Implications and next steps
Dr. Lowry and colleagues noted that use of DBT has increased steadily since it was approved by the Food and Drug Administration in 2011, driven by studies demonstrating, among other things, earlier detection of invasive cancers.
The problem has been that previous investigations “largely dichotomized dense (heterogeneously dense and extremely dense) and nondense (almost entirely fat and scattered fibroglandular densities) categories,” the authors wrote. Therefore, the nuance of benefit across density subtypes hasn’t been clear.
The finding that “screening benefits of DBT differ for women with heterogeneously dense breasts [versus] extremely dense breasts is especially important in the current landscape of density legislation and demand for supplemental screening tests beyond mammography. To date, most state mandates and ... proposed federal legislation have uniformly grouped women with heterogeneously dense breasts and those with extremely dense breasts as a single population,” the authors wrote.
As the new findings suggest, “there are important differences in performance that may not be appreciated by combining density categories,” the authors added.
The results “suggest that women with extremely dense breast tissue may benefit more from additional screening than women with heterogeneously dense breasts who undergo tomosynthesis mammography,” Catherine Tuite, MD, of Fox Chase Cancer Center in Philadelphia, and colleagues wrote in a related editorial.
“Research to determine density and risk-specific outcomes for supplemental screening methods, such as magnetic resonance imaging ... molecular breast imaging, or ultrasonography is necessary to understand which screening method beyond DBT is best for average-risk women with heterogeneous or extremely dense breasts,” the editorialists wrote.
This research was funded by the National Cancer Institute and the Patient-Centered Outcomes Research Institute through the Breast Cancer Surveillance Consortium. Dr. Lowry reported grants from GE Healthcare outside the submitted work. The editorialists didn’t have any disclosures.
SOURCE: Lowry K et al. JAMA Netw Open. 2020 Jul 1;3(7):e2011792.