Breast Density and Dense Breasts
Breasts are made up of different types of tissue; there are dense fibrous and glandular, and less-dense fatty tissues. Each woman has their own unique combination of these tissues. Some have enough dense tissue to be classified as having "dense breasts."
No, dense breasts are not uncommon. In fact, about 50% of women have dense breasts. About 10% of women have "extremely dense" breasts, while 40% of women have a level of density called "heterogeneously dense".
Since April 1, 2013, California law (Senate Bill 1538; Section 123222.3 of the Health and Safety Code) requires imaging centers to notify patients who have dense breasts. The law states:
"A health facility at which a mammography examination is performed shall, if a patient is categorized by the facility as having heterogeneously dense breasts or extremely dense breasts, based on the Breast Imaging Reporting and Data System established by the American College of Radiology, include in the summary of the written report that is sent to the patient, as required by federal law, the following notice:
Your mammogram shows that your breast tissue is dense. Dense breast tissue is common and is not abnormal. However, dense breast tissue can make it harder to evaluate the results of your mammogram and may also be associated with an increased risk of breast cancer.
This information about the results of your mammogram is given to you to raise your awareness and to inform your conversations with your doctor. Together, you can decide which screening options are right for you. A report of your results was sent to your physician."
Higher levels of density may make it more difficult for a mammographer to detect breast cancer—dense tissue is simply harder to see through on a traditional x-ray mammogram, and areas of higher density can look much like tumors.
Yes. Mammography is still the gold-standard for breast-cancer detection. In fact, there are types of cancers which only show up on mammograms. You should continue to follow the guidelines for mammography based on your age, your risk-factors, and your doctor’s advice.
At this time, mammography remains the only recommended breast-cancer screening exam. There are, however, secondary screening options, such as automated whole breast ultrasound. If you are interested in an automated whole breast ultrasound, you should discuss them with your regular physician.