COMPARISON OF SINGLE READING WITH DOUBLE READING OF MAMMOGRAMS, AND CHANGE IN EFFECTIVENESS WITH EXPERIENCE

In the prevalence round of screening for breast cancer at a single cen tre, the benefit of the second radiological report has been assessed u sing data from 33 734 women, their screening results and knowledge of the interval cancers. The service was set up under the UK National Bre ast Screening Programme, and the data show evidence of learning by bot h individuals and the team as a whole. Of the 269 cancers detected by screening 33 would not have been diagnosed if the only report availabl e had been the first. The recall recommendation rate associated with t he first report was 6.9% and 236 cancers were detected. The recall rec ommendation rate associated with all queries of all the reports was 10 % (3354 queries). Had these 3354 queries all been investigated (instea d of the 1423 actually recalled) only a further three cancers would ha ve been detected. Sensitivity of the programme as a whole was substant ially better than that of individual radiologists, while the specifici ty was maintained. The decision pathway by which recalls were agreed b etween the two radiologists resulted in a low recall rate (4.2%) for t he programme as a whole, and is a critical factor in gaining the benef it of the improved sensitivity without a concomitant deterioration in the specificity. With the passage through the prevalent round, recall rates steadily fell, the malignant to benign biopsy ratio improved and sensitivity increased. The second radiological report yielded 14% add itional cancers diagnosed and contributed very significantly to good s ensitivity and so to the effectiveness of screening. Economic analysis of the results will be reported in a further paper.