A study on the prevalence of mammographically dense breasts in the United States “estimated that approximately 43% of women aged 40 to 74 years have heterogeneously or extremely dense breasts, corresponding to approximately 27.6 million U.S. women,” researchers reported in the Journal of the National Cancer Institute. Data from 1,518,599 mammograms conducted from 2007 through 2010 at mammography facilities in the Breast Cancer Surveillance Consortium (BCSC) were used to determine mammographic breast density distribution by age and body mass index, and these breast density distributions applied to age-specific and body mass index-specific counts of the female population taken from the 2010 U.S. Census and the National Health and Nutrition Examination Survey to estimate the number of American women with dense breasts.
The combined proportion of mammograms rated as heterogeneously or extremely dense was inversely associated with body mass index and age. Among women with a normal body mass index (18.5–24.9 kg/m2), 58.9% had heterogeneously or extremely dense breasts, compared with 25% of women with body mass index characterized as obese (> 30 kg/m2). The proportion of women with mammograms rated as either heterogeneous or extremely dense decreased from 56.6% for women aged 40 to 44 to 28.4% for women aged 85 or older. “In light of the ongoing controversies regarding mammography screening for women before age 50, it is notable that nearly 45% of women aged 40 to 74 years with dense breasts are younger than age 50 years,” the authors noted.
“Policymakers should consider the large prevalence of women with dense breasts when debating breast density notification legislation,” advised Brian L. Sprague, PhD, of the Office of Health Promotion Research at the University of Vermont in Burlington and colleagues. “Health-care providers need to carefully consider strategies to ensure that women who are notified have opportunities to discuss available evidence, evaluate breast cancer risk, and pursue supplemental screening options if deemed appropriate.” ■
Sprague BL, et al: J Natl Cancer Inst 106(10):dju255, 2014.