Woman with stage four cancer warns others after clear mammogram missed tumour
A clinical psychologist has been diagnosed with advanced breast cancer and she desperately wants to spread a message about how tissue density can affect screenings.
A Sunshine Coast resident has been diagnosed with stage four breast cancer, despite her routine mammogram the year prior showing “no concerns”.
Peta Stephenson was diagnosed with invasive breast cancer last month and she said it was “completely unexpected”.
“It had already spread to the lymph nodes, and I had no symptoms and felt well at the time,” Ms Stephenson said.
“About three weeks later, after more imaging, I learned it had already metastasized to my spine, ribs, and pelvis.”
Ms Stephenson said the cancer may have been difficult to detect in the prior mammogram due to breast density.
“I’ve since learned that breast density has a major impact on what mammograms can detect, and there are four categories of density — A, B, C and D,” Ms Stephenson said.
“My breast density is category D, which means my breasts contain very little fatty tissue and mostly dense tissue.
“Dense tissue appears white on a 2D mammogram — unfortunately, cancer also appears white.
“So, abnormalities become extremely difficult to see.
Ms Stephenson said because of this it was likely her cancer was not visible in her routine 2D mammogram in 2024.
University of the Sunshine Coast Biomedical Science senior lecturer Lochlan Fennell said breast density could make cancer difficult to detect.
“Dense breasts can make it difficult to detect breast cancers due to the ‘masking’ effect, where dense tissue appears similar to the cancer and thus obscures visualisation of the cancer,” Dr Fennell said.
“Breast density is a key determinant of mammogram sensitivity (dropping from 90 per cent in women with low breast density to below 70 per cent in women with very dense breasts).
“Sensitivity tells us how good a test is at detecting the disease.
“Imagine testing 100 women with breast cancer, if you use a test and it detects 90 then the test has 90 per cent sensitivity.”
Ms Stephenson decided to start a GoFundMe as the diagnosis was “likely to reduce [her] ability to work” as a clinical psychologist.
Her partner was also made redundant in June, making her the sole income earner.
“As the reality of treatment became clearer, it was obvious that I wouldn’t be able to keep working enough to cover my expenses,” Ms Stephenson said.
“The combination of medical expenses, rent, and living costs has created a level of financial pressure that’s been difficult to manage on top of everything else.
“Several people encouraged me to ask for help via GoFundMe, even though it felt uncomfortable to do so I finally agreed — and I’m very grateful I did.”
Ms Stephenson’s GoFundMe has raised more than $20,000 of her $28,000 target.
“I’m honestly overwhelmed,” Ms Stephenson said.
“The generosity shown by friends, colleagues, and even complete strangers has been deeply moving.
“It has eased a huge amount of financial stress and reminded me how compassionate people can be.”
Ms Stephenson wants to inform other people that “breast tissue matters”.
“I want women to know that dense breast tissue matters — it increases the risk of cancer and makes it much harder to detect using standard 2D mammograms,” Ms Stephenson said.
“I wasn’t informed that I had Category D density, and by the time my cancer was found, it had already spread.”
People can donate to the GoFundMe here.
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Originally published as Woman with stage four cancer warns others after clear mammogram missed tumour
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