#BreastKeptSecret aims to help spread knowledge among women about the importance of knowing your breast density. Use this resource to get abreast of the latest information and help to ensure your friends and family are in the loop.

Q. Why is breast density important?

A. International clinical research shows women with high breast density (HBD) are at a greater risk of developing breast cancer, and also at a greater risk of breast cancer not being detected by a mammogram.

Q. What is breast density?

A. Breasts are made up of different types of tissue: fatty, fibrous and glandular. Fibrous and glandular tissue appear white on a mammogram and fatty tissue shows up as dark. If most of the tissue on a mammogram is fibrous and/or glandular, the breasts are said to be dense.

Q. How does breast density affect mammograms?

A. Dense breast tissue appears white on a mammogram, as does cancer. This can make it hard for a radiologist to detect early stage breast cancer on a mammography image.

Q. Is it common to have dense breasts?

A. Dense breast tissue is common among women and usually reduces over time with age.

Q. Is breast density a risk factor for breast cancer?

A. Women with extremely dense breasts are two to six times more likely to develop breast cancer over those with extremely fatty breasts.

Q. Should I continue to get mammograms?

A. It’s important to continue to have regular mammograms as mammography is the standard screening test for breast cancer and is proven to reduce deaths due to breast cancer.

Q. How do I know if I have dense breasts?

A. Breast density is not something you can feel through touch. It can only be determined by a specialist doctor (called a radiologist) through a breast screen e.g. a mammogram.

Any woman over the age of 40 who has had a mammogram can ask their doctor for details about their breast density. Not all mammograms though will provide a report on breast density as it is not currently required in Australia, except in Western Australia.

Q. What do I do if I have dense breasts?

A. Those in the higher breast density categories can speak with their doctor about what may be most appropriate for them going forward. This may include additional screening tests such as Ultrasound or MRI, which can include an additional cost.

How are dense breasts categorised?

Once a woman has undergone a mammogram it is possible for the radiologist to “categorise” the breast tissue into one of four categories. The first two categories are less dense while the last two categories are the higher density groups. In Australia*, these categories are defined in the following way:

  • Category 1. Predominantly Fatty Breast
  • Category 2. Scattered Fibroglandular Breast
  • Category 3. Heterogeneously Dense Breast
  • Category 4. Extremely Dense Breast

*You may notice that in the United States these categories are defined as A to D, as per the BIRADS® Atlas 5th Edition.