Assessing performance of screen readers in the National Health Service Breast Screening Programme (NHSBSP)
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KeywordsLearning Curve Rapid Expansion Recall Rate Interval Cancer Timely Method
Rapid expansion of the National Health Service Breast Screening Programme (NHSBSP) will result in many new readers undertaking the task of screen reading. A timely method for assessing performance (sensitivity and specificity), and preferably one that facilitates a steep learning curve, will be required. Since 1995, 90% of films have been double read at this unit. A manual record is kept of cancers detected through double reading and subsequent 3rd reader arbitration. The number of cases read and individuals' recall rates, when acting as the 1st reader, were obtained by running an annual co-writer report. A total of 150,344 women were screened between April 1995 and March 2001, resulting in the detection of 880 cancers. Sixty-six (7.5%) were detected following arbitration. There was variation both in recall to assessment rates and in the number of cases incorrectly returned to routine recall between readers. Prompt feedback of 'missed' cases allowed readers to modify their recall thresholds for particular mammographic abnormalities. If the cases had been single read the reader would have remained unaware of the 'miss' until the woman presented symptomatically with an interval cancer or the cancer was detected at the next screening round. It is recommended that the National Screening Committee review the policy of single versus double reading in the NHSBSP.