Having dense breasts is one of the risk factors associated with breast cancer.
It means you have more glandular and fibrous tissue than fat tissue.
Dense tissue makes it harder to detect breast cancer on amammogramso additional imaging tests may be required.
Verywell / Jessica Olah
Breast density can only be established with a mammogram.
What Are Dense Breasts?
Breasts are composed of fibrous, glandular, and fatty tissue.
It’s a common misconception that dense breasts feel firmer.
Dense breasts are not firmer to the touch.
Only a mammogram read by a medical professional can determine if you have dense breasts.
There are four categories used to describe breast density.
They go in order from least to most dense.
Generally, categories C and D are considered dense breasts.
Categories B and C, scattered and heterogeneously dense breasts, are the most commonmammogram findings.
Causes
Dense breasts are a common mammogram finding.
Nearly half of all females 40 years and older have dense breasts detected on their mammogram.
Some data suggestoral contraceptivescontribute to increased breast density.
If oral contraceptives are started at an earlier age, there may be an association with increased breast density.
Dense Breasts and Increased Risk of Cancer
Dense breasts are associated with an increasedrisk of breast cancer.
This risk is in addition to the fact that dense breasts are more challenging to read on mammograms.
One theory for the increased risk is that dense breasts contain more cells than non-dense breasts.
So, there are more opportunities for abnormal cells to develop.
Individuals with heterogeneously dense breasts are also more likely to develop breast cancer.
Fibrous tissue does not become cancerous.
You may experience breast lumps in the fibrous tissues, known as fibrosis, and cysts.
Collectively these changes are known as fibrocystic changes.
In most females, they are a normal finding.
Complicated and complex cysts have a slightly increased rate of turning cancerous.
Always consult your healthcare provider right away if you notice changes to your breasts.
However, females under age 55 with dense breasts are more likely to developestrogen receptor-negative tumors.
Larger tumors and lymph node involvement are also seen in denser breasts.
While dense breasts are part of this calculation, they are not the strongest risk factor.
Dense breasts are characterized by white areas on a mammogramand so is breast cancer.
Your provider can help you assess your overall breast cancer risk to determine if additional screening is needed.
It is currently only recommended for people who have a high lifetime risk of developing breast cancer.
Unlike mammography, the accuracy of MRI is not altered by dense breasts.
Since abbreviated MRIs are a relatively newer protocol, not all radiology departments can do this screening.
Genetic Testing
Various genes are associated with a higher lifetime risk of breast cancer.
Two genes associated with a significantlyhigher breast cancer riskare theBRCA1andBRCA2genes.
Your healthcare provider can help you determine if genetic testing is appropriate and order genetic tests.
Reporting requirements vary by state.
The U.S. Food and Drug Administration (FDA) regulates mammogram facilities.
Summary
Dense breasts are common and seen in about half of U.S. women who have mammograms.
Dense breasts can obscure breast cancer detection on mammograms.
If you have dense breasts, discuss your overall breast cancer risk with your healthcare provider.
You may need additional imaging tests in addition to an annual mammogram.
Perform a monthlybreast self-examinationand be attentive to changes in your breasts.
Contact your healthcare provider right away if you notice any changes or pain.
American Cancer Society.Breast density and your mammogram report.
National Cancer Institute.Dense breasts: answers to commonly asked questions.
Memorial Sloan Kettering Cancer Center.Breast cancer.
American Cancer Society.Fibrocystic changes in the breast.
Breast Cancer Surveillance Consortium.BCSC tools.
Lee CI, Chen LE, Elmore JG.Risk-based breast cancer screening: Implications of breast density.Med Clin North Am.
2017;101(4):725-741. doi:10.1016/j.mcna.2017.03.005.
2019;21(1):111.
U.S. Food and Drug Administration.Important Information: Final Rule to Amend the Mammography Quality Standards Act (MQSA).
