A new study from the Breast Cancer Surveillance Consortium (BCSC) published in Cancer Epidemiology, Biomarkers & Prevention suggests that 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 prevalences and variability in breast cancer risk. In this study, led by University of California, Davis, Department of Public Health Sciences researcher Michael Bissell, PhD, we examined a subset of 3,786,802 observations from 1,071,653 women ages 35-84 years in the larger BCSC cohort and found that premenopausal breast density accounted for 23-35% of breast cancers and postmenopausal density accounted for 13-17% across races/ethnicities. We also found that if all overweight/obese postmenopausal women achieved a normal BMI, breast cancer incidence could be reduced by 12-15% in white, Asian, and Hispanic women and 28% in black women. These results suggest that primary and secondary prevention efforts targeting women who are overweight/obese or have dense breasts could have large benefits in reducing the burden of breast cancer in white, black, Asian, and Hispanic women, particularly among postmenopausal black women. Risk prediction models should consider interactions between these factors and race/ethnicity.

Full Text Citation and Link: Bissell MCS, Kerlikowske K, Sprague BL, Tice JA, Gard CC, Tossas KY, Rauscher GH, Trentham-Dietz A, Henderson LM, Onega T, Keegan THM, Miglioretti1 DL, on behalf of the Breast Cancer Surveillance Consortium. Breast Cancer Population Attributable Risk Proportions Associated with Body Mass Index and Breast Density by Race/Ethnicity and Menopausal Status [published online ahead of print, 2020 Jul 29]. Cancer Epidemiol Biomarkers Prev. 2020;cebp.0358.2020. doi:10.1158/1055-9965.EPI-20-0358. PMID: 32727722 [Link to Article]