Impact of Digital Breast Tomosynthesis on Extra Views and Concomitant Ultrasound Examinations in One Year Post Breast-Conserving Surgery Patients.

Introduction: Imaging surveillance of patients post breast surgery for breast cancer is routinely performed with mammography. In practice, a large number of patients receive a concomitant ultrasound. The latter has not been established as routine practice and varies across imaging departments and referrers. This study aims to determine if the use of digital breast tomosynthesis (DBT) has decreased the need for concomitant ultrasound and extra mammographic views compared to digital mammography (DM).

Methods: Data was retrospectively reviewed for patients undergoing surveillance mammography for two periods: 2015-2016 (DM) and 2018-2019 (DBT). Patients identified as first-year post breast-conserving surgery (BCS) were included in the study. Comparison of proportions of concomitant ultrasound use between the two periods, with subgroup analysis for breast density categories, was performed using Chi-squared tests.

Results: The study included 499 patients, of which 245 and 254 represented the DM and DBT periods, respectively, with a mean age of 60.1 years (SD 13.1) for the entire cohort. During DBT period, the percentage of patients having concomitant ultrasounds decreased by 15 percentage points (95% CI 8.9%-21.1%) (p < 0.0001) when compared to the DM period. During DBT period, the percentage of patients having extra views decreased by 44 percentage points (95% CI 36.1%-51.1%) (p < 0.0001).

Conclusion: The introduction of DBT resulted in fewer concomitant ultrasound examinations and extra mammographic views performed in the first-year post breast cancer treatment. The role of ultrasound in cancer surveillance post-treatment is debatable and large prospective studies investigating its value are warranted.