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BreastScreen SA will continue to report individual breast density for our clients attending 3 screening locations as we enter the next phase of our research study.

Since February 2022, BreastScreen SA has been conducting research into measuring and reporting individual breast density for our clients as part of our regular breast cancer screening program.

The research study involves 3 screening locations – Arndale, Hyde Park and one of our mobile screening units visiting outer metropolitan Adelaide.

Clients who screen with us prior to 1 August 2022 will be provided with their individual breast density category and invited to complete an anonymous online survey. We hope that the results of this survey will help us to understand what information clients would like about breast density in the future.

While the survey results are being evaluated, we will continue to report individual breast density for our clients attending at 3 screening locations – Arndale, Hyde Park, and one mobile unit. It is currently anticipated that breast density reporting will be extended until May 2024.

Translated information on the study is available here.

You can also a watch a series of videos on breast density and the study here.

Dense breasts

These pictures illustrate the breast density categories as measured using the Breast Imaging Reporting and Data System (ACR BI-RADS® Atlas 5th Edition).

Why is this research important?

BreastScreen SA believes every woman should have an understanding of what breast density is and be aware of her individual risk factors for breast cancer, including her breast density.

The results of this research will help shape future breast care recommendations for women in South Australia.

What is breast density?

Breast density is not a measure of how your breasts feel; it is the amount of glandular tissue in your breasts that appears on a mammogram.

Breasts are made up of 2 main types of tissue – fatty and fibroglandular tissue. Fat appears dark on a screening mammogram while glandular tissue appears ‘dense’ or white – as does breast cancer.

High breast density can increase the risk of breast cancer and can reduce the visibility of breast cancers on a screening mammogram.

How is breast density measured?

A regular screening mammogram is the only way to measure breast density.

BreastScreen SA’s research uses a fully-automated software program, Volpara, to measure your breast density as part of your regular screening appointment. There is no additional time or radiation involved.

Does screening take longer than usual?

No. Your screening appointment will take the usual amount of time, which can be as little as 10 minutes. There will be no change to your regular screening experience.

When will I find out my breast density?

You will receive information about your breast density as part of your screening results letter, usually within 14 days of your appointment. Your nominated doctor will also be notified.

What information will I receive about my breast density?

There are 4 categories of breast density, as measured using the Breast Imaging Reporting and Data System (BI-RADS), American College of Radiology (ACR) 5th edition.

You will be told your breast density category. The 4 categories are:

  • BI-RADS a (around 10% of women): Breasts are almost entirely fatty tissue.
  • BI-RADS b (around 40% of women): Breasts have scattered areas of fibroglandular tissue.
  • BI-RADS c (around 40% of women): Breasts are heterogeneously dense. The mix of non-dense and dense tissue may hide small cancers.
  • BI-RADS d (around 10% of women): Breasts are extremely dense, which can reduce visibility of cancers on mammograms.

Women with BI-RADS c or d classification are regarded as having high breast density.

What if I don’t receive my breast density?

For a small number of women (3-5%), we are unable to measure breast density due to physical restrictions during your screening appointment, an incomplete screen, or the software not generating an accurate reading.

In these circumstances, you will not be offered a repeat screening appointment as it would involve unnecessary additional exposure to radiation. However, you are still included in the research study.

Do I need to do anything else?

Clients who screen before 1 August 2022 will be asked to complete an anonymous online survey. The link to the survey will be provided with your results letter.

We greatly appreciate you taking the time to complete the survey as the success of the research depends on us receiving your valuable feedback.

Clients who screen after 1 August 2022 will not be asked to do anything further. However, you are always welcome to provide your feedback to us by emailing or phoning 13 20 50.

Is it common to have high breast density?

Yes. It is common and normal to have high breast density. In fact, approximately 50% of women, aged 40 to 74 years, have dense breast tissue.

If I have high breast density, do I need additional tests?

BreastScreen SA does not currently recommend additional tests for women with high breast density who have no symptoms or other risk factors for breast cancer.

If you are at higher risk of breast cancer due to other risk factors, such as strong family history or the presence of BRCA 1 or 2 gene mutations, please talk to your doctor about your ongoing breast care.

More information on risk factors is available at

Can breast density change over time?

Yes. Breasts tend to become less dense as women get older, especially after menopause, as the glandular tissue changes and the breasts become more fatty.

Breast density is also influenced by genetic and environmental factors and the hormonal changes that occur throughout a woman’s lifetime, including hormone replacement therapy (HRT) and the combined oral contraceptive pill (COCP).

How is my privacy protected?

All client and participant data is kept strictly confidential in secure locations at BreastScreenSA. Any personal data collected as part of the research will be anonymised. Privacy and confidentiality is strictly maintained at BreastScreen SA.

What if I change my mind about participating in the research?

If you no longer wish to participate, please contact us before your screening appointment on 13 20 50 so that we can book you in for an appointment at another clinic.

All women screened at our 3 participating clinics – Arndale, Hyde Park, and a mobile screening unit – will have their anonymised data included in the research.

However, the research survey that clients are invited to complete after receiving their breast density is both optional and anonymous. While only clients who screen prior to 1 August 2022 will be invited to complete the survey, all clients are welcome to provide their feedback by emailing or phoning 13 20 50.

Where can I get more information?

If you have questions about the research study, please phone 13 20 50 and follow the prompts to our dedicated Breast Density Hotline.

All research in Australia involving humans is reviewed by an independent group of people called a Human Research Ethics Committee (HREC). The ethical aspects of this research project have been approved by the Central Adelaide Local Health Network (CALHN) HREC. This project will be carried out according to the National Statement on Ethical Conduct in Human Research (2007). This statement has been developed to protect the interests of people who agree to participate in human research studies.

If you have any complaints about any aspect of the project, the way it is being conducted or any questions about being a research participant in general, then you may contact the CALHN HREC Executive Officer on 08 7117 2229 or email