Understanding Dense Breasts and Its Link to Your Cancer Risk
- The U.S. Preventive Services Task Force recommends women at average breast cancer risk begin screening for breast cancer at age 40. Women with the BRCA gene mutation, who have a family history of cancer or have dense breasts, are at higher risk and should talk with their doctor about when to screen which may be younger than 40.
- Women with dense breasts have more fibroglandular tissue and less fatty breast tissue.
- Breast density is determined through mammograms. However, women with dense breasts are at a higher risk for developing breast cancer because dense breast tissue can mask potential cancer during screening.
- While mammograms are extremely valuable for breast cancer screening, more effective screening methods exist for women with dense breasts.
- 3D mammograms, breast ultrasound, breast MRI, and molecular breast imaging are options for women with dense breasts for a more precise screening. It is important to ask your doctor about your breast density and cancer risk.
- The U.S. Food and Drug Administration requires facilities that provide mammograms to tell patients about the density of their breasts. This policy change can directly impact women at higher risk for breast cancer.
Journalist Katie Couric, 66, publicly shared her vulnerable and emotional breast cancer diagnosis a year ago. Amid her journey, she drew more attention to the unique challenges women with dense breasts face. Now, the U.S. Food and Drug Administration requires facilities that provide mammograms to tell patients about the density of their breasts. This policy change can directly impact women at higher risk for breast cancer.
Couric was diagnosed in June 2022 but revealed her cancer to the world during Breast Cancer Awareness Month last year. She was diagnosed with early-stage breast cancer, specifically stage 1A.Read More
Perhaps equally as important is she learned more about her breast during her cancer journey. She has dense breasts, meaning more fibroglandular tissue and less fatty breast tissue exist.
The dense tissue has a “masking effect on how well we can perceive cancer and find cancer on mammograms,” Dr. Cindy Ly, doctor of radiology at NYU Langone Medical Center, told SurvivorNet.
Couric says she receives additional screening alongside her mammogram. She also receives an ultrasound. A breast ultrasound can supplement a regular mammogram in women with dense breasts.
Additional screening methods are helpful for women with dense breasts because glandular tissue appears white on mammograms. Cancer and other abnormalities also exhibit a similar appearance. The “frosted glass” effect from the glandular tissue can thus mask cancerous areas, especially nascent ones. Undetected, these cancers can progress, growing large and advanced. They will then likely require more intensive treatments to cure or can become incurable altogether.
Helping Patients Better Understand Dense Breasts
- How to Avoid False Positive Cancer Results in Women With Dense Breasts: Ultrasounds Used in Addition To Mammograms
- I Have Dense Breasts. Do I Need a 3D Mammogram?
- Millions of Women With Dense Breasts — A New Congressional Law — What You Need to Know
- When You’re Getting a Mammogram, Ask About Dense Breasts
Other Methods to Screen Dense Breasts
Women with dense breasts may not know they have it based on feeling alone. Breast density is determined by its appearance on a mammogram. Dr. Connie Lehman, the chief of the Breast Imaging Division at Massachusetts General Hospital, explains to SurvivorNet that fatty breast tissue appears gray on an X-ray. Conversely, dense breast structures appear white during an X-ray. Cancers also appear white on an X-ray, meaning the dense breast structures can mask the possibility of cancer. Luckily, advanced mammograms exist to help doctors navigate this obstacle.
WATCH: 3D Mammograms explained.
“Digital mammography, it turns out, significantly improves the quality of the mammogram…It’s 3D or tomosynthesis mammography,” Dr. Lehman explains.
“This allows us to find more cancers and to significantly reduce our false-positive rate. With digital mammography 3D tomosynthesis, we’re taking thin slices through that breast tissue, like slices of a loaf of bread. We can look at each slice independently rather than trying to see through the entire thickness of the entire loaf of bread. So those thin slices help us find things that were hidden in all the multiple layers,” Dr. Lehman adds.
Additional testing can be considered for dense breasts, depending on a woman’s personal history, preferences, and her physician’s guidance. These tests include:
- 3-D Mammogram (Breast Tomosynthesis): This technology acquires breast imaging from multiple angles and digitally combines them into a 3D representation of the breast tissue. This allows physicians to see breast tissue architecture better, even in dense breasts. 3D mammograms are fast becoming the standard way of performing mammography.
- Breast Magnetic Resonance Imaging (MRI): An MRI machine uses magnets to create highly detailed, intricate images of the breast. These are mostly reserved for women with an extremely high breast cancer risk. Dense breasts alone may not be a valid reason to obtain a breast MRI. However, dense breasts in women with genetic mutations, like BRCA1 and BRCA2, or a strong family history of breast cancer could justify obtaining breast MRIs.
- Molecular Breast Imaging (MBI): MBI is a newer imaging technique that uses a radioactive tracer to detect breast cancer. It is beneficial for women with dense breasts. However, MBI is not as widely available as other screening methods.
A new rule from the Food and Drug Administration (FDA) says that facilities offering mammograms must notify patients about their breast tissue density and recommend they speak with a doctor to determine if further screening is necessary. There will be “uniform guidance” on what language to use and what details must be shared with the patient to make the communication clear and understandable.
Breast Density Doesn’t Remain the Same Over Time, Impacting Your Cancer Risk
Women with dense breasts are at a higher risk for developing breast cancer. This connection has been demonstrated time and again in several rigorous scientific studies. 1 in 6 women with dense breasts are at risk for breast cancer. Comparatively, 1 in 8 women with average breasts are at risk for this cancer. The exact reason for this difference is not fully understood.
Researchers from Washington University School of Medicine in St. Louis and Brigham and Women’s Hospital in Boston analyzed this connection in a new study.
They recruited 947 women between November 2008 and October 2020. All women were cancer-free at the start of the study and received yearly or bi-yearly screening mammograms. Researchers tracked the women’s mammogram reports and breast densities over time.
All women experienced a decline in their breast density during the 12 years. 289 women developed breast cancer during this time. Those who developed cancer had a lower rate of decrease in breast density than those who did not. The researchers concluded that the rate of breast density changes may indicate future breast cancer risk.
Understanding Your Mammogram Report and Breast Density
A radiologist reading mammograms categorizes breasts into four different categories using the Breast Imaging Reporting and Data System (BI-RADS), a classification system developed by the American College of Radiology (ACR). These include:
- Fatty breast tissue: These breasts are mostly composed of fat with very little dense tissue. Found in less than 10% of women, fatty breasts appear dark on mammograms.
- Scattered fibroglandular breast tissue: These breasts contain a mix of fatty and dense tissue (composed of glands and fibrous tissue). On a mammogram, they have dark areas (fatty tissue) intermixed with light areas (dense tissue). Around 40% of women have breasts that fall in this category.
- Heterogeneously dense breast tissue: This type of breast tissue has many areas of dense tissue and some areas of fat. Found in 40% of women, these breasts look mostly light, with some dark areas on a mammogram.
- Extremely dense breast tissue: Such breasts are almost entirely composed of dense glandular and fibrous connective tissues with very little fat. They are found in 10% of women and appear light on mammograms.
Your breasts are usually called dense on a mammogram report if they fall within the heterogeneously dense breast tissue or the extremely dense breast tissue categories.
When to Screen for Breast Cancer
There is a wide consensus in the medical community that women have annual mammograms between the ages of 45 and 54. However, an independent panel of experts called the U.S. Preventive Services Task Force (USPSTF) is saying that women should now start getting mammograms every other year at the age of 40, suggesting that this lowered the age for breast cancer screening could save 19% more lives. For women aged 55 and older, the American Cancer Society recommends getting a mammogram every other year. However, for women in this age group who want added reassurance, they can still get annual mammograms.
Women with a strong family history of breast cancer, a genetic mutation known to increase the risk of breast cancer, such as a BRCA gene mutation, or a medical history, including chest radiation therapy before the age of 30, are considered at higher risk for breast cancer.
Experiencing menstruation at an early age (before 12) or having dense breasts can also put you into a high-risk category. If you are at a higher risk for developing breast cancer, you should begin screening earlier.
What To Ask Your Doctor
If you have been diagnosed with breast cancer, you may have questions about keeping your strength through treatment. Here are a few questions to help you begin the conversation with your doctor:
- What treatment will I be receiving?
- What side effects are associated with this treatment?
- Are there steps I can take daily to help minimize these side effects?
- What physical activity routine do you recommend for me during treatment?
- Do you have recommendations for someone who doesn’t particularly enjoy exercise?
- Can you recommend a dietician who can help me with healthy eating tips and weight maintenance?
- I’ve been having trouble sleeping. Do you have any treatment recommendations?