Cancer
Breast density— the cancer risk factor millions of women may not know about
Data suggests millions of women in the UK aren’t being told their breast density, despite it being a risk factor for cancer.
New research, published during Breast Cancer Awareness Month, has revealed a stark lack of awareness around breast density among UK women.
Just under half (40 per cent) of women over the age of 40 have dense breasts —breasts with more fibrous or glandular tissue and less fat—with Asian women more likely to have dense breasts than women of other ethnicities.
While it is normal for breast density to vary from woman to woman, studies have shown that those with extremely dense breasts are four to six times more likely to get breast cancer than a woman with fatty breast density.
It is also understood that having dense breasts makes it harder to detect breast cancer through mammography, the standard screening method worldwide.
Breast cancer is the most common form of cancer in women globally, affecting around two million women every year, with over 56,000 new cases in the UK alone. Early diagnosis is key, with over 90 per cent of women surviving for five years or more, when it is diagnosed in the early stages.
But the new research, conducted by Bristol-based health tech company, Micrima, found that 86% of women in the UK (around 23.8 million) don’t know their breast density. In fact, they are six times more likely to know their childhood phone number.
The survey, conducted in partnership with Opinium, also revealed that two thirds (67 per cent) of women are unaware that having dense breasts makes it harder to screen for breast cancer using standard methods, with one in 20 (five per cent ) thinking it makes it easier, and one in six (16 per cent) believing it makes no difference.
Based on this, Micrima estimates that as many as four million women over the age of 40 in the UK have dense breasts and don’t know they are at greater risk of developing cancer.
“I had no idea I had dense breasts”
Clare Cowhig was one of those women. She was diagnosed with invasive ductal cancer in both breasts in 2018 at the age of 50.
Despite having a clear mammogram nine months previous, she booked a private ultrasound after becoming concerned about an unusual area on her breast.
Clare was told by the sonographer that she had “the densest breasts they had ever seen” and was questioned about why she hadn’t been having MRIs due to the reduced sensitivity of mammography to find tumours in dense breasts.
“Despite my significant family history of breast cancer, and having had mammograms annually since I was 41, I had no idea I had dense breasts, or why that was significant,” says Clare.
Clare believes her cancer could have been detected sooner.
“Unfortunately, after further investigation, it was confirmed I had an invasive ductal cancer in each breast. I had highly dense breasts and these tumours never showed up on my mammograms. One tumour was stage-three and over five centimetres, the other was stage two and two centimetres. I had further areas of ‘in-situ’ disease in both.”
Following the sonographer’s comments, Clare requested her hospital records and discovered that her dense breast tissue had been noted after each of her annual mammograms, yet the information was never shared with her. Now she believes that had she been aware of this, the cancer may have been detected sooner.
“If I had been told about my dense breasts, I would have sought additional screening,” she adds.
“I believe my tumours could have been found at a smaller and less advanced stage and I wouldn’t have had to endure such extensive treatment, including a double mastectomy.”
Lack of awareness is “deeply concerning”
Adrian Waller, CEO of Micrima, which has developed a specialised scanning technology to analyse breast tissue without the need for a hospital visit, described the lack of awareness in the UK as “deeply concerning”.
“Breast density is known within the medical community, but it is not part of the standard pathway for either breast cancer screening or symptomatic service,” Waller explains.
“Our medical services have not had the resources or capacity to provide the supplemental testing required to improve detection rates for women with dense breasts.
“This is compounded as currently the only way of measuring breast density is from a woman’s initial mammogram. Until the development of Micrima’s RF based device Mi~Scan®, there hasn’t been the technology available to measure breast density simply and effectively.”
Mi~Scan®, which has shown “strong initial results” in the clinical trial phase, is designed to analyse breast tissue quickly and painlessly— without ionising radiation— to help clinicians identify the right diagnostic test for cancer detection.
“We want women to be empowered with the knowledge of their breast density so they can be in greater control of their breast health,” continues Waller.
“We also want to support the medical and radiology communities to explore and build in density measurement within the breast screening pathway, enabling more efficient delivery of personalised diagnostic pathways.”
CEO of Micrima, Adrian Waller, is calling for government regulation.
Calls for government regulation
Awareness of breast density is thought to be higher in the US, where a new FDA ruling – introduced earlier this month – requires all mammography reports and results sent to patients to include an assessment of breast density.
Waller and others are also calling for similar regulation in the UK.
“We would like to see the Government regulate around women being told their breast density when they receive results from a mammogram – much like has happened in the States,” he adds.
“Ultimately, we would like women to have their breast density measured routinely at a community level, in order for GPs or Community Diagnostic Centres to create an individualised risk profile for each of their patients.”
“Lifting the lid” on breast density
Leslie Ferris Yerger, founder and CEO of the charity My Density Matters, was diagnosed with Stage IV breast cancer in 2017, just two months after a routine mammogram and ultrasound gave her the ‘ all clear’.
“Hidden by dense breast tissue, my cancer was left to grow and spread,” she says.
“Breast density is so important and Micrima’s research spotlights that we must do more to lift the lid on breast density and let women know why it matters. We need to empower women with knowledge so they can take ownership of their breast health. When we catch cancer sooner, the chances of survival are greater.”
The FDA has delayed approval of camizestrant while it reviews new analyses submitted by AstraZeneca after advisers voted against the breast cancer drug.
The US regulator had been considering whether to approve the oral treatment after a phase 3 switching study in a specific group of breast cancer patients.
Camizestrant is an oral SERD, or selective oestrogen receptor degrader. These drugs are designed to block and break down oestrogen receptors that can help some breast cancers grow.
AstraZeneca filed for approval based on the phase 3 Serena-6 trial, which tested a treatment-switching approach.
Patients in the study received an aromatase inhibitor and a CDK4/6 inhibitor. Aromatase inhibitors lower oestrogen levels, while CDK4/6 inhibitors are targeted cancer drugs that help slow cancer cell growth.
After detecting an ESR1 mutation, investigators switched the aromatase inhibitor to camizestrant.
An ESR1 mutation is a change in a gene linked to the oestrogen receptor. It can make some breast cancers less responsive to standard hormone treatments.
AstraZeneca said switching to camizestrant was linked to a 56 per cent increase in progression-free survival.
Progression-free survival measures how long a patient lives without their disease getting worse.
However, the FDA raised questions about the study design.
An FDA advisory committee later voted six to three that AstraZeneca had failed to show camizestrant provides a clinically meaningful benefit.
The vote was a setback for the company’s hopes of approval, although the FDA can go against advisory committee recommendations.
After the setback, AstraZeneca submitted additional analyses requested by the FDA.
The company said the analyses include data on circulating tumour DNA clearance linked to longer-term efficacy outcomes.
Circulating tumour DNA refers to fragments of genetic material from cancer cells that can be found in the blood.
AstraZeneca is expected to share the data next week at the American Society of Clinical Oncology annual meeting.
The FDA has now delayed its ruling while it reviews the additional information. AstraZeneca did not provide a new decision date.
Three-month delays are typical and, during the second Trump administration, have been common.
After budget cuts reduced its workforce, the FDA delayed rulings on assets including Bayer’s Lynkuet, Biohaven’s troriluzole and Sanofi’s tolebrutinib. The FDA reportedly blamed a “heavy workload and limited resources” for one delay.
The agency has continued to delay rulings this year, with Biogen, Savara and Travere Therapeutics among the companies to say the FDA has extended reviews of their drugs.
Like AstraZeneca, those three companies faced delays after submitting additional information that the agency needed time to review.
If the additional analyses address the regulator’s concerns, AstraZeneca could still secure approval for a drug it has estimated could generate peak sales of more than US$5bn.
Guggenheim Securities analysts recently described the Serena-6 study as “a limited commercial opportunity in our and [AstraZeneca’s] view”.
AstraZeneca is also running two adjuvant studies and a trial in a first-line setting as it seeks to position camizestrant across different stages of breast cancer care.
Adjuvant treatment is given after primary treatment, such as surgery, to reduce the risk of cancer returning. First-line treatment is the first therapy given for a disease.
Roche reported the failure of its rival oral SERD in first-line breast cancer in March, but AstraZeneca executives have argued that their trial designs and drug candidate are different.
Last week, Europe’s Committee for Medicinal Products for Human Use issued a positive opinion on camizestrant.
The drug is expected to be marketed as Etcamah in Europe.
An early PET scan after one cycle of chemotherapy may help predict how aggressive breast cancer responds to treatment, a study suggests.
Research led by The Institute of Cancer Research, London and King’s College London suggests that an early scan taken after one cycle of chemotherapy could help predict how well a patient’s cancer will respond to treatment.
The study focused on patients with triple-negative breast cancer (TNBC), an aggressive form of the disease in which cancer cells lack receptors for the hormones oestrogen and progesterone, as well as the HER2 protein.
Patients with TNBC are usually treated with chemotherapy prior to surgery. While many respond well, residual disease at surgery, typically around six months later, is associated with a significantly poorer prognosis. Identifying people sooner who are unlikely to respond remains a major clinical challenge.
The research explored whether using PET imaging shortly after treatment begins, rather than relying only on MRI scans later in the treatment process, could provide earlier insight into how a patient’s cancer is responding. Twenty-two patients were recruited, with fourteen undergoing FDG-PET scans before treatment and after the first cycle of chemotherapy.
The findings, published in Clinical Cancer Research, showed that changes seen on PET scans after just one cycle of chemotherapy were strongly associated with subsequent response, including whether there was no detectable cancer, known as a complete response, by the end of treatment. Importantly, early PET response showed stronger associations with treatment outcomes than standard mid-treatment MRI scans in this study.
Being able to identify patients who are not responding well at an early stage could allow clinicians to adjust treatment sooner or consider alternative approaches. These findings may also support future strategies to better tailor treatment intensity to individual patients.
The study also compared two types of PET tracers, FDG and FLT, to determine which was most suitable. While both met the study’s technical criteria, FDG-PET was selected for further evaluation due to its better image quality, greater consistency and wider use in clinical practice.
The research also explored how imaging changes after just one cycle of chemotherapy relate to the body’s immune response to treatment. Biopsies taken before and after the first cycle of chemotherapy showed that an increase in immune cells within the tumour was strongly associated with both early PET changes and improved treatment outcomes.
The researchers emphasise that these findings now need to be validated in larger studies. Future work will aim to confirm these results in broader patient groups and explore more accessible imaging approaches, such as ultrasound, alongside PET and MRI.
Sheeba Irshad, professor of cancer immunology at King’s College London and lead of the Breast Cancer Now KCL Research Unit, said:
“In patients who had PET scans both before treatment and after the first cycle, we found that this early scan could predict whether they were likely to achieve a complete response by the end of treatment. These findings highlight the potential of early imaging to guide treatment decisions, and now need to be validated in larger, modern clinical trials.”
Andrew Tutt, professor of breast oncology at The Institute of Cancer Research, London, said:
“Research that helps us determine early who is already benefitting from standard neoadjuvant chemotherapy and who might benefit from clinical trials to find better treatments is vital. This study shows that FDG-PET may have great value in this regard. We hope to be able to design studies that further investigate and validate these findings.”
The study was supported by funding from King’s College London and Guy’s and St Thomas’ NHS Foundation Trust, Breast Cancer Now, Cancer Research UK, and Guy’s and St Thomas’ Charity.
Only one per cent of women can name all five gynaecological cancers, new research suggests, as 21 women in the UK die every day of the diseases.
The report also found that 31 per cent of women have put off or avoided seeking medical advice for gynaecological symptoms.
It also found that 43 per cent of women invited for cervical screening said barriers had put them off attending, while 18 per cent of respondents aged 25 to 34 who had been invited had never attended.
The five main gynaecological cancers are womb, also called uterine, ovarian, cervical, vulval and vaginal cancer.
The Lady Garden Foundation said that, while progress has been made since the UK government’s 2022 Women’s Health Strategy aimed to improve gynaecological cancer care, significant challenges remain.
John Butler, medical director and trustee at the Lady Garden Foundation, said: “The fact that only one per cent of the population can name the diseases that directly affect half of us underscores a significant awareness gap, impacting individuals’ ability to recognise vital signs and symptoms or seek timely medical help.
“Addressing this isn’t just about awareness; it’s a critical public health priority. Our collective efforts are essential to ensure the latest commitments announced by this government translate into tangible change that saves lives.”
The report said key reasons for delaying medical advice included difficulty making appointments, embarrassment and, for cervical screening, fear of pain or previous bad experiences.
Women also reported challenges within healthcare interactions, including feeling “not taken seriously”, “dismissed” or “not believed” when seeking gynaecological advice.
Jenny Halpern Prince, chief executive and charity co-founder, said: “We frequently hear reports of women feeling ‘not taken seriously,’ ‘dismissed,’ or ‘not believed’ when seeking gynaecological advice.
“These experiences highlight crucial areas where we can improve patient support and trust within our healthcare system, ensuring women receive the empathetic and effective care they need.”
The Lady Garden Foundation said it aims to increase awareness of both the charity and the five gynaecological cancers.
It also aims to serve as a primary entry point for reliable, stigma-free information, helping people understand their bodies, recognise symptoms and overcome barriers to accessing care.
Its Silent No More Garden was unveiled at the RHS Chelsea Flower Show 2026. Designed by Darren Hawkes, the garden serves as a national call to action, using five sculptures to spark conversations, break long-standing taboos and encourage open dialogue about symptoms and preventative care.
Butler said: “Continued focus and collaborative action are essential to progress.
“The ongoing commitment from the government, alongside societal efforts to break down taboos surrounding gynaecological health, are crucial.
“The Lady Garden Foundation is dedicated to being a beacon of information and support, empowering women with the knowledge they need. We urge everyone to learn the signs, speak up, and help us save lives.”
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