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Oct. 16, 2023—If your mammogram revealed that you have dense breasts, you might be wondering what that means for you. Here are answers to some common questions, based on information from the American Cancer Society (ACS), the National Cancer Institute and other experts.

Q. What are dense breasts?

Breasts are made up of three different kinds of tissue: fibrous, glandular and fatty. When seen on a mammogram, fibrous and glandular tissues look denser than fatty tissue. If your breasts have more of these two types of tissue than fatty tissue, then you have dense breasts.

You can't feel whether you have dense breasts. The doctor who reads your mammogram determines this. If the doctor sees that you have dense breasts, they will note it in the mammogram report.

Q. Why is breast density important?

Dense breasts are common—almost half of women 40 and older who get mammograms have them. They are not abnormal, and they don't cause disease. But they do make it harder for a radiologist to find signs of cancer on a mammogram. Dense breast tissue and abnormal breast changes, such as lumps, both appear white on a mammogram.

And, according to the ACS, women with dense breasts have a higher risk of breast cancer than women who don't have dense breast tissue. Researchers don't yet understand why this is so.

Q. What does having dense breasts mean for me?

The first step: Talk to your doctor about breast density and your overall breast cancer risk. Each person's health situation is different. Your doctor is the best person to assess your risk based on your personal and family history.

You and your doctor can decide if you might need to change your breast cancer screening routine. Depending on your needs, your doctor might recommend:

• 3D mammography. This type of mammogram provides images of the breast in several "slices" from different angles. It can make some abnormal changes easier to spot.
• Breast ultrasound. This machine uses sound waves to make pictures of breast tissue.
• Magnetic resonance imaging (MRI). MRI uses a magnet connected to a computer to make detailed pictures of the breast.

However, both ultrasound and MRI can find things that are not cancer. These findings might lead to more follow-up testing. Ask your doctor about the risks and benefits.

Sources

• American Cancer Society. "Breast Density and Your Mammogram Report." https://www.cancer.org/cancer/types/breast-cancer/screening-tests-and-early-detection/mammograms/breast-density-and-your-mammogram-report.html.
• American College of Radiology. "Breast Density: Breast Cancer Screening." https://www.acr.org/-/media/ACR/Files/Breast-Imaging-Resources/Breast-Density-bro_ACR_SBI.pdf.
• Centers for Disease Control and Prevention. "What Does It Mean to Have Dense Breasts?" https://www.cdc.gov/cancer/breast/basic_info/dense-breasts.htm.
• National Cancer Institute. "Dense Breasts: Answers to Commonly Asked Questions." https://www.cancer.gov/types/breast/breast-changes/dense-breasts.