Abstract 3768: Comparison of breast density measured by dual energy x-ray Absorptiometry (DXA) with mammographic density among adult women

Abstract

Abstract Mammographic density, the distribution of fat, connective, and epithelial tissues in the female breast, is strongly associated with breast cancer and has been used as a biomarker for breast cancer risk among adult women. While use of mammography is limited due to concerns about radiation exposure, Dual Energy X-ray Absorptiometry (DXA), commonly available in medical care settings, has very low radiation. In this analysis, we compared breast density measured by DXA with mammographic density among adult women. We recruited 101 participants aged 30 years and older with a normal mammogram (defined as BIRADS categories 1 through 3) through Kaiser Permanente Hawaii. After completing a questionnaire asking for demographic, reproductive, anthropometric, and medical information, all women received DXA scans of both breasts, as well as of the whole body, using a GE Lunar Prodigy Bone Densitometer. On the DXA scans, the breast image was manually outlined and the following measures were computed: percent fibroglandular volume density (% FGV), absolute fibroglandular volume, total breast area, and volume. After digitizing the most recent craniocaudal (CC) and mediolateral (ML) mammograms, total breast area, dense area, and percent density were estimated using a computer-assisted method (Cumulus). For the overall population, mean % FGV was 38.8±14.3%, and mean percent density was 31.9±18.2% for CC views and 28.3±16.2% for ML views. Both DXA and mammographic measures showed high correlations between left and right breasts ranging from 0.85 to 0.98 (p <0.0001). When comparing DXA and mammographic measures, the correlation coefficients between % FGV and percent density were 0.76 for both CC and ML views (p <0.0001). Associations with common risk factors showed similar patterns for DXA and mammographic densities; in particular, the inverse associations with BMI and age at menarche were evident for both methods. Multilinear regression with stepwise selection indicated an explained variance of 0.57 for % FGV alone and 0.58 for % FGV plus parity. The current comparison suggests that DXA has the potential to provide a low-radiation option to evaluate breast density for women who do not undergo mammography. This may allow improved individualized risk assessment to identify women for targeted prevention strategies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3768.