Key Points Question Is there a difference between screening with digital breast tomosynthesis vs digital mammography in the probability of false-positive results after 10 years of screening? Findings In this comparative effectiveness study of 903 495 individuals undergoing 2 969 055 screening examinations, the 10-year cumulative probability of receiving at least 1 false-positive recall was 6.7% lower for tomosynthesis vs digital mammography with annual screening and 2.4% lower for tomosynthesis vs digital mammography with biennial screening, a significant difference. Meaning The findings of this study suggest that digital breast tomosynthesis is associated with a lower cumulative probability of false-positive results compared with digital mammography; biennial vs annual screening was associated with larger reductions in cumulative false-positive risk for both modalities.

declares that he has no conflict of interest. Michael C. S. Bissell declares that he has no conflict of interest. Diana L. Miglioretti, PhD declares that she has no conflict of interest. Charlotte C. Gard, PhD, MBA declares that she has no conflict of interest. Garth H. Rauscher, PhD declares that he has no conflict of interest. Firas M. Dabbous, MS, PhD declares that he has no conflict of interest. Karla Kerlikowske, MD declares that she has no conflict of interest.Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Each registry and the Statistical Coordinating Center received institutional review board approval and a Federal Certificate of Confidentiality and other protection for the identities of the research subjects. All procedures are Health Insurance Portability and Accountability Act (HIPAA) compliant.

Background: Overweight/obesity and dense breasts are strong breast cancer risk factors whose prevalences vary by race/ethnicity. The breast cancer population attributable risk proportions (PARP) explained by these factors across racial/ethnic groups are unknown.Methods: We analyzed data collected from 3,786,802 mammography examinations (1,071,653 women) in the Breast Cancer Surveillance Consortium, associated with 21,253 invasive breast cancers during a median of 5.2 years follow-up. HRs for body mass index (BMI) and breast density, adjusted for age and registry were estimated using separate Cox regression models by race/ethnicity (White, Black, Hispanic, Asian) and menopausal status. HRs were combined with observed risk-factor proportions to calculate PARPs for shifting overweight/obese to normal BMI and shifting heterogeneously/extremely dense to scattered fibroglandular densities.Results: The prevalences and HRs for overweight/obesity and heterogeneously/extremely dense breasts varied across races/ ethnicities and menopausal status. BMI PARPs were larger for postmenopausal versus premenopausal women (12.0%-28.3% vs. 1.0%-9.9%) and nearly double among postmenopausal Black women (28.3%) than other races/ethnicities (12.0%-15.4%). Breast density PARPs were larger for premenopausal versus postmenopausal women (23.9%-35.0% vs. 13.0%-16.7%) and lower among premenopausal Black women (23.9%) than other races/ethnicities (30.4%-35.0%). Postmenopausal density PARPs were similar across races/ethnicities (13.0%-16.7%).Conclusions: Overweight/obesity and dense breasts account for large proportions of breast cancers in White, Black, Hispanic, and Asian women despite large differences in risk-factor distributions.Impact: Risk prediction models should consider how race/ethnicity interacts with BMI and breast density. Efforts to reduce BMI could have a large impact on breast cancer risk reduction, particularly among postmenopausal Black women.

Background The utility of incorporating detailed family history into breast cancer risk prediction hinges on its independent contribution to breast cancer risk. We evaluated associations between detailed family history and breast cancer risk while accounting for breast density. Methods We followed 222,019 participants aged 35–74 in the Breast Cancer Surveillance Consortium, of whom 2,456 developed invasive breast cancer. We calculated standardized breast cancer risks within joint strata of breast density and simple (1st-degree female relative) or detailed (1st-degree, 2nd-degree, or 1st- and 2nd-degree female relative) breast cancer family history. We fit log-binomial models to estimate age-specific breast cancer associations for simple and detailed family history, accounting for breast density. Results Simple 1st-degree family history was associated with increased breast cancer risk compared with no 1st-degree history (RR=1.5, 95%CI 1.0–2.1 at age 40; RR=1.5, 95%CI 1.3–1.7 at age 50; RR=1.4, 95%CI 1.2–1.6 at age 60; RR=1.3, 95%CI 1.1–1.5 at age 70). Breast cancer associations with detailed family history were strongest for women with 1st- and 2nd-degree family history compared with no history (RR=1.9, 95%CI 1.1–3.2 at age 40); this association weakened in higher age groups (RR=1.2, 95%CI 0.88–1.5 at age 70). Associations did not change substantially when adjusted for breast density. Conclusion Even with adjustment for breast density, a history of breast cancer in both 1st- and 2nd-degree relatives is more strongly associated with breast cancer than simple 1st-degree family history. Impact Future efforts to improve breast cancer risk prediction models should evaluate detailed family history as a risk factor.

ImportanceDiagnostic delays in breast cancer detection may be associated with later-stage disease and higher anxiety, but data on multilevel factors associated with diagnostic delay are limited.ObjectiveTo evaluate individual-, neighborhood-, and health care–level factors associated with differences in time from abnormal screening to biopsy among racial and ethnic groups.Design, Setting, and ParticipantsThis prospective cohort study used data from women aged 40 to 79 years who had abnormal results in screening mammograms conducted in 109 imaging facilities across 6 US states between 2009 and 2019. Data were analyzed from February 21 to November 4, 2021.ExposuresIndividual-level factors included self-reported race and ethnicity, age, family history of breast cancer, breast density, previous breast biopsy, and time since last mammogram; neighborhood-level factors included geocoded education and income based on residential zip codes and rurality; and health care–level factors included mammogram modality, screening facility academic affiliation, and facility onsite biopsy service availability. Data were also assessed by examination year.Main Outcome and MeasuresThe main outcome was unadjusted and adjusted relative risk (RR) of no biopsy within 30, 60, and 90 days using sequential log-binomial regression models. A secondary outcome was unadjusted and adjusted median time to biopsy using accelerated failure time models.ResultsA total of 45 186 women (median [IQR] age at screening, 56 [48-65] years) with 46 185 screening mammograms with abnormal results were included. Of screening mammograms with abnormal results recommended for biopsy, 15 969 (34.6%) were not resolved within 30 days, 7493 (16.2%) were not resolved within 60 days, and 5634 (12.2%) were not resolved within 90 days. Compared with White women, there was increased risk of no biopsy within 30 and 60 days for Asian (30 days: RR, 1.66; 95% CI, 1.31-2.10; 60 days: RR, 1.58; 95% CI, 1.15-2.18), Black (30 days: RR, 1.52; 95% CI, 1.30-1.78; 60 days: 1.39; 95% CI, 1.22-1.60), and Hispanic (30 days: RR, 1.50; 95% CI, 1.24-1.81; 60 days: 1.38; 95% CI, 1.11-1.71) women; however, the unadjusted risk of no biopsy within 90 days only persisted significantly for Black women (RR, 1.28; 95% CI, 1.11-1.47). Sequential adjustment for selected individual-, neighborhood-, and health care–level factors, exclusive of screening facility, did not substantially change the risk of no biopsy within 90 days for Black women (RR, 1.27; 95% CI, 1.12-1.44). After additionally adjusting for screening facility, the increased risk for Black women persisted but showed a modest decrease (RR, 1.20; 95% CI, 1.08-1.34).Conclusions and RelevanceIn this cohort study involving a diverse cohort of US women recommended for biopsy after abnormal results on screening mammography, Black women were the most likely to experience delays to diagnostic resolution after adjusting for multilevel factors. These results suggest that adjustment for multilevel factors did not entirely account for differences in time to breast biopsy, but unmeasured factors, such as systemic racism and other health care system factors, may impact timely diagnosis.