Understanding Breast Density: What the New FDA Mammography Guidelines Mean for You

On September 10, the FDA set a requirement for mammography facilities to provide patients a density notification after a mammogram; either “not dense” or “dense.”

You may have seen news about this announcement. Fortunately, Florida has been providing density notifications since 2018. 

I think this is a great opportunity to review what exactly are “dense breasts?”

Breast density is related to the composition of the glandular milk producing breast elements to the fatty supportive tissue elements within the breast. Dense breasts have a greater proportion of the glandular tissue and this appears white on a mammogram. 

Breast density varies with factors such as age, BMI and genetics. Women’s breasts tend to get less dense with age-but, just like other age-related changes, such as wrinkles and grey hair- this change may happen at varying rates for each individual woman. 

The challenge with breast density is that it can make certain type of breast cancer difficult to see on mammograms. Masses in the breast can look white and can be obscured by the white dense tissue.  3D mammography can be helpful in women with dense breasts as it takes multiple images across the breast tissue, effectively resulting in little image slices. Other imaging modalities such as ultrasound and magnetic resonance imaging (MRI)  can also be effective in identifying cancers that be hard to see on mammogram.

Breast density is described in 4 lettered categories. A- predominately fatty, B – scattered fibroglandular, C- heterogeneously dense and D – extremely dense.   Categories A and B are considered “not dense,” whereas Category C and D are considered “dense.” These categories are usually mentioned at the start of a mammography report. 

If you have questions about the role of supplemental screening in dense breasts, ask your primary care provider, gynecologist or seek out a breast specialist.

Holy Cross Health only uses 3D mammography. We also offer ultrasound and abbreviated breast MRI for supplemental testing in dense breasts when appropriate. 

Learn more about women's imaging at Holy Cross Health.