Dense breast tissue is commonly found during regular mammograms. Your breast is made of glandular, connective and fatty tissue. Dense breasts have more glandular and fibrous tissue and less fatty tissue. This can make it difficult to see potential cancer on mammograms.
Dense breast tissue refers to the amount of fibroglandular and fibrous connective tissue that’s present within your breast as compared to fatty tissue. When there’s more glandular and fibrous tissue than fatty tissue, your breast is considered dense. Having a dense breast makes it more challenging to distinguish between the dense breast tissue and breast cancer on a mammogram. Both dense breast tissue and potential cancers appear as a white spot on a mammogram. Having dense breasts is common.
Your breasts are made of three kinds of tissue:
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Breast density matters because:
Breast density is divided into four types, ranging from having very little dense tissue to extremely dense tissue. The four categories are:
|A||Mostly fatty tissue||Your breast tissue is almost entirely fat.||About 10%|
|B||Scattered fibroglandular breast tissue||You have a mix of dense and fatty tissue, but the majority is fatty.||About 40%|
|C||Heterogeneously dense breast tissue||You have a mix of dense and fatty tissue, but the majority is dense.||About 40%|
|D||Extremely dense breast tissue||Your breast tissue is almost all dense.||About 10%|
|Mostly fatty tissue|
|Your breast tissue is almost entirely fat.|
|Scattered fibroglandular breast tissue|
|You have a mix of dense and fatty tissue, but the majority is fatty.|
|Heterogeneously dense breast tissue|
|You have a mix of dense and fatty tissue, but the majority is dense.|
|Extremely dense breast tissue|
|Your breast tissue is almost all dense.|
If your breast tissue is mostly fatty (A) or scattered fibroglandular (B): You have low breast density, and cancer is more likely to be visible on a mammogram.
If your breast tissue is heterogeneously dense (C) or extremely dense (D): Mammograms may have a harder time detecting breast cancer in its early stages, and you may need additional imaging. This is considered high breast density.
Having dense breast tissue is common. About 50% of women and people assigned female at birth (AFAB) have dense breast tissue.
Having dense breasts is something to discuss with your healthcare provider. It needs to be taken in context of other breast cancer risk factors. Your provider may recommend or offer supplemental imaging.
Dense breasts are more common if you:
Healthcare providers can’t diagnose dense breasts by performing a breast exam. Firmer breasts don’t mean you have dense breasts. Only mammograms can reveal how dense your breasts are.
The radiologist reading your mammogram is required to describe your degree of density. The dense glandular tissue will look white, and fatty tissue will look dark on your mammogram. The more white areas the radiologist sees on the image, the denser your breast.
Each type of imaging has its pros and cons. For instance, while MRIs and ultrasounds can identify cancers that mammography misses, they can also mistake noncancerous cells for cancerous ones (a false positive). Your healthcare provider can talk to you about your options and what they recommend based on your risk for breast cancer and the results of your mammogram.
Breast density can change throughout your life. Some people’s breasts become more fatty (less dense) as they get older, but some people may have no change in their density.
The only way to decrease the density of your breast tissue is to take preventive tamoxifen, a medication reserved for people at increased risk for breast cancer.
Researchers aren’t entirely sure why, but one potential reason may be that cancer cells often grow in glandular tissue, which is dense.
Breast cancer is a common type of cancer that affects women and people AFAB. The majority of people who develop breast cancer don’t have any known risk factors. This is why screenings are so important.
Some of the risk factors can include:
You should still get a mammogram if you have dense breast tissue. Mammograms have been shown to decrease the mortality associated with breast cancer. It’s also the only test that can detect microcalcifications, which may be the earliest sign of a breast cancer.
Discuss both your breast density and your risk factors for breast cancer with your healthcare provider when deciding when to start and how often to get regular mammograms. If you have dense tissue, your provider may suggest a 3D mammogram which has increased breast cancer detection rates, especially in people with dense breast tissue.
You shouldn’t worry. But if you have dense breast tissue, you should speak with your provider about cancer screening options. About 1 in 8 women and people AFAB will develop cancer in their lifetime. Extremely dense breast tissue is one factor that determines risk. Other risk factors, including your family history and sometimes genetic predisposition, can help determine if you qualify for supplemental breast MRI in addition to a yearly mammogram.
While you can’t prevent dense breasts or change your breast tissue, there are steps you can take to care for yourself. Besides talking to your provider about additional imaging, you can:
A note from Cleveland Clinic
If you have dense breasts, it means a radiologist may have a harder time detecting cancer on your mammogram. Dense breast tissue is common and normal. Speak with your healthcare provider about your breast density after your mammogram. Get clarity about what your density means. Your provider may recommend additional breast cancer screenings to get a better look at your breast tissue. Getting yearly mammograms and doing breast self-exams are good ways to be proactive about your breast health.
Last reviewed by a Cleveland Clinic medical professional on 11/30/2022.
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