You may have heard that some women have what’s called dense breast tissue. In fact this is very common—about half of all women over 40 have dense breast tissue. If your breasts have a lot of glandular and connective tissue, and not much fatty tissue, your breasts may be considered to be dense.
For a definitive evaluation of breast tissue, you need to have a mammogram. On a mammogram, glandular and connective tissue shows as white, and fat shows as black. Depending on the balance of these types of tissue, radiologists classify breast density as follows:
- Almost entirely fatty: The breast consists mainly of fat tissue (very low breast density).
- Scattered fibroglandular: A large proportion of the breast consists of fat tissue, and there are a few areas of dense glandular and connective tissue.
- Heterogeneously dense: The breast has more glandular and connective tissue in it than fat tissue.
- Extremely dense: The breast is almost completely made up of glandular tissue and connective tissue (very high breast density).
Your breast density status, “dense” or “not dense,” will be stated on the written mammogram report that your doctor receives and on the letter that you receive in the mail within 10 business days of your mammogram.
- Slightly higher cancer risk. Compared with women who have low breast density, women with dense breast tissue are slightly more likely to develop breast cancer. Your breast density should be considered as a part of your general breast cancer risk profile in your talks with medical providers.
- You may need imaging in addition to your mammogram. Having highly dense breasts can mean that it is harder for radiologists to find breast cancer on a mammogram. This is because the glandular and connective tissue shows up as white on the mammogram, but so does cancer. Types of imaging that can “see through” dense breast tissue include abbreviated breast MRI, breast MRI, and ultrasound.
- You need to talk to your doctor about assessing your risk for breast cancer. All women should do this. If you have dense breast tissue, this fact should be a part of your discussion with your doctor that includes family history, personal cancer history, breast density, and genetic mutations.