More Than 40% of U.S. Women Have Mammographically Dense Breasts
In a study reported in the Journal of the National Cancer Institute, Sprague et al found that more than 40% of U.S. women have mammographically dense breasts, with the prevalence being inversely proportional to age and body mass index (BMI). As noted by the authors: “National legislation is under consideration that would require women with mammographically dense breasts to be informed of their breast density and encouraged to discuss supplemental breast cancer screening with their health care providers.”
Prevalence
The study involved data from 1,518,599 mammograms conducted between 2007 and 2010 at mammography facilities in the Breast Cancer Surveillance Consortium. Overall, 43.3% (95% confidence interval [CI] = 43.1%–43.4%) of women aged 40 to 74 years had heterogeneously or extremely dense breasts.
According to age group, the proportions of women with heterogeneously or extremely dense breasts were 57% in the 40- to 44-year group, 55% in the 45- to 49-year group, 46% in the 50- to 54-year group, 38% in the 55- to 59-year group, 33% in the 60- to 64-year group, 31% in the 65- to 69-year group, 26% in the 70- to 74-year group, 28% in the 75- to 79-year group, 28% in the 80- to 84-year group, and 28 in the ≥ 85 year group.
According to BMI, the proportions were 76%, 59%, 40%, and 25% for BMI of < 18.5, 18.5 to < 25, 25 to < 30, and ≥ 30 kg/m2, respectively.
27.6 Million Women
Based on the age and BMI distribution of U.S. women, it was estimated that 27.6 million women (95% CI = 27.5–27.7 million) aged 40 to 74 years have heterogeneously or extremely dense breasts. Women aged 40 to 49 years (n = 12.3 million) account for 44.3% of this population.
The investigators concluded: “The prevalence of dense breasts among US women of common breast cancer screening ages exceeds 25 million. Policymakers and healthcare providers should consider this large prevalence when debating breast density notification legislation and designing strategies to ensure that women who are notified have opportunities to evaluate breast cancer risk and discuss and pursue supplemental screening options if deemed appropriate.”
Brian L. Sprague, PhD, of the University of Vermont, Burlington, is the corresponding author for the Journal of the National Cancer Institute article.
The study was supported by the National Cancer Institute–funded Breast Cancer Surveillance Consortium, National Cancer Institute, and Department of Biostatistics and Medical Informatics at the University of Wisconsin.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
