Breast Cancer Awareness – Why it Matters if You Have Dense Breasts

So, you may have noticed over the last few years that your mammography report says that you have dense breast tissue. This is because since March 2023, the Food and Drug Administration (FDA) issued a new rule that requires that patients’ breast density be included in their report. The reports now describe the patient’s breast tissue as either dense or not dense. Depending on your state, you may have already seen this designation in your report, but for others of you, this may be relatively new. This is important as “about 50% of women in the US who have screening mammograms are diagnosed with dense breasts.”

According to the American College of Obstetricians and Gynecologists (ACOG), women with dense breasts have an increased risk of breast cancer. Conventional mammograms can be less accurate in women with dense breasts. According to Dr. Melissa Durand, Associate Professor of Radiology & Biomedical Imaging at Yale Cancer Center, that number can drop from 98% accuracy in women with fatty breast down to 30% in women with extremely dense breasts. That is a large difference that underscores the importance of knowing whether a woman has dense breast tissue so that she can receive the type of screening that she needs to accurately detect the presence or absence of breast cancer. Yale Medicine indicates that “women with dense breasts should be aware that it can make it difficult for screening mammography to detect tumors.” It is imperative that this be considered during screening because early detection saves lives.

So, what are dense breasts and why do we need to know about them? Dense breasts are those that do not have a lot of fatty breast tissue. Instead, they have more glandular and connective tissue. When their image is captured on a mammogram, they appear white. This makes detecting cancer on the mammogram images difficult because cancer also appears white in mammogram images. There are no alternative screening tests for women with dense breasts, and women are still recommended to receive regular screening mammograms. Women with dense breasts are recommended to receive 3D mammograms, also known as breast tomosynthesis. Three dimensional mammograms take multiple images of the breast from several angles that can be reviewed by radiologists for detection. They have been shown to have better cancer detection rates with fewer false positive results. In addition to 3D mammograms, women diagnosed with dense breasts should discuss their results with their doctors to determine if  further screening tests (e.g., breast ultrasound or MRI ) are necessary based upon their breast cancer risk.

For more on dense breast tissue, check out this video from the Mayo Clinic:

Mayo Clinic Minute – What does a dense breast tissue diagnosis mean?

References

American College of Obstetricians and Gynecologists. 2015. Management of women with dense breasts diagnosed by mammography. Committee Opinion No. 625. Obstet Gynecol 2015;125:750–1.

American College of Obstetricians and Gynecologists. 2023. The U.S. Food and Drug Administration requires notification of breast density in mammography reports. Practice Advisory. Retrieved from https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2023/04/us-food-drug-administration-requires-notification-of-breast-density-in-mammography-reports

Yale Medicine. 2025. Dense Breasts. Retrieved from https://www.yalemedicine.org/conditions/dense-breasts