Digital breast tomosynthesis in the diagnostic settings of breast cancer patients treated by conservation therapy

Abstract

Abstract Background Breast cancer survivors who underwent breast conserving therapy (BCT) are still 10% more likely to develop a second breast cancer at follow-up, Digital mammography (DM) was advised in every practical guideline for follow-up after BCT; however, it was difficult to distinguish between actual recurrence and scar development at DM. Our research objective is to assess the value of Digital Breast Tomosynthesis (DBT) on the final Breast Imaging Reporting and Data System lexicon (BI-RADS) assessment categories compared to diagnostic digital mammography (DM) of breast cancer patients treated with breast conservation therapy (BCT), and to determine the additive value of DBT to DM or the use of DBT with synthetic 2D images in the diagnostic workup following BCT. Results Four hundred and seventeen breast cancer patients who underwent breast-conserving therapy (BCT) and received diagnostic assessments, including digital mammography (DM), digital breast tomosynthesis (DBT), and reconstructed synthetic 2D images, were enrolled in the study. There is a significant reduction in the proportion of studies classified as probably benign BI-RADS 3 in synthetic 2D + DBT and DM + DBT compared with those in DM alone, and this was demonstrated by the two readers and at double reading (all P = 0.01). There is a significant increase in the PPV of malignancy in synthetic 2D + DBT and DM + DBT compared with those in DM alone for reader 2 (P = 0.01) and at double reading (P < 0.04) without a significant difference in the proportion of studies classified as BI-RADS category 4 or 5 for both readers and at double reading (p > 0.3). Regarding the mammographic abnormalities, we noted a significant reduction in asymmetry and a significant increase in architectural distortion in synthetic 2D + DBT and DM + DBT compared with those in DM alone, and this was demonstrated by the two readers and at double reading (all P = 0.01). Conclusions The addition of digital breast tomosynthesis (DBT) into the diagnostic process after breast-conserving therapy (BCT), either in conjunction with digital mammography (DM) or with synthetic 2D images in the diagnostic workup following BCT, significantly decreases the proportion of studies classified as probably benign, significantly increases the rate of studies classified as normal or benign, and significantly increase in the positive predictive value (PPV) of malignancy without significant difference in the patients classified as BI-RADS category 4 or 5. Moreover it improved diagnostic confidence in biopsy recommendations, regardless of mammographic density.