Her dense breast tissue hid cancer for years. Now she's warning others
In 2014, Michelle Di Tomaso was diagnosed with advanced breast cancer. It came as a shock to her because she had undergone four clear mammograms.
She was devastated to learn that the tumour in her left breast had been growing for two to three years.
She believes she might have caught it earlier if she knew one thing: she has dense breasts.
But Di Tomaso didn't discover that until after undergoing an ultrasound and a biopsy.
"It was a camouflage effect, and they missed it. I said, 'They missed it for three f–king years?' And [the medical oncologist]'s like, 'It happens,'" Di Tomaso recalled to White Coat, Black Art's Dr. Brian Goldman.
Following the discovery, she underwent rounds of chemotherapy and radiation, a double mastectomy and a raft of complications.
Dense breast tissue can obscure cancer in a mammogram image. (Submitted by Dense Breasts Canada)
Breast density has been known in the medical community for decades, but it's still a relatively unknown issue to family doctors and patients, in part because physicians aren't instructed to tell their patients about it.
While fatty tissue appears as dark grey in a mammogram, dense tissue shows up as mostly white — just like cancers.
In 2016, Di Tomaso co-founded Dense Breasts Canada, a non-profit group which raises awareness about breast density and lobbies to make it easier for patients to find out if they have dense breasts.
"I want a woman to be told her breast density when she has a mammogram … If that woman has dense breasts, I want her to have an ultrasound," she said.
Nearly half of U.S. women have dense breast tissue
Despite the name, dense breasts don't feel any different to the touch. Only a mammogram can identify whether someone's breast tissue is denser than average.
It's like somebody having high blood pressure and not telling them. No family doctor would do that.– Dr. Paula Gordon
Dr. Paula Gordon, Dense Breasts Canada's medical adviser, says she often sees women with dense breasts who have had their cancer missed by a mammogram.
"This is where the anger comes from," she said. "They were never told they had dense tissue, and so they didn't realize there was this huge difference in the sensitivity of mammography depending on how dense the breast tissue is."
Gordon, who is the medical director of the Sadie Diamond Breast Program at B.C. Women's Hospital, added that cancer is "four to six times more common" in women with the highest breast tissue density, but researchers don't know why.
In 1986, the BC Cancer Agency became the first provincial agency to do screening mammograms. From the very beginning, radiologists were asked to indicate on each mammogram if the woman had dense breasts and so they did.
Cinda Lambert on discovering that her dense breasts made cancer detection difficult on mammograms 1:35
But there wasn't a directive to tell patients.
"It's like somebody having high blood pressure and not telling them. No family doctor would do that," Gordon said.
"When I raised it at a committee and said, 'Why aren't we telling them?' they said, 'We don't want to make women anxious.'"
I will take that little bit of anxiety to find out it's OK, than not knowing and then being told I have cancer.– Michelle Di Tomaso
Di Tomaso was "very insulted" when she first heard that reasoning.
"I will take that little bit of anxiety to find out it's OK, than not knowing and then being told I have cancer — just because you guys don't want to tell us. Because of 'anxiety.'"
Gordon wants women to start going for mammograms closer to the age of 40, which she calls "the ideal age to start screening."
That way women can find out sooner whether they have dense breasts. If they do, they can be screened with an alternative method, such as an ultrasound or MRI to check for potential cancers.
Currently, the Canadian Task Force on Preventive Health Care recommends women have a mammogram every two years starting at age 50.
Updating guidelines for patients
Quebec is the only province that requires a woman's breast density information be given to her family doctor.
In other provinces, doctors might be given the info from a mammogram report, but they aren't required to inform patients.
Dr. Paula Gordon, left, shows Cinda Lambert her mammogram and ultrasound results. (Brian Goldman/CBC)