Breast Density Measurement and Reporting
The BreastScreen Australia (BSA) Program recommends that women are informed of their breast density as measured on their screening mammogram.
BreastScreen services in some states and territories are already providing information to women about their breast density in their mammogram result. Other jurisdictions are working towards providing breast density information in their mammogram result.
What is Breast Density?
Breast density is a term used to describe the different types of tissue that make up the breast including fatty tissue, glandular tissue (milk ducts and lobules), and connective (fibrous) tissue. Women with dense breasts have higher levels of glandular and connective tissue and lower levels of fatty tissue.
How do I know if I have dense breasts?
Breast density cannot be assessed by a physical examination because it is not related to how breasts look, feel, or their size.
Breast density is usually measured by a mammogram. The healthcare professional (e.g., radiologist) who reads the mammogram will score the women’s breast density against four categories: the lowest (category A) through to the highest (category D).
People with breast density in categories C and D are considered to have dense breasts.
The Breast Imaging Reporting and Data System (BI-RADS) for mammography (fifth edition) is used to describe four categories of density:
- BI-RADS category-A: the breasts are almost entirely of non-dense fatty tissue
- BI-RADS category-B: there are scattered areas of density
- BI-RADS category-C: the breasts are dense, which may obscure small masses
- BI-RADS category-D: the breasts are extremely dense, which lowers the sensitivity of mammography.
The BI-RADS C and D categories are often combined and referred to as ‘dense breasts’. BI-RADS category-D is referred to as ‘extremely dense’.
Why is Breast Density important?
The higher the level of breast density, the harder it can be to detect breast cancer on a mammogram. This is because breast tissue and cancer both appear white on a mammogram.
People with high levels of breast density may have a small increased risk of developing breast cancer, but it is only one of many factors that can influence a person’s overall risk.
What should I do if I have dense breasts?
If you do have dense breasts (Category c or d), talk to your GP. Breast density is only one risk factor for breast cancer. Other risk factors also need to be considered, including family history and lifestyle factors such as smoking, alcohol consumption and being overweight or obese.
Your GP may suggest:
- some lifestyle modifications you can make to reduce your breast cancer risk such as dietary changes or increasing physical activity; and/or
- taking you through an online risk assessment tool; and/or
- some additional tests.
Additional tests may be more invasive than a mammogram and may incur out of pocket costs – please discuss with your GP and the imaging provider.
You can assess your breast cancer risk using a validated risk assessment tool such as ‘iPrevent™’, developed in Australia, Tyrer-Cuzick Risk Assessment Calculator (USA) or CanRisk (UK) prior to deciding to participate in breast cancer screening. These online risk tools can provide the basis of discussion between you and your doctors about reducing the risks of breast cancer and the benefits of participating in mammography screening
More information on risk factors for cancer and some ways to reduce your risk.
BreastScreen Australia recommends women aged 50 to 74 have a mammogram every two years, regardless of breast density. Mammography still detects the majority of cancers and remains the imaging modality for population-based screening for women of all breast densities.
Why we don’t invite you to screen in your 40s
Research and evidence show that most women aged 40 to 49 won’t benefit from regular mammograms. You can speak to your doctor about whether breast screening is right for you.
How is Breast Density measured and reported in the BSA Program?
BreastScreen Australia is delivered jointly between the Australian Government and each state and territory. Some state and territory BreastScreen Programs already measure and report breast density when women have their mammograms. The remainder are working towards reporting breast density.
BreastScreen Programs that currently measure, and report breast density are listed below – for more information, please visit the links:
- BreastScreen South Australia
- BreastScreen Victoria
- BreastScreen Western Australia
- BreastScreen New South Wales
This list will be updated as additional BreastScreen Australia Programs begin to measure breast density in mammogram reports. Information on your local BreastScreen Program is available through the state and territory websites: