Multicenter Evaluation of Breast Cancer Screening with Digital Breast Tomosynthesis in Combination with Synthetic versus Digital Mammography

Abstract

BackgroundDigital breast tomosynthesis (DBT) combined with digital mammography (DM) is increasingly used in the United States instead of DM alone for breast cancer screening. Early screening outcomes incorporating synthetic mammography (SM) with DBT have suggested that SM is an acceptable non-radiation dose alternative to DM.PurposeTo compare multicenter outcomes from breast cancer screening with SM/DBT versus DM/DBT.Materials and MethodsThis was a retrospective study of consecutive screening mammograms obtained at two institutions. Eligible studies consisted of 34 106 DM/DBT examinations between October 3, 2011, and October 31, 2014, and 34 180 SM/DBT examinations between January 7, 2015, and February 2, 2018, at the University of Pennsylvania and 51 148 DM/DBT examinations between January 1, 2012, and May 31, 2016, and 31 929 SM/DBT examinations between June 1, 2016, and March 30, 2018, at the University of Vermont. Demographics of women who attended screening and results from screening were recorded. Recall rate, biopsy rate, false-negative rate, cancer detection rate, positive predictive value, sensitivity, and specificity were calculated according to modality and institution. Descriptive statistics, χ² tests, and logistic regression were used in analysis.ResultsThe study included 151 363 screening examinations among 151 363 women (mean age, 58.1 years ± 10.9 [standard deviation]). The unadjusted recall rate was lower with SM/DBT than with DM/DBT (7.0% [4630 of 66 109 examinations] for SM/DBT vs 7.9% [6742 of 85 254 examinations] for DM/DBT; P < .01). However, after multivariable adjustment, SM/DBT was associated with a slightly higher recall rate compared with DM/DBT (adjusted odds ratio [OR], 1.06; adjusted 95% CI: 1.01, 1.11; P = .02). Similarly, after multivariable adjustment, SM/DBT was associated with slightly lower specificity compared with DM/DBT (adjusted OR, 0.95; adjusted 95% CI: 0.90, 0.99; P = .02). There was no statistically significant difference in biopsy rate (P = .54), false-negative rate (P = .38), cancer detection rate (P = .55), invasive or in situ cancer detection rate (P = .52 and P = .98, respectively), positive predictive value (P = .78), or sensitivity (P = .33) for SM/DBT versus DM/DBT overall or within either institution (P > .05 for all).ConclusionBreast cancer screening performance is maintained within benchmarks when synthetic mammography replaces digital mammography in digital breast tomosynthesis imaging.© RSNA, 2020Online supplemental material is available for this article.See also the editorial by Lång in this issue.

Graphical abstract

Figure 1:

Example of artifactual pseudocalcifications on synthetic images in a 66-year-old woman who presented for screening. A, Screening mammogram obtained with synthetic imaging in 2019 (craniocaudal view). Finding was classified as Breast Imaging Reporting and Data System (BI-RADS) category 1. B, Screening mammogram obtained with synthetic imaging in 2020 (craniocaudal view). New calcifications in a linear distribution are seen in the outer breast. Finding was classified as BI-RADS category 0. Inset image was obtained at ×3 magnification. C, Diagnostic digital mammogram obtained in 2020 (craniocaudal view) reveals no calcifications in the outer breast. Previously seen calcification-like findings represent artifact from enhancement of ligaments or fibroglandular tissue on synthetic reconstruction. Finding was classified as BI-RADS category 1.

Figure 2:

Example of synthetic imaging calcification enhancement in a 43-year-old woman who presented for screening. A, Screening mammogram obtained with synthetic imaging (craniocaudal view). New faint amorphous calcifications are seen in the outer breast. Finding was classified as Breast Imaging Reporting and Data System (BI-RADS) category 0. Inset image was obtained at ×3 magnification. B, Diagnostic mammogram, two-dimensional magnification view (craniocaudal view), confirms the presence of calcifications; however, they are of equal or less conspicuity compared with that seen with synthetic imaging. Inset image was obtained at ×3 magnification. Finding was classified as BI-RADS category 4. C, Screening mammogram obtained with synthetic imaging (mediolateral oblique view). New faint amorphous calcifications are seen in the superior breast. They are less conspicuous compared with those on the craniocaudal view in A. Finding was classified as BI-RADS category 0. Inset image was obtained at ×3 magnification. D, Diagnostic digital mammogram obtained at recall (mediolateral view). Calcifications are much less conspicuous on two-dimensional digital mediolateral view. Inset image was obtained at ×3 magnification. Finding was classified as BI-RADS category 4. E, Diagnostic mammogram obtained with two-dimensional imaging after biopsy (digital mediolateral view). The clip is in appropriate location. Pathologic examination showed ductal carcinoma in situ, intermediate grade.