Important note: This article is for informational purposes and guidance only. It is not meant to diagnose or assess your individual risk for breast cancer. It should not replace consulting a healthcare provider before making a medical decision.
Dense breast tissue is surprisingly common. Roughly half of women aged 40 and older have dense breast tissue. So, how can you tell if you have dense breast tissue? You cannot determine breast density based on breast size, appearance, firmness, or how your breasts feel during a self-exam.
Most women are notified of breast density following a mammogram. As of September 2024, mammogram facilities in the United States are required by the FDA to provide you with breast-density information following your screening.
Breasts are made up of fatty tissue, fibrous connective tissue, and glandular tissue, including the lobes and ducts. Fibrous and glandular tissue together are often referred to as fibroglandular tissue.
Breast density describes the amount of fibroglandular tissue compared with fatty tissue as it appears on a mammogram.
Breast density is not the same thing as breast firmness. Two women whose breasts look or feel similar can have very different breast densities.
Having dense breasts is not a diagnosis, and it does not mean that cancer has been found. Breast density can also change over time. However, density is important because it can affect both your breast cancer risk and how easily certain abnormalities can be seen on a mammogram.
Radiologists categorize breast density into four categories when reviewing mammograms. Here's how your care provider will discuss your results with you using criteria from the American College of Radiology's Breast Imaging Reporting and Data System (BI-RADS):
Dense breast tissue on its own isn't cause for alarm. However, dense tissue can make screening for cancer more difficult. Dense tissue can make some abnormalities more difficult to see on a mammogram because both dense tissue and some breast cancers appear white.
Having dense breasts alone does not mean a woman will develop breast cancer. When assessing risk, it's important to look at factors like age, family history, genetics, previous breast findings, and lifestyle.
One large cohort study found that the estimated absolute risk of breast cancer after age 50 was 6.2% among the one-third of women with the lowest breast density, compared with 14.7% among the 5% with the highest density.
Meta-analyses have found that women in the highest dense breast category have about a 4–6x higher risk of being diagnosed with breast cancer compared with women with the lowest dense breast category.
For these reasons, breast density is an important factor to discuss with your healthcare provider as part of your overall breast cancer risk and screening plan.
Your breast-density information should be included with your mammogram results.
Depending on your healthcare system, you may find it in your mammogram results, patient summary, radiology report, or patient portal.
It's also important to understand that breast density and your mammogram result are not the same thing. You can have dense breast tissue and still have a normal mammogram result.
If your report does not make your density category clear, ask your healthcare provider whether your breasts are considered dense and whether they fall into category A, B, C, or D.
Review your complete mammogram results to understand whether dense breast tissue was the only notable finding or whether other findings were reported. It's also important to learn if you're among the 10% of women with extremely dense breast tissue or among the 40% with heterogeneously dense tissue.
Your mammogram report may include recommendations for additional imaging or follow-up based on your findings. Your findings also present the perfect opportunity to discover your comprehensive breast cancer risk with a healthcare provider. For some women with dense breasts, a healthcare provider may recommend additional imaging, such as breast ultrasound or MRI, based on breast density and overall risk. If you don't know where to start, here are some questions to bring to your care provider:
Breast ultrasound can provide additional imaging information in women with dense breast tissue. For some women with dense breasts, adding breast ultrasound may help detect findings that are harder to see on a mammogram. Whether additional screening is appropriate depends on breast density, overall breast cancer risk, previous imaging findings, and other factors. It’s important to note that breast ultrasounds do not replace mammograms and should be used together adjacently.
When considering whether breast ultrasound may be appropriate, your healthcare provider can consider factors such as your breast density, overall breast cancer risk, and findings from previous imaging.
HerScan offers comfortable, compression-free, radiation-free breast ultrasounds that can be used as an additional screening alongside recommended mammography.