What is breast density and why does it matter?
Breast density is something every woman should understand — and most don’t think about it until they see it in their mammogram results. Along with regular mammograms and breast self-exams, knowing whether you have dense breasts can affect how your results are read and what follow-up steps your doctor may recommend.
What makes a breast dense?
Breasts are made up of two types of tissue — fatty tissue and fibrous or glandular tissue. Dense breasts have more fibrous and glandular tissue and less fat. This is not something you can feel. Breast density is only determined by how breast tissue appears on a mammogram.
How common is dense breast tissue?
Breast density falls into four categories on a scale used by radiologists. Most women fall somewhere in the middle.
- 10% of women have almost entirely fatty breasts
- 10% have very dense breasts
- 80% fall somewhere between the two
Why does breast density matter?
Dense tissue and tumors both appear white on a mammogram, which can make abnormalities harder to spot. Women with dense breasts also have a slightly higher risk of developing breast cancer, though the reason for this is not fully understood.
If your mammogram shows dense breast tissue, you will receive information about breast density along with your results. If your radiologist recommends additional imaging, such as a 3D mammogram, an ultrasound, or an MRI, your provider can help you understand your results and next steps.
How does 3D mammography help?
Standard 2D mammography can be less accurate for women with dense breasts because dense tissue can obscure what the radiologist is looking for. 3D mammography, also called digital breast tomosynthesis, takes images from multiple angles, making it easier to see through dense tissue and spot abnormalities that a 2D image might miss. It also reduces the likelihood of being called back for additional imaging.
What should you do if you have dense breasts?
Talk to your doctor. Together, you can review your health history, your mammogram results, and whether additional screening is right for you. Even women with entirely fatty breasts and low overall risk should still get an annual mammogram starting at age 40.