National Performance Benchmarks for Modern Screening Digital Mammography: Update from the Breast Cancer Surveillance Consortium

Abstract

Purpose To establish performance benchmarks for modern screening digital mammography and assess performance trends over time in U.S. community practice. Materials and Methods This HIPAA-compliant, institutional review board-approved study measured the performance of digital screening mammography interpreted by 359 radiologists across 95 facilities in six Breast Cancer Surveillance Consortium (BCSC) registries. The study included 1 682 504 digital screening mammograms performed between 2007 and 2013 in 792 808 women. Performance measures were calculated according to the American College of Radiology Breast Imaging Reporting and Data System, 5th edition, and were compared with published benchmarks by the BCSC, the National Mammography Database, and performance recommendations by expert opinion. Benchmarks were derived from the distribution of performance metrics across radiologists and were presented as 50th (median), 10th, 25th, 75th, and 90th percentiles, with graphic presentations using smoothed curves. Results Mean screening performance measures were as follows: abnormal interpretation rate (AIR), 11.6 (95% confidence interval [CI]: 11.5, 11.6); cancers detected per 1000 screens, or cancer detection rate (CDR), 5.1 (95% CI: 5.0, 5.2); sensitivity, 86.9% (95% CI: 86.3%, 87.6%); specificity, 88.9% (95% CI: 88.8%, 88.9%); false-negative rate per 1000 screens, 0.8 (95% CI: 0.7, 0.8); positive predictive value (PPV) 1, 4.4% (95% CI: 4.3%, 4.5%); PPV2, 25.6% (95% CI: 25.1%, 26.1%); PPV3, 28.6% (95% CI: 28.0%, 29.3%); cancers stage 0 or 1, 76.9%; minimal cancers, 57.7%; and node-negative invasive cancers, 79.4%. Recommended CDRs were achieved by 92.1% of radiologists in community practice, and 97.1% achieved recommended ranges for sensitivity. Only 59.0% of radiologists achieved recommended AIRs, and only 63.0% achieved recommended levels of specificity. Conclusion The majority of radiologists in the BCSC surpass cancer detection recommendations for screening mammography; however, AIRs continue to be higher than the recommended rate for almost half of radiologists interpreting screening mammograms. ^© RSNA, 2016 Online supplemental material is available for this article.

Figure 1:

Graphs show common performance measures. Sensitivity was restricted to final readers with 30 or more cancers (n = 104). Specificity was restricted to final readers with 1000 or more noncancers (n = 249). CDR was restricted to final readers with 1000 or more examinations (n = 242). Recall rate was restricted to final readers with 1000 or more examinations (n = 242). Max = maximum, min = minimum, p10 = 10th percentile, p25 = 25th percentile, p75 = 75th percentile, p90 = 90th percentile.

Figure 2:

Graph shows FNR, which was restricted to final readers with 3000 or more examinations (n = 194). Max = maximum, min = minimum, p10 = 10th percentile, p25 = 25th percentile, p75 = 75th percentile, p90 = 90th percentile.

Figure 3:

Graph shows PPVs. PPV1 was restricted to final readers with 100 or more abnormal examinations (n = 255). PPV2 was restricted to final readers with 30 or more recommended biopsies (n = 172). PPV3 was restricted to final readers with 30 or more biopsies performed (n = 125). Max = maximum, min = minimum, p10 = 10th percentile, p25 = 25th percentile, p75 = 75th percentile, p90 = 90th percentile.

Figure 4:

Graphs show cancer characteristics. Percentage minimal cancer was restricted to final readers with 15 or more detected cancers (n = 140) of known size. Percentage of cancers that were node negative was restricted to final readers with 15 or more detected invasive cancers (n = 111) of known size. Percentage of cancers that were stage 0 or 1 was restricted to final readers with 15 or more detected cancers (n = 143) of known stage. Max = maximum, min = minimum, p10 = 10th percentile, p25 = 25th percentile, p75 = 75th percentile, p90 = 90th percentile.

Figure 5:

Graph shows results for mean invasive cancer size. Mean size was restricted to final readers with 15 or more detected invasive cancers (n = 111) of known size. Max = maximum, min = minimum, p10 = 10th percentile, p25 = 25th percentile, p75 = 75th percentile, p90 = 90th percentile.