As a mammogram patient, you may have heard your doctor talk about your breast density, especially if you live in a state that requires disclosing breast density.  But do you know what breast density is and why it matters when it comes to mammogram reading and that artificial intelligence (AI) help you and your doctor better understand your risk of breast cancer and catch any potential cancerous masses earlier?

What is Breast Density, and Why is It Important? 

A woman’s breast has three main types of tissue: fibrous, fatty, and glandular tissue. Fibrous tissue (or supportive or connective tissue) is the tissue that ligaments and scar tissue are made of. Fatty tissue fills the spaces between glandular and fibrous tissue and largely determines breast size. Glandular tissue includes breast lobes and breast ducts tissue (the parts that make milk). A woman with more fibrous and glandular (“fibroglandular”) tissue than fatty tissue has what's called “dense breasts.” As published by the American College of Radiology (ACR) there is a four-category scale that radiologists use to assess how dense a patient’s breasts are, based on the Breast Imaging-Reporting and Data System (BIRADS) atlas. This scale is a standardized reference that radiologists use to report tissue density of mammograms. 

Women are more likely to have dense breasts if they’re younger, pregnant or breastfeeding, take hormone replacement therapy, or have a lower body weight. It can often be an inherited trait and the density of a woman’s breasts usually decreases over time. While every woman is different, breast density in general can be greater in some populations.   

According to the CDC, women with dense breasts have a higher risk of developing advanced breast cancer. This risk is partly because dense tissue can obscure suspicious lesions in a mammogram reading. However, having dense breast tissue is, in itself, an independent risk factor for developing breast cancer. 

How is Breast Density Usually Measured? 

The density of a woman’s breasts greatly affects how easy it is to spot possible cancers in her mammogram, making it very important for both patients and physicians to know if mammograms reveal dense breasts. Knowing breast density is now backed by federal law that requires patients notified if they have dense breasts (Type C: “heterogeneously” or Type D: “extremely” dense) based on the BIRADS atlas. These four types are: 

● A - “Almost entirely fat”

● B - “Scattered areas of fibroglandular density”

● C - “Heterogeneously dense”

● D - “Extremely dense”  Currently, assessment of breast density is subjective. Therefore, there is variability between different readers in making density assessments and density results may vary from year to year on sequential mammograms which can lead to confusion.  

How AI Helps 

Newly developed AI-based technology for breast cancer detection and breast density classification is helping radiologists more quickly identify suspicious mammograms and classify breast density for better, more consistent screening.

Knowledge of breast density is an important factor in calculating an individual patient’s risk for developing breast cancer (known as the Tyrer-Cusick risk score) and helps determine whether additional tests for some patients may be indicated, such as genetic testing or screening breast ultrasound, and breast MRI. 

Check with your doctor to learn more about your Breast Density and ask about AI and that value it can bring in improving cancer detection.

To learn more about how CureMetrix helps doctors in determining breast density in every patient, click here.

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