Purpose Digital breast tomosynthesis (DBT) is emerging as the new standard of care for breast cancer screening based on improved cancer detection coupled with reductions in recall compared to screening with digital mammography (DM) alone. However, many prior studies lack follow-up data to assess false negatives examinations. The purpose of this study is to assess if DBT is associated with improved screening outcomes based on follow-up data from tumor registries or pathology. Methods Retrospective analysis of prospective cohort data from three research centers performing DBT screening in the PROSPR consortium from 2011–2014 was performed. Recall and biopsy rates were assessed from 198,881 women age 40–74 years undergoing screening (142,883 DM and 55,998 DBT examinations). Cancer, cancer detection, and false negative rates and positive predictive values were assessed on examinations with one year of follow-up. Logistic regression was used to compare DBT to DM adjusting for research center, age, prior breast imaging, and breast density. Results There was a reduction in recall with DBT compared to DM (8.7% vs. 10.4%, p<0.0001), with adjusted OR=0.68 (95% CI=0.65–0.71). DBT demonstrated a statistically significant increase in cancer detection over DM (5.9 vs. 4.4/1,000 screened, adjusted OR=1.45, 95% CI=1.12–1.88), an improvement in PPV1 (6.4% for DBT vs. 4.1% for DM, adjusted OR=2.02, 95% CI=1.54–2.65), and no significant difference in false negative rates for DBT compared to DM (0.46 vs. 0.60/1,000 screened, p=0.347). Conclusions Our data support implementation of DBT screening based on increased cancer detection, reduced recall, and no difference in false negative screening examinations.

IMPORTANCE Breast cancer screening examinations using digital breast tomosynthesis (DBT) has been shown to be associated with decreased false-positive test results and increased breast cancer detection compared with digital mammography (DM). Little is known regarding the size and stage of breast cancer types detected and their association with age and breast density. OBJECTIVE To determine whether screening examinations using DBT detect breast cancers that are associated with an improved prognosis and to compare the detection rates by patient age and breast density. DESIGN, SETTING, AND PARTICIPANTS This retrospective analysis of prospective cohort data from 3 research centers in the Population-based Research Optimizing Screening Through Personalized Regimens (PROSPR) consortium included data of women aged 40 to 74 years who underwent screening examinations using

Background The coronavirus disease 2019 (COVID-19) pandemic led to a near-total cessation of mammography services in the United States in mid-March 2020. It is unclear if screening and diagnostic mammography volumes have recovered to pre-pandemic levels and whether utilization has varied by women’s characteristics. Methods We collected data on 461,083 screening mammograms and 112,207 diagnostic mammograms conducted during January 2019 through July 2020 at 62 radiology facilities in the Breast Cancer Surveillance Consortium. We compared monthly screening and diagnostic mammography volumes before and during the pandemic, stratified by age, race/ethnicity, breast density, and family history of breast cancer. Results Screening and diagnostic mammography volumes in April 2020 were 1.1% (95% confidence interval [CI] = 0.5% to 2.4%) and 21.4% (95% CI = 18.7% to 24.4%) of April 2019 pre-pandemic volumes, respectively, but by July 2020 rebounded to 89.7% (95% CI = 79.6% to 101.1%) and 101.6% (95% CI = 93.8% to 110.1%) of July 2019 pre-pandemic volumes, respectively. The year-to-date cumulative volume of screening and diagnostic mammograms performed through July 2020 was 66.2% (95% CI = 60.3% to 72.6%) and 79.9% (95% CI = 75.4% to 84.6%), respectively, of year-to-date volume through July 2019. Screening mammography rebound was similar across age groups and by family history of breast cancer. Monthly screening mammography volume in July 2020 for Black, White, Hispanic, and Asian women reached 96.7% (95% CI = 88.1% to 106.1%), 92.9% (95% CI = 82.9% to 104.0%), 72.7% (95% CI = 56.5% to 93.6%), and 51.3% (95% CI = 39.7% to 66.2%) of July 2019 pre-pandemic volume, respectively. Conclusion Despite a strong overall rebound in mammography volume by July 2020, the rebound lagged among Asian and Hispanic women and a substantial cumulative deficit in missed mammograms accumulated, which may have important health consequences.

Background About half of US states currently require radiology facilities to disclose mammographic breast density to women, often with language recommending discussion of supplemental screening options for women with dense breasts. Objective To examine variation in breast density assessment across radiologists in clinical practice. Design Cross-sectional and longitudinal analyses of prospectively collected observational data. Setting Thirty radiology facilities within the three breast cancer screening research centers of the Population-based Research Optimizing Screening through Personalized Regimens (PROSPR) consortium. Participants Radiologists who interpreted ≥500 screening mammograms during 2011–2013 (N=83). Data on 216,783 screening mammograms from 145,123 woman aged 40–89 years were included. Measurements Mammographic breast density as clinically recorded using the four Breast Imaging-Reporting and Data System density categories (heterogeneously dense and extremely dense categories were considered “dense” for analyses); patient age, race, and body mass index (BMI). Results Overall, 36.9% of mammograms were rated as dense. Across radiologists, this percentage ranged from 6.3% to 84.5% (median 38.7%, interquartile range 22.0%), with multivariable adjustment for patient characteristics having little impact (interquartile range 20.9%). Examination of patient subgroups revealed that variation in density assessment across radiologists was pervasive in all but the most extreme patient age and BMI combinations. Among women undergoing consecutive exams interpreted by different radiologists, 17.2% (5,909/34,271) had discordant assessments of dense/non-dense status. Limitations Quantitative measures of mammographic breast density were not available for comparison. Conclusions There is wide variation in density assessment across radiologists that should be carefully considered by providers and policy makers when considering supplemental screening strategies. The likelihood of a woman being told she has dense breasts varies substantially according to which radiologist interprets her mammogram. Funding Source National Institutes of Health

Elevated mammographic density (MD) is an established breast cancer risk factor. Reduced involution of terminal duct lobular units (TDLUs), the histologic source of most breast cancers, has been associated with higher MD and breast cancer risk. We investigated relationships of TDLU involution with area and volumetric MD, measured throughout the breast and surrounding biopsy targets (peri-lesional). Three measures inversely related to TDLU involution (TDLU count/mm2, median TDLU span, median acini count/TDLU) assessed in benign diagnostic biopsies from 348 women, ages 40–65, were related to MD area (quantified with thresholding software) and volume (assessed with a density phantom) by analysis of covariance, stratified by menopausal status and adjusted for confounders. Among premenopausal women, TDLU count was directly associated with percent peri-lesional MD (P-trend=0.03), but not with absolute dense area/volume. Greater TDLU span was associated with elevated percent dense area/volume (P-trend<0.05) and absolute peri-lesional MD (P=0.003). Acini count was directly associated with absolute peri-lesional MD (P=0.02). Greater TDLU involution (all metrics) was associated with increased nondense area/volume (P-trend≤0.04). Among postmenopausal women, TDLU measures were not significantly associated with MD. Among premenopausal women, reduced TDLU involution was associated with higher area and volumetric MD, particularly in peri-lesional parenchyma. Data indicating that TDLU involution and MD are correlated markers of breast cancer risk suggest that associations of MD with breast cancer may partly reflect amounts of at-risk epithelium. If confirmed, these results could suggest a prevention paradigm based on enhancing TDLU involution and monitoring efficacy by assessing MD reduction.