What are Dense Breasts



Breasts are made up of Fibrous Tissue, Glandular Tissue and Fatty Tissue. During a mammography screening a radiologist will be able to determine if your tissue is mostly made up of:

1) fat (about 10% of women)

2) scattered dense tissue throughout the breast (about 40% of women)


3) evenly dense tissue throughout the breast (about 40% of women), or


4) extremely dense tissue which makes up the remaining 10%.

A first important note: Fully 40% of women age 40 and over have dense breasts, and cancer is 4-6 times more likely in women with extremely dense breasts than in women with fatty breasts.

A second important note: It is a misconception to assume you have dense tissue because your breasts are firm. However, you cannot gauge breast density by look and feel. Breast density can only be seen/detected via mammograms.

Knowing your breast density matters because the fibrous tissue in your breast appears white on a mammogram screening. Similarly, breast cancer appears white on a mammogram! While mammograms may find some cancers not seen on other screening tests, in cases involving dense breast tissue mammograms will miss more than 50% of the cancers present. Thus the short and sweet version: If you are looking for a white spot on a white sheet of paper, chances are you will never find the spot no matter how good your vision is!

In 2019, Congress passed a National Breast Density Notification Law. (Prior to that 38 states and the District of Columbia separately legislated some form of notification). This new law established national minimum standards to include fibroglandular breast density info on mammography reports. If you are informed that you have dense breast tissue you should discuss with your provider to ascertain whether additional screening is recommended.

Recently, in a webinar we hosted on breast density with Leslie Ferris Yerger from My Density Matters, we discussed the need to encourage these types of conversations between patients and their physicians. It may be recommended that you have an ultrasound, an MRI, or even consider additional screening modalities such as Molecular Breast Imaging, or a 3D mammogram.

At survivingbreastcancer.org we are always in favor of self empowerment/ self advocacy.

In case you missed our webinar, you can view it here.


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