Does Breast Density Increase Your Cancer Risk?
Women with dense breasts may require additional testing
Women with dense breasts may require additional testing
Nearly half of all women age 40 and older who get mammograms are found to have “dense” breast tissue. It’s a common condition, but what does it mean? And is there a connection between breast density and breast cancer risk?
Breast density refers to the various types of tissue that make up a woman’s breast as seen on a mammography exam. Breasts contain several types of tissue: glandular, connective and fatty. Dense breasts have more glandular and connective tissue and less fatty tissue than non-dense breasts, but they are not abnormal.
Several factors may contribute to breast density, including heredity. Women who have a low body mass index or use hormone replacement therapy during menopause may have higher breast density. Density may decrease with age.
When should mammograms begin?
Scripps recommends women who are at average risk for breast cancer start annual mammogram screening at age 40. Women who have risk factors for breast cancer should begin screening sooner, have additional tests or get screened more often.
How does a woman know if she has dense breasts?
Dense breast tissue isn’t something that can be seen or felt during a breast exam. Rather, when a woman has a mammogram, the radiologist will determine whether she has dense breasts by viewing the different types of tissue and using the Breast Imaging Reporting and Data System (BI-RADS) to classify the density into one of four categories:
- Entirely fatty breast tissue is almost all fatty breast tissue.
- Scattered fibroglandular breast tissue is mostly fatty tissue with some areas of dense glandular and fibrous connective tissue.
- Heterogeneously dense breast tissue has many areas of dense glandular and fibrous connective tissue, with some areas of fatty tissue.
- Extremely dense breast tissue is almost all dense glandular and fibrous connective tissue.
If your doctor or mammography report says you have dense breasts, you have either heterogeneously or extremely dense breast tissue.
Breast density and cancer risk
While having dense breasts is not considered a medical problem, it can increase a woman’s risk of developing breast cancer.
“Women with dense breasts have a higher risk of breast cancer than women with fatty breasts,” says Sara Kim, MD, breast cancer surgeon at Scripps Cancer Center and Scripps Clinic. “However, breast density has no effect on breast cancer survival rates. Breast cancer patients with dense breasts are no more likely to die from breast cancer than those who have fatty breasts.”
Breast density and mammography results
Breast density can also affect breast cancer detection, as mammography results may be more difficult to interpret in women who have dense breasts.
Fatty breast tissue appears dark on a mammogram, but both dense breast tissue and some abnormal breast changes can look white. This means tumors and other abnormalities are more likely to be missed when the mammography films are read. Because of this, women who have dense breast tissue may be called back for additional testing more often than women with fatty breast tissue.
“Some women feel anxious or worried when we ask them to come back for more testing, but that doesn’t necessarily mean we saw something abnormal,” says Dr. Kim. “Especially with dense breast tissue, we may want to do another mammogram to get a different view of the area or order additional tests like ultrasound or MRI to confirm the mammogram results.”
If you have questions about breast density, breast cancer screening or your cancer risk, be sure to ask your doctor. They can let you know more about your risk and what types of screenings are right for you.
While self-breast exams cannot detect breast density, they are still important as new abnormalities may present themselves in the time period between mammograms.
“In addition, it empowers women to know what their breasts feel like and if something new does show up, a targeted mammogram and ultrasound can be performed to provide more clarity on what was felt,” Dr. Kim says.