Comparative Effectiveness of Digital Breast Tomosynthesis for Breast Cancer Screening Among Women 40-64 Years Old.

BACKGROUND: Digital breast tomosynthesis (DBT) may have a higher cancer detection rate and lower recall compared with 2-dimensional (2 D) mammography for breast cancer screening. The goal of this study was to evaluate screening outcomes with DBT in a real-world cohort and to characterize the population health impact of DBT as it is widely adopted. METHODS: This observational study evaluated breast cancer screening outcomes among women screened with 2 D mammography vs DBT. We used deidentified administrative data from a large private health insurer and included women aged 40-64 years screened between January 2015 and December 2017. Outcomes included recall, biopsy, and incident cancers detected. We used 2 complementary techniques: a patient-level analysis using multivariable logistic regression and an area-level analysis evaluating the relationship between population-level adoption of DBT use and outcomes. All statistical tests were 2-sided. RESULTS: Our sample included 7 602 869 mammograms in 4 580 698 women, 27.5% of whom received DBT. DBT was associated with modestly lower recall compared with 2 D mammography (113.6 recalls per 1000 screens, 99% confidence interval [CI] = 113.0 to 114.2 vs 115.4, 99% CI = 115.0 to 115.8, P < .001), although younger women aged 40-44 years had a larger reduction in recall (153 recalls per 1000 screens, 99% CI = 151 to 155 vs 164 recalls per 1000 screens, 99% CI = 163 to 166, P < .001). DBT was associated with higher biopsy rates than 2 D mammography (19.6 biopsies per 1000 screens, 99% CI = 19.3 to 19.8 vs 15.2, 99% CI = 15.1 to 15.4, P < .001) and a higher cancer detection rate (4.9 incident cancers per 1000 screens, 99% CI = 4.7 to 5.0 vs 3.8, 99% CI = 3.7 to 3.9, P < .001). Point estimates from the area-level analysis generally supported these findings. CONCLUSIONS: In a large population of privately insured women, DBT was associated with a slightly lower recall rate than 2 D mammography and a higher cancer detection rate. Whether this increased cancer detection improves clinical outcomes remains unknown.