Until a few weeks ago, Brenda, 52, only had two mammograms — once when she turned 40 and again when she turned 50. Both came back clear.
At a third mammogram in September, things seemed normal until she received a phone call two days later.
“I got a call back … requesting I have another mammogram and ultrasound of my right breast,” said Brenda, who declined to use her last name in order to protect her privacy.
Brenda called her family doctor for clarification, and she was told she had “two dense patches” in her right breast that needed a “closer look.”
“It was pretty unnerving,” she said. She was told nothing about how dense her breasts are or what that could mean for her breast cancer risk.
According to Dense Breasts Canada, 43 per cent of women ages 40 to 74 have dense breasts — a startling number, considering the implications they can have for a person’s risk of developing breast cancer and screening procedures.
What are dense breasts?
Breasts are composed of fat, glands and fibrous tissue, but the proportions of each will vary from person to person, the organization noted.
If a breast is composed of 50 per cent or more glands and fibrous tissue, it is considered dense.
There are four categories of breast density, determined by how much fatty tissue a person has: Category A (almost entirely fat), Category B (scattered densities), Category C (heterogeneously dense) and Category D (extremely dense). The labels used vary from province to province.
“They’re all normal … There is no typical breast,” said breast density expert Dr. Paula Gordon, a clinical professor in the Department of Radiology at the University of British Columbia.
“Unlike other parts of the body — like if you look at a chest X-ray, everybody’s chest X-ray looks about the same — but ‘normal’ breasts vary tremendously in how they look.”
You can’t tell if your breasts are dense by look, feel, size or firmness. Breast density can only be detected by the radiologist reviewing your mammogram, according to Lothar Lilge, a senior scientist at the Princess Margaret Cancer Centre.
However, British Columbia is currently the only province to add density information to mammogram results. In all other provinces, radiologists don’t tell people their breast density category.
This concerns experts because dense breasts can have serious implications.
Why it matters if you have dense breasts
There are two main consequences of having dense breasts. The first is that they have been shown to increase a person’s risk of developing breast cancer.
A 2017 study found having dense breasts to be the most prevalent risk factor of breast cancer in women. According to researchers, women whose breasts have more glandular tissue than fat are twice as likely to develop breast cancer.
“It’s a rather strong risk factor … not as strong as age or known genetic mutations, but a strong risk factor,” Lilge said.
The second consequence of dense breasts is that they make it difficult to see breast cancer with a standard mammogram — a phenomenon Gordon calls “the masking effect.”
There are several ways to detect cancer early in dense breasts, but only two are “widely available”: ultrasound and MRI.
Early detection is key to beating the disease, which is why doctors encourage an awareness of risk factors — like family history and obesity — as well as frequent screenings.
Finding cancer early can save lives, but it can also allow a woman to have a lumpectomy instead of a mastectomy. It can even mean avoiding chemotherapy.
“That’s a pretty big deal,” said Gordon.
Since people with extremely dense breasts require screening beyond mammograms to detect cancer early, Gordon believes most provincial breast cancer screening programs are due for an upgrade.
Calls for an updated screening process
Because it may be harder to detect cancer in dense breasts, Dense Breasts Canada wants the health-care system to increase screening procedures and provide ultrasounds for those most at risk — including those with the densest breasts.
In Quebec, an ultrasound is given as a supplementary screening procedure if you’re in the highest category of breast density and have a family history of the disease.
British Columbia was the first province to add density information to its mammogram results.
“Your postal code should not determine whether or not you have access to early detection for breast cancer,” Jennie Dale, founder of Dense Breasts Canada, previously told Global News.
She also said the type of information varies — some provinces use older methods to measure and categorize breast density.
“Other provinces are using outdated methods, and many provinces are using methods that don’t include all four categories of breast density so they are ignoring the huge population of women with dense breasts,” Dale said.
Dense Breasts Canada has a list of what different provinces are doing on its website.
For Gordon, Brenda’s experience is all too common, and it represents a major flaw in the approach to breast cancer screening taken by most provinces in Canada.
She believes women should be made aware of their breast density — and what it could mean for their breast cancer risk and screenings — as soon as possible.
— With files from Dani-Elle Dubé and Rebecca Joseph