radiography advanced practitioners, and 31 breast clinicians, all fully qualified to report mammograms in the NHS breast screening program.

INTERVENTIONS: The 2 readers examined each batch of digital mammograms in the same order in the control group and in the opposite order to one another in the intervention group.

MAIN OUTCOMES AND MEASURES: The primary outcome was cancer detection rate; secondary outcomes were rates of recall and disagreements between readers.

RESULTS: Among 1,194,147 women (mean age, 59.3; SD, 7.49) who had screening mammograms (596,642 in the intervention group; 597,505 in the control group), the images were interpreted in 37,688 batches (median batch size, 35; interquartile range [IQR]; 16-46), with each reader interpreting a median of 176 batches (IQR, 96-278). After completion of all subsequent diagnostic tests, a total of 10,484 cases (0.88%) of breast cancer were detected. There was no significant difference in cancer detection rate with 5272 cancers (0.88%) detected in the intervention group vs 5212 cancers (0.87%) detected in the control group (difference, 0.01% points; 95% CI, -0.02% to 0.04% points; recall rate, 24,681 [4.14%] vs 24,894 [4.17%]; difference, -0.03% points; 95% CI, -0.10% to 0.04% points; or rate of reader disagreements, 20,471 [3.43%] vs 20,793 [3.48%]; difference, -0.05% points; 95% CI, -0.11% to 0.02% points).

CONCLUSIONS AND RELEVANCE: Interpretation of batches of mammograms by qualified screening mammography readers using a different order vs the same order for the second reading resulted in no significant difference in rates of detection of breast cancer.

TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN46603370.


Original languageEnglish
Pages (from-to)1956-65
Number of pages10
JournalJAMA The Journal of the American Medical Association
Issue number18
Publication statusPublished - 10 May 2016


  • Attention, Breast Neoplasms, Double-Blind Method, England, Female, Humans, Logistic Models, Mammography, Middle Aged, Observer Variation, Radiology, Sample Size, Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't