Women undergoing baseline screening may benefit most from digital breast tomosynthesis (DBT), but the benefits may vary by age and density category on subsequent screens, according to an analysis published in JAMA Network Open (2020;3(7):e2011792. doi:10.1001/jamanetworkopen.2020.11792).
Kathryn P. Lowry, MD, Department of Radiology, University of Washington, Seattle Cancer Care Alliance, and colleagues conducted this comparative effectiveness study evaluating digital mammography (DM) versus DBT performance by age, baseline vs subsequent screening round, and breast density category in the community practice setting.
Screening examinations between January 2010 and April 2018 of women between 40 and 79 years of age with history of breast cancer, mastectomy, or breast augmentation at 46 participating Breast Cancer Surveillance Consortium facilities were included in the analysis. A total of 1,584,079 DM (n = 1,273,492) and DBT (n = 310,587) screening examinations were analyzed.
The main outcome measures were absolute rates and relative risks (RR) of screening recall and cancer detection.
Adjusted differences in DM versus DBT performance were the largest on baseline examinations. Per 1000 baseline examinations in women ages 50-59, recall rates decreased from 241 examination for DM to 204 examination for DBT (RR, 0.84; 95% CI, 0.73-0.98), and cancer detection rates increased from 5.9 with DM to 8.8 with DBT (RR, 1.50; 95% CI, 1.10-2.08).
On subsequent examinations, women aged 40 to 79 years with heterogeneously dense breasts had improved recall rates and improved cancer detection with DBT. Per 1000 examinations in women aged 50 to 59 years, the number of recall examinations decreased from 102 with DM to 93 with DBT (RR, 0.91; 95% CI, 0.84-0.98), and cancer detection increased from 3.7 with DM to 5.3 with DBT (RR, 1.42; 95% CI, 1.23-1.64).
When looking at screening performance by breast density, women aged 50 to 79 years with scattered fibroglandular density had improved recall and cancer detection rates with DBT. Women aged 40 to 49 years with scattered fibroglandular density and women aged 50 to 79 years with almost entirely fatty breasts benefited from improved recall rates without change in cancer detection rates.
No improvements in recall or cancer detection rates were observed in women with extremely dense breast on subsequent examination for any age group.
“Our results suggest that the largest performance improvements with DBT compared with DM may occur in women undergoing baseline screening mammography,” concluded Dr Lowry and colleagues.
“Our results provide guidance for women and physicians making decisions regarding use of DBT for routine screening,” they added.—Janelle Bradley
