Added Value of Prereading Screening Mammograms for Breast Cancer by Radiologic Technologists on Early Screening Outcomes.

Background In the Dutch breast cancer screening program, mammograms are preread by technologists to identify possible abnormalities, leading to "warning signals" (an audible and visual alert if the technologist observed an abnormality suspicious for cancer) for radiologists. The best moment to present these warning signals is unknown. Purpose To determine the effect that blinding of technologists' warning signals has on radiologists' early screening outcome measures during interpretation of mammograms. Materials and Methods In this prospective study from September 2017 to May 2019, on alternating months, radiologists were either blinded or nonblinded to the warning signals of the technologist when interpreting screening mammograms for breast cancer. All discrepancies between radiologists and technologists were reviewed during quality assurance sessions every 6 weeks, which could result in secondary recalls. The outcome measures of this study were recall rate, cancer detection rate, and positive predictive value of recall. A χ2 test was used to test for differences between the two groups. Results During the study period, 109 596 women (mean age, 62 years ± 7 [standard deviation]), including 53 291 in the blinded and 56 305 in the nonblinded groups, participated. The overall recall rate (including secondary recalls) was lower for women in the blinded group than in the nonblinded group (blinded: 1140 of 53 291 women [2.1%], nonblinded: 1372 of 56 305 women [2.4%]; P = .001). There was no evidence of cancer detection rate differences between the groups (blinded: 349 of 53 291 women [6.5 per 1000 screening examinations], nonblinded: 360 of 56 305 women [6.4 per 1000 screening examinations]; P = .75). The blinded group thus had a higher positive predictive value of recall (blinded: 349 of 1140 women [30.6%], nonblinded: 360 of 1372 women [26.2%]; P = .02). Conclusion While interpreting screening mammograms for breast cancer, radiologists blinded to technologists' warning signals had lower recall rates with higher positive predictive values than nonblinded radiologists, yet cancer detection rates seemed to remain unchanged. See also the editorial by Hofvind and Lee in this issue. © RSNA, 2021.