DBT Bests Digital Mammography for cancer detection irrespective of breast density
Digital breast tomosynthesis (DBT) provides reconstructed, quasi-three-dimensional mammographic images of the breast, and has been proposed to improve cancer detection in screening through better visualisation of lesions that may be obscured by dense and/or overlapping breast tissue on conventional (two-dimensional) digital mammography (DM).
A recent study suggests that DBT has differential incremental cancer detection and recall by breast density than digital mammography (DM). The study findings were published in the British Journal of Cancer on 28 March 2022.
Multiple studies have compared DBT and DM in breast cancer screening, including six published systematic reviews. All of these reviews reported that detection measures favoured DBT (compared to DM) for breast cancer screening; however, none reported screening detection measures by high and low breast density. To address the knowledge gap Dr Tong Li and her team conducted a study to examine whether digital breast tomosynthesis detects differentially in high- or low-density screens.
In this systemic review, the researchers searched six databases (2009–2020) for studies comparing DBT and digital mammography and reporting cancer detection rate (CDR) and/or recall rate by breast density. They also performed a meta-analysis to assess pool incremental CDR and recall rate for DBT (versus DM) for high- and low-density (dichotomised based on BI-RADS) and within-study differences in incremental estimates between high- and low-density. Screening settings (European/US) were also compared.
Key findings of the study:
- Upon analysis, the researchers found that the pooled within-study difference in incremental CDR for high- versus low-density was 1.0/1000 screens.
- They noted that the estimates were not significantly different in US (0.6/1000) and European (1.9/1000) settings (p for subgroup difference = 0.15).
- For incremental recall rate, they observed that the within-study differences between density subgroups differed by setting.
- They noted that the pooled incremental recall was less in high- versus low-density screens (−0.9%) in US screening, and greater (0.8%) in European screening.
The authors concluded, "DBT has differential incremental cancer detection and recall by breast density. Although incremental CDR is greater in high-density, a substantial proportion of additional cancers is likely to be detected in low-density screens. Our findings may assist screening programmes considering DBT for density-tailored screening."
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