Breast Density Changes the Breast-imaging Landscape

Cristen Bolan, MS


Appl Radiol. 2013;42(3):20-25. 

In This Article

Dense Breast Awareness

It is well established that mammographic breast density—a reflection of the proportions of fat, connective tissue, and epithelial tissue in the breast—is a risk factor for breast cancer. A recent study found women with dense tissue in 75% or more of the breast have a risk of breast cancer 4 to 6 times as great as the risk among women with little or no dense tissue.[1]

A study by doctors at Harvard Medical School and Brigham and Women's Hospital, Boston, MA, and colleagues, found higher mammographic density is associated with more aggressive tumor characteristics and also with in situ tumors.[2] The authors wrote: "masking of a tumor can occur because cancerous tissue and mammographically-dense tissue have similar x-ray attenuation, allowing tumors to go undetected on screening mammography examination and progress to a more advanced and aggressive stage before detection." They recommended "breast density should be included in risk prediction models across tumor subtypes."

These and other studies on mammography screening for women with dense breasts have catalyzed a movement for dense breast awareness. Earlier, growing concern over the efficacy of mammograms on women with dense breasts had prompted Connecticut to enact a law in 2009 requiring that women be informed of their breast density when they receive their mammography reports. Related legislation in the same state mandates that insurance companies provide coverage for comprehensive ultrasound screening of an entire breast or breasts if a mammogram demonstrates heterogeneous or dense breast tissue based on the Breast Imaging Reporting and Data System (BI-RADS) established by the American College of Radiology (ACR).[3] Since then, several others states have enacted similar breast- density notification laws.