Demystifying Breast Density: Key Facts and Considerations
Breast density has long been recognised as an independent risk factor for breast cancer—a fact established in research and clinical guidelines for over two decades. In fact, most private radiology providers in Victoria have been reporting breast density for several years as part of routine mammography.
However, it’s only recently—early 2025—that BreastScreen Victoria has joined this practice, rolling out breast density reporting across its entire screening program. Now, when a woman attends BreastScreen Victoria and nominates a GP, her mammogram results will include her breast density category.
While this change marks a positive shift toward more personalised, risk-based care, it has also sparked some confusion—among both patients and GPs. Let’s clarify what breast density means, why it matters, and what steps you should consider next.
What Is Breast Density?
Breast density refers to the amount of fibroglandular tissue compared to fatty tissue in the breast, as seen on a mammogram. It doesn’t reflect how your breasts feel or look—it’s only visible on imaging.
Breast density is categorised into four levels (based on BI-RADS classification):
A: Almost entirely fatty
B: Scattered fibroglandular densities
C: Heterogeneously dense
D: Extremely dense
About 10% of women have extremely dense breasts (Category D), and another 40% fall into Category C.
Why Does Breast Density Matter?
Cancer Detection Challenges (Masking Effect)
Dense tissue can hide cancers on a mammogram, making them harder to detect.Increased Risk
Women with higher breast density have a higher risk of developing breast cancer, although this risk varies depending on additional factors like age, family history, BMI, and hormone therapy use.
What Should You Do If Your Report Mentions Dense Breasts?
1. Don’t panic—most women fall in the middle categories (B or C).
Mammograms still detect most cancers, even in dense tissue.
2. Know your personal risk.
Breast density alone doesn’t define your overall risk. Tools like iPrevent help assess your individual risk by factoring in personal and family history, lifestyle, and more. Be sure to check out my dedicated blog on breast cancer risk assessment.
3. Stay breast aware.
Regardless of your breast density, continue self-checks, report any new symptoms, and attend your screening appointments.
4. Discuss your risk with your GP and/or Breast Specialists.
In higher-risk women (especially with Category D density and other risk factors), options like ultrasound, tomosynthesis, contrast mammography, or MRI may be appropriate. These are not part of the BreastScreen program and require specialist referral.
Your breast specialist may also recommend genetic testing, depending on your personal and family history. During your consultation, they can discuss:
A personalised screening plan based on your risk level
The potential role of risk-reducing medications
Whether preventive surgery should be considered
In summary remember breast density is just one piece of the breast cancer risk puzzle. It can raise questions—but it also opens the door to more personalised, informed care.