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; P =.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; P =.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; P =.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; P =.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. (C) RSNA, 2020

Automated summary

Among breast cancer survivors, screening with digital breast tomosynthesis (DBT) resulted in fewer false-positive results and higher specificity compared to digital mammography, but did not impact cancer detection rates.