Opaque diagnosis Dense breast tissue raises cancer risk, complicates screening Silenced Symptoms
By: AV Kitching Posted: 5:56 PM CDT Monday, Sep. 30, 2024 Last Modified: 11:52 AM CDT Tuesday, Oct. 1, 2024 Updates

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This article was published 30/09/2024 (342 days ago), so information in it may no longer be current.

Despite doing everything by the book, kindergarten teacher Heather Brister, 48, feels she has been failed by Manitoba’s policies for breast-cancer screening.

The mother of three from Neepawa first felt a small lump “the size of a pea” on her right breast in May 2021.

She was 44 at the time and, under the province’s current health policy, was not eligible for a screening mammogram.

Brister consulted with her family doctor, who immediately booked her in for a diagnostic mammogram.

“The mammographer said, ‘You’re really young, so I’m sure this is nothing.’ She did the mammogram and nothing showed on the screen.

“She said, ‘It looks great; you’re young and it could be hormonal changes,’ and she sent me home,” Brister recalls.

Brister was relieved.

Even though there was no family history of breast cancer, finding the lump was stressful and she was pleased to put it behind her.

Eight months later, in January 2022, on recess duty in the playground, her arm brushed against the side of her breast and she felt the lump through her winter jacket.

Later that day, she carried out a self-examination and realized the lump was bigger.

“The world actually slowed for a minute. I just knew it was bad. I went back to my same doctor and he said, ‘Oh, Heather, I am sorry. This is probably breast cancer.’ He sent me for a mammogram immediately.”

However, her lump, which had grown to 10 centimetres, was still not being picked up by mammogram; she was once again reassured that there was nothing to worry about.

Owing to the increased size of the lump, Brister was sent for an ultrasound and a biopsy — and yet another mammogram — in an attempt to identify it, this time with a clip in the tumour to track it.

“Earlier that day, when I had that first mammogram, the mammographer said to me, ‘I am not seeing anything sinister. You’re young; I am not seeing anything, so it’s all good,’” Brister recalls.

“When I told her I just had a biopsy and an ultrasound, she did my mammogram and she said, ‘Oh, I can see where they put the clip, but I can’t see anything else here. I think you’re fine.’ She tried and tried and tried and still she could not see anything.”

Six days later, on Jan. 20, 2022, Brister was diagnosed with triple negative advanced invasive ductal carcinoma.

The cancer had spread to her lymph nodes; the tumour, when they finally did find it, was almost 11 cms.

She was a Stage 3C breast-cancer patient.

Unbeknownst to her, Brister had dense breasts. Her tumour had remained undetected in the multiple mammograms owing to her breast density.

Breast density is divided into four categories: A, B, C and D. Those categories reflect the proportion of dense tissue relative to fat.

All women have fat and dense breast tissue in their breasts, but the amount varies. Only those in category C and D are classified as having dense breasts.

While mammography works exceptionally well in spotting cancer in women with fatty breasts, it alone is not enough for women who have dense breasts.

On a mammogram, a cancerous tumour and dense breast tissue both present as white, creating a masking effect in women with dense breasts.

At no point during any of her mammograms was Brister told she had dense breasts. She was not made aware that her breast density would make it extremely difficult for her tumour to be seen, nor that women with dense breasts have a higher risk of breast cancer than those with fatty breasts.

To this day, Brister does not know what category her breast density falls under.

It was only during her first meeting with her oncologist, when she asked him why her aggressive form of cancer had not been spotted with mammograms, that she learned about dense breasts.

“Before my oncologist told me, I had never heard that term. He said, ‘Oh, a mammogram is just a screening. It quite often doesn’t show things,’” she says. “That’s when he explained dense breasts to me. He said mammograms don’t work for me because I have a high breast density.

“I wish somebody had said this to me before. My oncologist referring to a mammogram as just a screening tool… people need to hear that. And people need to ask what their breast density is when they have mammograms and, if they have a level C or D breast density, they need to request supplemental screening,” she says.

While Brister’s experience may seem unusual, it’s far more common than it needs to be.

Potentially life-saving information is being withheld from women, says Jennie Dale, co-founder of Dense Breasts Canada, a non-profit organization committed to raising awareness and advocating for optimal breast-cancer screening.

“I have heard so many stories like Heather’s,” Dale says. “Women are having their mammograms and thinking that they don’t have cancer when they actually do. There are hundreds of stories of women who don’t know about breast density until they get breast cancer, and it is a later-stage diagnosis and then they are upset. Because no one told them, they didn’t inform them.”

In category D density, mammograms will miss about 40 per cent of breast cancers; in category C, about 25 per cent will be missed. Mammograms alone are not enough for women with dense breasts.

As a result of patient advocacy, women in Manitoba are now told if they have dense breasts in their mammogram result letters, but are then unable to access the essential screening they need.

“The letter gets mailed, but no other action is taken on it. That’s where the travesty is,” Dale says. “Women are just told they have category C or D dense breasts, but are not given the implications of that and are not advised to seek supplemental screening.”

Dense Breasts Canada’s medical adviser Dr. Paula Gordon, a clinical professor in the department of radiology at the University of British Columbia, says that while mammograms are considered the gold standard when it comes to detecting breast cancers, around 40 per cent of cancers are missed in the women with the densest category-D breast tissue.

Her research in 1995 showing ultrasounds can detect cancers missed on mammograms has led to conversations about how women with dense breasts are screened.

“Randomized controlled trials conducted between the 1960s to the 1980s have proved conclusively that doing mammograms saves lives,” she says. “And we have modern research that shows that we can reduce death by about 50 per cent if women have mammograms compared to women who don’t. But 50 per cent isn’t good enough.”

Gordon says Manitoba should offer additional tests, such as ultrasound and MRI, to identify cancers at an earlier stage.

“There are a lot of women dying from breast cancer. Substantial numbers are overlooked in category C. In B.C. we have been auditing outcomes in our practice — we do the most screening in ultrasound in B.C. — and we are finding that 84 per cent of cancers that were found on ultrasound, the ones that were missed on mammograms, are in women with category-C dense breasts.”

In B.C., women in category C and D, regardless of family history, have been offered supplementary screening since 2019.

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Jennifer Borgfjord, 54, of Breast Screening Advocates Manitoba was invited to her first screening mammogram in September 2020 at the age of 50.

When the results came back with an all-clear, Borgfjord wasn’t particularly surprised, as there was no genetic predisposition for breast cancer in her family.

Two years later, it was time for another mammogram. She dutifully made her way to the screening clinic and again, the results came back “normal.”

A month later, in April 2023, while getting ready to go to school, the teacher felt a small lump on her left breast.

Concerned, she spoke to her husband about it, deciding to wait a week before seeking advice from her family doctor.

“I was wrestling with my inner self,” she says. “After all, I had just come back from a mammogram and had an all-clear. I felt silly going to the doctor, but I wanted to be safe. I am lucky I took that lump seriously, as it turned out to be cancerous.”

Today, Borgfjord, who was diagnosed with Invasive Ductal Carcinoma Stage 2A , has to take daily medication, as well as supplements. She will have to attend annual diagnostic mammograms for the rest of her life.

While she has been declared NED (No Evidence of Disease), and considers herself to be in good shape, side effects of her lumpectomy include lifelong lymphedema — swelling caused by a compromised lymphatic system — which may require her to wear a fibrosis pad and compression sleeve for the rest of her life.

Not only did both of Borgfjord’s screening mammograms miss her cancerous tumour, her fibroadenoma — a benign form of tumour — had also been overlooked, which impacted her treatment timeline.

Both lumps had been masked by her dense breasts.

“Both my letters included information about my breast-tissue density and my second letter identified me as having category-C dense breasts, which it said can increase the risk of cancer.”

The leaflet accompanying the letter, however, unequivocally stated “dense breast tissue is common and normal and does not mean you will develop breast cancer.”

“The literature contradicts itself,” Borgfjord says. “I have category-C dense breasts, which appear white on mammogram imaging. Cancer also appears white on mammogram imaging. I needed supplemental screening — ultrasound and MRI — to find the 2.3-centimetre tumour. But there is no call to action in the letter. They do not offer supplemental screening.”

Borgfjord had initially requested a mammogram in her mid-40s after being told a number of times during clinical breast exams that she had “lumpy” breasts.

She expressed concern about this condition to her family doctor, who told her that according to the Canadian Task Force on Preventive Health Care, she was too young to be screened.

“Being naive, I thought, ‘Oh, good, nothing to worry about.’ I believed I was not a risk because I had no family history. I blindly trusted my doctor and no requisition was made. If I could redo that moment, I would insist on one.

“Had I had a screening in my 40s, radiologists would have had multiple films to look at over time. My pathology showed DCIS, Ductal Carcinoma In Situ, which means something obviously was percolating there long before I felt my lump… so they would have had that, they would have had those multiple mammograms.”

Before her dense-breast classification Borgfjord had not heard of the term. During her radiation treatment, she started to conduct research about dense breasts, and came across the Dense Breasts Canada website. Since November 2023, she has been advocating for change in Manitoba’s breast-screening policies.

She wants women over 40 with C or D dense breasts to be offered a screening ultrasound; but first Manitoba has to offer all women aged 40-plus the chance to self-refer for a mammogram so they know their breast density. Last week, the provincial government announced plans to increase breast cancer screening and lower the age for self-referrals. (See sidebar)

“I am one of the fortunate ones, having caught my breast cancer at an early stage. I do often think about how different things would have been had I relied solely on routine mammograms, unaware that a tumour would have been growing undetected, potentially spreading to my lymph nodes and beyond,” she says.

“This summer, I had the joy of walking my son down the aisle at his wedding and celebrating with my friends and family. Watching my children embark on their careers is something I’m not taking for granted.”

Borgfjord will continue educating others through Know Your Lemons, a breast-health self-examination app, and advocating with Dense Breasts Canada and Breast Screening Advocates Manitoba.

“I am grateful for the treatment I received, and I want to be a voice for how the breast-screening system and surveillance should be improved.”

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In North America, 40 per cent of women over the age of 40 have dense breasts. In Manitoba, women aged 40-49 cannot currently self-refer for a screening mammogram. Without a mammogram, a woman cannot know her breast density.

Not screening women in their 40s and not offering supplemental screening places women at greater risk of a delayed and advanced diagnosis.

“I try not to live in the ‘what if,’ but I don’t want somebody else to go through this.”–Heather Brister

Manitobans with dense breasts and those in their 40s are at a disadvantage for finding breast cancer early, compared to women in other provinces.

“Right now, your chance of detecting breast cancer depends on where you live. Manitoba needs to get its act together and really take action if it’s going to save lives,” Jennie Dale of Dense Breasts Canada says.

“All women should be told their breast density and the implications, meaning you are at increased risk at getting breast cancer and an increased risk of having cancer missed on your mammogram.”

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Had Heather Brister been made aware of her breast density, it would have saved her months of “torture.” She says it is hard not to feel failed by the health system.

“I try not to live in the ‘what if,’ but I don’t want somebody else to go through this. A mastectomy is no joke; it’s hard. If they had caught it at Stage 1, I wouldn’t have gone through months of hell … Watching me go through that changed our family.

“When I think back to the first mammogram I had, eight months prior to my diagnosis… if I had been educated in breast density or sent a report that stated I had dense breasts, I would have been able to advocate for myself. Being told I was ‘too young’ gave me false hope, based on nothing but someone’s misguided opinion.

Brister can’t help dwelling on the fact that had she been referred by the radiologist for supplemental screening, perhaps her cancer could have been caught at Stage 1, with less radical treatment and less risk for lifelong side effects.

“I would like more information out there that is readily available for women of all ages,” she says.

“Mammograms at the age of 50 are too late for so many people, so that age of self-referral for mammograms needs to be 40. And if you have dense breasts, there needs to be supplemental screening. There has to be.

“We have to catch it sooner.”

av.kitching@freepress.mb.ca