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BCNA urges young women outside national screening guidelines to remain vigilant about fast-growing breast cancer frequently missed or misdiagnosed

Breast Cancer Network Australia

March 2, 2026 – Breast Cancer Network Australia (BCNA) is highlighting the critical need for early detection of Triple Negative Breast Cancer (TNBC) ahead of Awareness Day on Tuesday March 3, warning that this fast-growing subtype of cancer is frequently missed or misdiagnosed in younger Australian women who sit outside the national screening program.

With high profile journalist Cassandra Thorburn recently sharing her diagnosis of Triple Negative Breast Cancer (TNBC0, the spotlight is on this subtype of breast cancer which accounts for around 15 per cent of early breast cancer cases. While TNBC can affect women of any age, younger women are more likely to experience delays in diagnosis because they are not part of the routine BreastScreen Australia program. Additionally, dense breast tissue in younger women can make imaging more challenging.

Unlike other breast cancers, TNBC lacks the three receptors (oestrogen, progesterone, and HER2) used to guide targeted treatments like hormone therapy. Because triple-negative breast cancers tend to be faster-growing than other types of breast cancer, early detection is absolutely critical. In younger Australians, however, that’s not always straightforward.

A Race Against Time for Younger Australians
Melbourne mum Elise Rimington from Surrey Hills had just celebrated her 39th birthday and was enjoying a busy life juggling work and family, with two energetic toddlers at home. The last thing she expected was to be diagnosed with Triple Negative Breast Cancer.

When she noticed a small hard lump in her left breast, she took herself to the doctor to get it checked. She was initially reassured that it was probably a cyst, but was sent for a mammogram and ultrasound to rule out anything more sinister.

"The scans dismissed the lump as probably old mastitis or possible fibroadenoma. I was told to repeat the scan in three to six months,” Elise says. It was also painful, and Elise was told 'breast cancer isn't normally painful’. “But the pain was getting worse and the lump was changing shape - I knew something was wrong.”

Two weeks later, after reading  Breast Cancer Network Australia’s website, Elise insisted on further examination and screening to investigate the changes in the lump. “I was shocked by the results - the lump had almost doubled in size. I was rocked by the words ‘you have cancer’. I now know that if I had waited a few months for follow up scans, I might not be here right now.”

Elise was diagnosed with TNBC, presenting as a Grade 3 cancerous tumor with a KI-67 score higher than 95 per cent and endured six months of strong chemotherapy, 15 rounds of radiotherapy and a lumpectomy.

The young mum has since been given the all-clear. But the risk of triple negative breast cancer coming back or spreading in the first 5 years is higher than some other types of breast cancer. “Recurrence is always planted in the back of my mind, but I am grateful to be here to implore women to trust their instincts and advocate for their own health. Visit the BCNA website or call the BCNA Helpline, keep asking questions, educate yourself, and keep pushing until you get the answers you need.”

Elise also credits the BCNA support networks and online forums for helping her navigate her treatment phase and the aftermath, which itself can be a challenging time. “If I could change one thing in the health response to breast cancer, it would be ensuring access to the best diagnostic technology for early scans. This could improve the prognosis for any young women who find themselves in my shoes in the future.”  

Young Women Outside the National Screening Guidelines
Emphasising that this subtype requires a different diagnostic approach from both patients and GPs due to its fast-growing nature, BCNA also notes that dense breast tissue in younger women can lead to "clear" scans, providing a false sense of security.

“Because women under 40 fall outside the routine BreastScreen Australia age bracket, this cancer is often only detected in this age group once symptoms appear,” says Vicki Durston, BCNA Director of Policy, Advocacy and Social Services.

“Statistically, the vast majority of breast changes are not cancer; however, with a subtype as fast-growing as TNBC, we cannot afford to wait. It is not uncommon for a triple-negative lump to change noticeably in just a matter of weeks. This makes it vital that both younger women and their GPs act immediately on any new or persistent changes, even if initial imaging hasn't flagged a concern.”

This was precisely the challenge faced by Elise, who had to navigate a difficult start to her diagnostic journey.

“Thankfully my cancer was surface level and I could feel it. Had it been deeper, the outcome could have been very different," Elise says. “I had to advocate for myself and push hard for further screening. After that initial struggle, I was fortunate to be placed into the care of an amazing medical team who moved quickly.”

This TNBC Awareness Day, BCNA encourages all young women to call the BCNA Helpline at 1800 500 258 with any questions or concerns and visit our TNBC and self-check educational resources at bcna.org.au.

IMAGES AVAILABLE HERE 

For further commentary and select interviews, contact Steve Milton at 0423584423 or [email protected].

Note to Editors: Cassandra Thorburn's diagnosis is Triple Negative Occult Breast Cancer. Occult breast cancer presents as disease usually in the axillary (armpit) lymph nodes, and other locations, despite the absence of an identifiable tumour in the breast.

Media Contact:
Steve Milton, Comms, BCNA
0423 584 423 | [email protected]

Contact details:

Steve Milton, Comms, BCNA
0423 584 423 | [email protected]