'Not good enough': Dense breasts halting life-saving cancer diagnoses

High breast density makes cancer harder to see on a mammogram, but it's not always reported to patients Wed 29 Jul 2026 at 6:52am When Kate Clark's breast started leaking fluid, which she says was the colour of Fanta, she knew there was something wrong with her body. She booked in for a mammogram and ultrasound in Canberra, and although both those tests came back negative for breast cancer, she felt she knew her body better. Looking for answers, she went to a specialist, who sent her for an MRI. "I'd had a mammogram and an ultrasound, and both had come back clear,"Ms Clark said. "[But] because of my leaking nipple, I didn't want to just leave it there." And her suspicion was vindicated when the MRI of her breasts "lit up like a Christmas tree", she said. Then, in July 2024, she received the diagnosis that she feared: she had breast cancer. And by that time, it was found that the cancer had spread to her lymph nodes. Because of Ms Clark's dense breasts, the original scans had come back without any signs that something was amiss. "Had I not pursued it further, I could be in a much worse place now and perhaps not even be here,"she said. She is not alone. Dense breasts a breast cancer risk factor High breast density makes breast cancer harder to detect through routine mammograms and is a risk factor for developing breast cancer. Breast density refers to the amount of fibrous and glandular tissue versus the amount of fatty tissue, and around 40 per cent of women in Australia fall into the category. BreastScreen Australia, the national screening program funded by federal and state governments, provides free mammograms but previously had a policy of not recording or reporting patients' breast density. In November 2024, BreastScreen Australia updated its national position to recommend that everyone screened be informed in writing of their breast density, and to encourage patients to have further discussions with their GP about additional screening options. But despite the policy change, only BreastScreen services in New South Wales, Victoria, South Australia and Western Australia measure and report breast density. Vicki Durston, the director of policy at Breast Cancer Network Australia, believes it is vitally important for people to be aware of their breast density. She said that, despite the national position, some states and territories had been slow to implement measures to assess breast density status. "We know that breast density is a risk factor for breast cancer, and we certainly know that approximately 40 per cent of women are at risk of high breast density," she said. "So it's vitally important that women are notified of their status in order to know their risk." In the ACT, despite a commitment to the implementation a year ago, its local chapter of BreastScreen Australia, Breast Screen ACT, does not record breast density. Policy recommending that breast density be reported also covers non-government-run imaging services, such as the ones Ms Clark used. "This was a national position statement put out in 2024, and yet in the ACT and a number of other states, 20 months on, we are still waiting to see the prioritisation of this implementation," Ms Durston said. 'I burst into tears' Unfortunately for Ms Clark, the medical misdiagnoses did not stop at her first mammogram, which failed to show up cancer, or at the ultrasound that followed, but also at her first yearly check-up, while recovering from cancer. She was on holiday with her family when she was emailed the results of another test. "It said suspicious abnormalities found," she said. "I read that, and straight away I burst into tears and went through [the results] with my husband. I couldn't quite believe it." After waiting for the Canberra imaging clinic to open, she was told the clinic had made a typo, and her scan was actually clear. "Sure enough, they came back to me and said … it should have said no … and they amended the report," she said. Ms Clark wants to use her experiences to warn other women of the potential dangers of dense breasts, and the possibilities of unreliable medical imaging. She said she was disappointed to hear the ACT government had still yet to implement dense breast testing. "I feel that it's not good enough … I think they are letting all of us women down by not implementing it," she said. "Should they decide to implement it, it would be life-changing for so many." The ACT government said in a statement that assistive technology to support breast density reporting would be available in the first half of next year. A Canberra Health Services spokesperson said plans to introduce breast density reporting following mammograms were in progress; however, they required significant technical upgrades. "BreastScreen ACT is committed to introducing these changes responsibly and sustainably," the spokesperson said.