Which women benefit most from digital breast tomosynthesis?
NEW YORK 15/06 - Women with extremely dense breasts and at high risk of breast cancer may benefit the most from digital breast tomosynthesis (DBT), a new analysis suggests.
In this subgroup, compared with digital mammography, DBT was associated with a lower risk of advanced breast cancer, researchers found.
"Previous studies of digital mammography have shown that screening failures were highest among women with dense breasts and elevated breast cancer risk. DBT studies to date have not examined screening failures by breast density combined with breast cancer risk," Dr. Karla Kerlikowske of San Francisco Veterans Affairs Medical Center, in California, and colleagues note in JAMA.
They evaluated whether DBT screening is associated with a lower likelihood of interval invasive cancer and advanced breast cancer compared with digital mammography by extent of breast density and breast-cancer risk.
They analyzed data on more than 500,000 women who underwent roughly 1 million screening digital mammograms and 375,000 screening DBT exams from 2011 through 2018 at 44 U.S. Breast Cancer Surveillance Consortium (BCSC) facilities. Follow-up for cancer diagnosis lasted through 2019.
Interval invasive cancer rates were not significantly different for DBT versus digital mammography (0.57 vs. 0.61 per 1,000, respectively; P=0.43).
Among women with nondense breasts, heterogeneously dense breasts, or with extremely dense breasts but at low to average risk of breast cancer (96.4% of the study population), there were no significant differences in rates of advanced cancer (pathologic stage II or higher) between DBT and digital mammography.
However, among women with extremely dense breasts and a high risk of breast cancer (3.6% of the study population), advanced cancer rates were significantly lower for DBT than for digital mammography (0.27 vs. 0.80 per 1,000 exams over one year).
Dr. Sarah Friedewald of Northwestern University Feinberg School of Medicine in Chicago and Dr. Lars Grimm of Duke University in Durham, North Carolina, put the findings into perspective in a JAMA editorial.
"For the approximately 4% of women with elevated risk of breast cancer and with dense breasts undergoing routine mammography, the analysis by Kerlikowske et al supports preferentially performing screening with DBT," they write.
"For other women, evidence that the choice of digital mammography vs DBT influences mortality or interval cancers is lacking, although there is evidence that DBT is associated with lower recall rates," they point out.
"Given that DBT is now available at 83% of mammography facilities in the US and is not associated with higher burdens for women (unless there are higher co-pays), ensuring that women at high risk with dense breasts are screened with DBT should be feasible," the editorialists add.
The study had no commercial funding and the authors have no relevant disclosures.