If you recently had a mammogram and were told you have dense breasts, you probably have some questions about what this means and how it affects your breast cancer risk and future exams. It's important to know that dense breast tissue is common and may never cause additional problems.
Breast density is a term used to describe the types of tissue that make up your breasts. Simply put, dense breasts have more connective and breast (glandular) tissue than fatty tissue. These different types of tissue show up differently in the images created during a mammogram. Connective tissue makes it difficult for a doctor to determine whether you have any tumors. Therefore, you may be required to have additional testing for doctors to get a better view and an accurate screening for breast cancer.
While there are a number of factors that may cause dense breast tissue, there is nothing you can do to prevent it. Your breast density comes from a combination of your genetic makeup and your age. Breast density can even change over time, and breast tissue often becomes less dense as you age. Here are the most common reasons women have dense breasts:
Your mammogram report will include an assessment of masses, lumps, distorted structures, or calcifications found in the breasts, as well as an assessment of breast density. After a radiologist reviews your images, your doctor will discuss the results with you and recommend more tests if necessary.
In March of 2023, the Food and Drug Administration (FDA) amended the Mammography Quality Standards Act (MSQA) of 1992, which requires your doctor to disclose information regarding the density of your breasts. By September 2024, all mammogram reports sent to patients in the US will be required to include breast density described as either “not dense” or “dense”. Having this information will allow you to have conversations with your doctor about your specific risk for breast cancer.
Dense breasts affect your cancer risk in two main ways:
Studies have shown that women with dense breast tissue are four to six times more likely to develop breast cancer than those with mostly fatty breast tissue. This risk increases with the amount of dense tissue found in your breasts. While the reason for the connection is currently unknown, it's important to remember that breast density alone does not determine breast cancer risk. It is only one of the many risk factors related to breast cancer.
Tumors can often go undetected in women with dense breasts because small areas of cancer can hide behind the dense breast tissue, appearing the same color on the mammogram. It's widely known that early detection of breast cancer is a vital step in successful treatment. Therefore, your doctor may suggest you have additional tests if you have extremely dense breast tissue.
Breast density isn't something you can feel or diagnose on your own. It must be determined by a mammogram. The fatty breast tissue appears dark on mammogram images. Dense or fibrous tissue appears white. This is an effective way to determine breast density, but tumors and other abnormalities also look white on your mammogram. This similar appearance makes abnormalities difficult to detect.
Mammograms are still considered the most effective way to screen for breast cancer. The test is performed by a mammogram technologist (mammographer). When the mammogram is complete, the images are reviewed by a radiologist. After your breast density is determined, your doctor can decide if you need additional tests.
It's important to talk with your doctor about the best screening plan for your personal situation. Your doctor will consider your risk factors and protective factors that may lower your chance of breast cancer before recommending further tests. Common imaging tests include:
Dense breasts are only one risk factor for breast cancer. However, increased breast density can make your screening mammograms more difficult to read. Understanding your risks for breast cancer is an important way to help your doctor detect abnormalities. If you have questions about breast density, you need to talk with your doctor about your personal risks. Discussing your options for additional screening can help you detect abnormalities and tumors before they become aggressive.