Abstract A119: Comparing the variability of two validated, quantitative breast density measures used in a community-based mammography registry across race and ethnicity
Authors: Taffe Brianna D. , Henderson Louise , Kuzmiak Cherie , Kontos Despina , Nyante Sarah 
Published: January 2023

Abstract
Background: Breast density, an independent predictor of breast cancer risk, can be measured in multiple ways. Area-based measures quantify breast tissue in a 2-dimensional (2D) space, whereas volumetric, 3-dimensional (3D) measures incorporate information on the spatial relationship of dense and non-dense tissues that is not captured by 2D measures. Prior studies have shown that both types of measures vary by race/ethnicity. We compared the consistency of the relationship between validated 2D and 3D breast density measures across racial and ethnic groups. Methods: This study used data from 920 women aged 18+ who received a full-field digital screening mammogram at one of 6 breast imaging facilities in central North Carolina between 2017-2018. Race and ethnicity were abstracted from electronic medical records. Quantitative breast density was measured from mammograms and included (1) Area-based density measured using the Laboratory for Individualized Breast Radiodensity Assessment (LIBRA), an algorithm-based software package that produces 2D estimates of the amount of dense breast tissue and total breast area; and (2) Volumetric density measured using Volpara, which produces 3D estimates of breast fibroglandular tissue volume and total breast volume. Percent density was calculated as the ratio of dense or fibroglandular tissue to total breast area or volume. Spearman correlation coefficients (R) and 95% confidence intervals (CI) were used to quantify associations between 2D and 3D measures. Results: Participants were 33-86 years old (mean=57.9, SD=11.2) and identified as White (73%), Black (19%), Asian (3%), and Other race (6%). 5% identified as Hispanic. Percent density measures were highly correlated, with strong correlations across racial groups (White: R=0.88, 95% CI: 0.86, 0.90; Black: R=0.81, 95% CI: 0.75, 0.85; Asian: R=0.91, 95% CI: 0.81, 0.96; Other: R=0.86, 95% CI: 0.77, 0.92), and ethnic groups (Hispanic: R=0.82, 95% CI: 0.71, 0.90; non-Hispanic: R=0.88, 95% CI: 0.87, 0.90). Correlations between dense area and fibroglandular volume were lower, but were also consistent across racial groups (White: R=0.41, 95% CI: 0.35, 0.47; Black: R=0.42, 95% CI: 0.29, 0.54; Asian: R=0.33, 95% CI: -0.07, 0.64; Other: R=0.55, 95% CI: 0.32, 0.72). The correlation between dense area and fibroglandular volume was slightly stronger among Hispanic vs. non-Hispanic women (R=0.62, 95% CI: 0.41, 0.76 vs. R=0.39, 95% CI: 0.33, 0.44), although confidence intervals for the two estimates overlapped suggesting the difference was not statistically significant. Conclusions: Correlations between 2D and 3D percent density measures were consistent across racial and ethnic groups. These data suggest that use of 2D vs. 3D estimation tools is unlikely to contribute to between-study heterogeneity in racial/ethnic differences for studies of breast density in diverse populations. Generalizability for Asian and Hispanic women may be limited by the low prevalence of these groups in our sample. Studies with greater representation are needed for precise estimates in these groups.
Citation Format: Brianna D. Taffe, Louise Henderson, Cherie Kuzmiak, Despina Kontos, Sarah Nyante. Comparing the variability of two validated, quantitative breast density measures used in a community-based mammography registry across race and ethnicity [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr A119.