Researchers from the University of Genoa in Italy have just published an article in the Journal of Clinical Oncology that could have important implications for breast screening. Known as Adjunct Screening with Tomosynthesis or Ultrasound in Women with Mammography-Negative Dense Breasts – ASTOUND – the trial was designed to answer a simple question. When women with dense breast tissue have a negative mammogram and are followed up with adjunctive imaging, what modality is more successful in detecting breast cancer: tomosynthesis or ultrasound?
Alberto Tagliafico (above right) and colleagues conducted a prospective multi-centre study of asymptomatic women who, when screened with full-field digital mammography (FFDM), were judged to have heterogeneously or extremely dense breasts (BI-RADS 3 or 4) and their two-dimensional FFDM images were diagnosed as negative. A total of 3,231 women consented to participate in the trial. Each subject underwent examinations with digital breast tomosynthesis (DBT), using the Hologic Selenia Dimensions system, and hand-held ultrasound by an experienced radiologist who was blinded to the DBT results but was aware that the 2D FFDM results were negative.
The outcome measures included cancer detection rate plus the number of false-positive recalls. Among the 3,231 participants, 24 breast cancers were diagnosed, of which 23 were invasive. DBT detected 13 of the cancers (a rate of 3.0 per 1,000 women screened), while hand-held ultrasound detected 23 cancers (a rate of 7.1 per 1,000). DBT and ultrasound each generated 107 false-positive recalls (a rate of 3.3%) that led to biopsy, with no significant difference between the two modalities.
Nehmat Houssami, one of the co-authors who has just presented the findings at the European Breast Cancer Conference held in Amsterdam, commented “If adjunct ultrasound is not routinely performed in mammography-negative dense breasts, then our results could be taken to support the use of adjunct tomosynthesis, despite its lower incremental cancer detection rate relative to ultrasound.” However, in an editorial that accompanied the paper by Tagliafico et al., Wendie Berg (seen at left) was not convinced: “On the basis of the results from ASTOUND, tomosynthesis still misses a substantial number of invasive cancers in women with dense breasts.” She therefore advocated the use of ultrasound when it was available.
As we highlighted in last week’s blog, CapeRay’s Aceso system has successfully integrated FFDM and automated breast ultrasound (ABUS) and requires just 10 minutes to acquire both sets of images. Given the benefits of DBT vs FFDM, perhaps the ultimate screening device in future would combine DBT and ABUS in a single platform.