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Learning you have dense breasts after a mammogram can raise questions, especially if it’s the first time you’ve encountered the term. The good news is dense breasts are common, not abnormal, and having them does not mean you automatically have breast cancer.

However, dense breasts can both increase the risk of developing breast cancer and make tumors harder to detect on a mammogram. This blog aims to provide clarity around the term by breaking down what dense breasts are, why breast density matters, and what screening options and support are available, so you can feel informed and prepared.

What are Dense Breasts?

Having dense breasts refers to the composition of breast tissue, not how the breast feels or looks. According to the Centers for Disease Control and Prevention (CDC), about 40-50% of women undergoing mammography have dense breasts.

Breasts are made up of two main types of tissue: fatty tissue and Fibroglandular (dense) tissue. Having a higher breast density means you simply have more fibrous and glandular tissue than fat, which is a normal variation in breast anatomy. Research has found dense breasts are most common amongst younger women, people with lower body fat, and those undergoing hormone therapies.

How to Know If You Have Dense Breasts

Dense breasts can not be felt during a self-exam or even a clinical breast exam. Breast density can only be determined through a mammogram, and is defined in the report following your exam. The American Cancer Society details how density appears on your mammogram report, and provides real examples that demonstrate what to look out for.

Why Breast Density Matters for Breast Cancer

People with dense breasts have a higher risk of breast cancer compared to those with mostly fatty tissue, but when understanding your breast density, it’s important to keep this in perspective. Dense breasts are one of many risk factors, not a diagnosis.

Dense breasts can impact screenings as dense tissue appears white on a mammogram, similar to tumors, making them harder to detect. The National Cancer Institute explains that this overlap can sometimes reduce the sensitivity of standard mammography, which is why additional screening may be discussed for some patients.

Breast Density Categories

Radiologists use the BI-RADS system to classify breast density into four categories: Mostly fatty, scattered fibroglandular density, heterogeneously dense, and extremely dense.

Federal regulations now require patients to be notified if they have dense breasts. Mammogram reports now routinely include this information to help patients better understand their results and screening needs.

Screening Options for People with Dense Breasts

Mammography remains an important lifesaving screening, even for people with dense breasts. Depending on your personal risk factors, your health care provider may discuss additional screening options such as: breast ultrasound, breast MRI (typically for higher-risk individuals), or 3D mammography (tomosynthesis)

Screening decisions should always be personalized and made in conversation with your provider.

Talking with Your Health Care Provider: Questions to Ask

If you have been told you have dense breasts, here is a list of questions to ask your medical provider. Having these conversations can help you feel more confident and proactive about your breast health.

• What is my breast density category?
• How does my breast density affect my personal breast cancer risk?
• Should I consider additional screening beyond a standard mammogram?
• How often should I be screened?

How the American Breast Cancer Foundation Can Help

ABCF is dedicated to making breast cancer screenings more accessible to all. Through every step of the process, ABCF is here to help you find answers, navigate coverage, and support preventative care. If you’re not sure about where to get started, learn more about our Breast Cancer Assistance Program and how you may qualify to receive financial support so that cost isn’t the reason you delay or skip care.