The link between breast density and cancer risk
Dense breasts are a hidden cancer risk affecting about half of all women over 40. Here’s what you need to know.
In the battle against breast cancer, early detection is the key to improving survival rates.
That’s why regular self-examination and mammograms are so important.
Age, family history and lifestyle are all well-known risk factors that can increase your chances of developing breast cancer.
But there’s another risk that often goes under the radar: breast density.
What is breast density?
About 50 per cent of women aged 40 to 74 have dense breasts, with around 10 per cent falling into the extremely dense category.
But you can’t tell by look or feel.
“Breast density is not based on size or firmness; it means there is more glandular and connective tissue compared with non-dense fatty tissue in your breasts,” Breast Cancer Network Australia policy and advocacy director Vicki Durston says.
While breast density is more common in younger women, some women may have dense breasts at any age.
“Some factors that may be associated with higher breast density include using menopausal hormone therapy and having a low body mass index (BMI),” Vicki says.
Breast density and breast cancer detection
Like tumours and other abnormalities, dense breast tissue appears white on a mammogram, consultant breast surgeon Associate Professor Sanjay Warrier says.
“As a result, having dense breasts can make it harder to detect abnormal changes on a mammogram and thereby detect an early cancer,” Assoc Prof Warrier says.
“Breast density is also a risk factor for interval cancers found in between the two-year screening period.”
Does regular screening report on breast density?
So, will you be told about your breast density during a regular screening?
The short answer is it depends on where you live.
Currently, BreastScreen WA is the only regular service that notifies women about breast density.
BreastScreen SA is conducting a study on measuring and reporting breast density, while BreastScreen Victoria supports further discussion and research.
BreastScreen Victoria chief executive Rita Butera says for women aged 50 to 74 who do not have symptoms, a breast screen every two years is the best way to detect breast cancer early.
“We encourage women to regularly check for any changes to their breasts and seek advice from their doctor to make informed decisions,” Rita says.
Vicki says Breast Cancer Network Australia wants women to be informed about breast density through regular screening.
“There is currently no consistency across the country, and we all have a right to know,” Vicki says.
She urges anyone with concerns to consult their GP about density mapping options.
How breast density is mapped
In Australia, density mapping is performed using three main methods, Assoc Prof Warrier says.
“We have great new ways of reducing the likelihood of missing cancers in dense breast tissue by performing 3D mammograms rather than the standard methods,” he says.
Another promising approach involves contrast-enhanced mammography, where a dye is injected during the procedure to make it easier to see abnormal lesions.
MRI screening can also be used to assess breast density, Assoc Prof Warrier says.
“As a breast surgeon, we really want to detect cancers as early as possible,” he says.
“Informing patients of their options and getting them to understand the nuances of screening is an important aspect of that.”
More on breast cancer and women’s health:
- The truth about common breast cancer myths
- Top 10 health checks for women, and when to have them
- The ultimate women’s guide to staying in peak health
Written by Dimity Barber.
