Dense Breasts

Mammogram of dense breast tissue

What does it mean to have dense breast tissue?

Breasts are made up of a mixture of glandular, fibrous, and fatty tissue. If you have a lot of glandular or fibrous tissue but not much fat, your breasts are considered dense. There is little change in most women, but the density may change as you age.

It is important to know if you have dense breasts. The radiologist who reads your mammogram will determine if you have dense breasts. Breasts density is classified using a 4-level density scale.

The categories are:

  1. almost entirely fatty
  2. scattered areas of fibroglandular density
  3. heterogenously dense
  4. extremely dense

Seen in about forty percent of women, dense breast tissue is normal, however, there is a slightly increased risk of breast cancer. Cancers may be obscured and hidden in dense breasts because the sensitivity of mammography decreases by 15-20% with dense breast tissue. Dense tissue is seen as white on a mammogram, as do lumps whether they are benign or cancerous.

The addition of ultrasound to your annual screening mammogram has been shown to increase cancer detection by over 30% for invasive breast cancers less than 10 mm in size. If you have a family history of breast cancer and dense breast tissue, adding ultrasound and MRI to your annual exam should be strongly considered. Another significant imaging test is the 3D mammogram. It is revolutionizing breast care. The 3D imaging allows our radiologists to see the breast tissue layer by layer, one millimeter at a time. This technology is extremely useful for women with dense breasts.

Yearly mammograms beginning at age 40 are recommended by the American Cancer Society, American College of Radiology, Society of Breast Imaging, and the American College of Obstetricians and Gynecologists. 3D imaging is recommended for women with dense breasts. Other risk factors that encourage the use of 3D breast imaging are a family history of breast cancer, previous chest radiation treatment for cancer, previous breast biopsies that diagnose you with a higher risk of breast cancer.

Consult your referring physician and make a decision together about whether or not the additional imaging services are right for you and your health history.