BreastScreen ACT is working towards providing breast density information as part of your screening results.

Breast density is a normal difference in how breast tissue looks on a mammogram. It is one of many factors that can affect a person’s risk of breast cancer.

Not reporting breast density does not increase your risk of developing breast cancer.

What is breast density?

Breasts are made up of fatty tissue and dense tissue. Dense tissue includes the milk ducts, glands and supportive tissue in the breast.

Breast density describes the amount of dense tissue compared to fatty tissue.

You cannot tell how dense your breasts are by their size, shape of how they feel. Breast density can only be assessed through a mammogram.

For many women, breast density changes over time and decreases with age.

Why is breast density important?

Breast density is common and is considered a normal variation in breast tissue.

Having dense breasts can:

• make it harder to see some cancers on a mammogram
• be associated with a higher risk of developing breast cancer.

Is breast density a risk factor for breast cancer?

Breast density is one of many factors that can affect breast cancer risk.

Factors that you cannot change include:

• age
• family history of breast cancer
• genetics
• reproductive history

Factors you may be able to change include:

• being overweight
• not being physically active
• drinking alcohol.

What should I do?

All eligible women should attend regular breast screening appointments, regardless of breast density.

If you have questions about your breast density or would like to better understand your personal risk of breast cancer, speak with your GP.

How is breast density measured?

Breast density is measured using a standard system called Breast Imaging Reporting and Data System (BI-RADS).

There are four breast density categories:

• Category A (least dense): the breasts are made up mostly of fatty tissue
• Category B: the breasts are mostly fatty with some areas of dense tissue
• Category C: the breasts are mostly dense tissue with some fatty tissue
• Category D (most dense): the breasts are made up almost entirely of dense tissue

Categories C and D are considered dense breasts.

In some cases, it may not be possible to assign a breast density category due to technical limitations.