Imaging Surveillance of Breast Cancer Survivors with Digital Mammography versus Digital Breast Tomosynthesis.

Background Among breast cancer survivors, detecting a breast cancer when it is asymptomatic (rather than symptomatic) improves survival; thus, imaging surveillance in these patients is warranted. Digital breast tomosynthesis (DBT) is used for screening, but data on DBT for surveillance in this high-risk population are limited. Purpose To determine whether DBT leads to improved screening performance metrics when compared with two-dimensional digital mammography among breast cancer survivors. Materials and Methods In this study, screening mammograms obtained in breast cancer survivors before and after DBT implementation were retrospectively reviewed (March 2008-February 2011 for the digital mammography group; January 2013-December 2017 for the DBT group). Mammograms were interpreted by breast imaging radiologists with the assistance of computer-aided detection. Performance metrics and tumor characteristics between the groups were compared using multivariable logistic regression models. Results The digital mammography and DBT groups were composed of 9019 and 22 887 mammographic examinations, respectively, in 8170 women (mean age, 62 years ± 12 [standard deviation]). In the DBT group, the abnormal interpretation rate was lower (5.8% [1331 of 22 887 examinations] vs 6.2% [563 of 9019 examinations]; odds ratio [OR], 0.80; 95% CI: 0.71, 0.91; = .001) and specificity was higher (95.0% [21 502 of 22 644 examinations] vs 94.7% [8424 of 8891 examinations]; OR, 1.23; 95% CI: 1.07, 1.41; = .003) than in the digital mammography group. The cancer detection rates did not differ (8.3 per 1000 examinations with DBT vs 10.6 with digital mammography; OR, 0.76; 95% CI: 0.57, 1.02; = .07). The proportions of screening-detected invasive cancers, versus in situ cancers, were similar (74% [140 of 189 cancers] in the DBT group vs 72% [69 of 96 cancers] in the digital mammography group; = .69). Of 86 interval cancers, 58% (50 of 86 cancers) manifested with symptoms, and 33% (28 of 86 cancers) were detected at screening MRI. Conclusion Among breast cancer survivors, screening with digital breast tomosynthesis led to fewer false-positive results and higher specificity but did not affect cancer detection. © RSNA, 2020 See also the editorial by Hooley and Butler in this issue.