Dense Breasts Are Common—Here Is What to Know

What Is Breast Density and How Common Are Dense Breasts?
Breast density refers to the amount of dense tissue (like glands and fibrous tissue) you have compared to fatty tissue in your breasts. Dense breasts are very common. About half of all women have them.

Why Does Breast Density Matter?
Dense breast tissue makes it harder for doctors to see cancer on a mammogram because both appear white on the image. Even with dense breasts, mammograms are still the best screening tool for most women and can find most breast cancers. Having dense breasts also slightly increases your chance of getting breast cancer, but not enough on its own to put you in the high-risk category.

How Do I Know If I Am at High Risk for Breast Cancer?
Doctors look at your overall risk—not just breast density—to decide if you are at high risk. Some other important risk factors, beyond breast density, include:

Age: Most breast cancers happen in women older than 50 years.

Family history: Having a close relative (like a parent, sibling, or child) with breast or ovarian cancer—especially if they were diagnosed before 50 years of age—raises your risk.

Certain inherited genes: Some gene variations, like in BRCA1 or BRCA2, raise risk considerably.

Past breast biopsies: Some biopsy results, such as atypical cells, can increase your risk.

Hormone use: Using hormone replacement therapy may slightly raise your risk.

Doctors use special tools (called risk calculators) to estimate how likely you are to develop a disease. They give you a score, like a percentage. If your chance of getting breast cancer in your lifetime is 20% or more, you might be called high risk. Every woman should get a breast cancer risk assessment. It helps you and your doctor decide if you may benefit from extra screening tests.

What Should I Do If I Have Dense Breasts?
Talk to your doctor about all of your personal risk factors—not just breast density. Most women with dense breasts do not need extra tests beyond regular mammograms. If you are at high risk, your doctor may recommend extra screening tests, such as MRI (magnetic resonance imaging) or ultrasonography (this test can be used if MRI is not available, but it is not as accurate). Extra screening tests may lead to more false alarms (finding something that is not cancer), finding cancers that will not cause any problems (this is called overdiagnosis), more tests or treatments that you do not really need, higher costs that might not be paid by insurance, and more worry or stress.

Dense breasts are common and not usually something to worry about. Mammograms are the best way to screen for breast cancer. Extra tests are only needed if you have other risk factors that put you at higher risk. It is important to think about the pros and cons of extra screening based on your personal risk and values. Your doctor can help guide this decision.