Why all women MUST be warned about this breast cancer risk that hides tumours… as experts reveal how it can make you six times more likely to develop the disease

Experts are calling on the Government to provide women with information about their breast density, which is a risk factor for breast cancer.

Breast density describes how much glandular and connective tissue there is in the breast compared with fat.

Women cannot tell by looking at them or feeling them. The only way to assess breast density is through a mammogram or other breast imaging test.

Women with the densest breasts can be up to six times more likely to develop breast cancer. Dense tissue can also make tumours harder to spot on mammograms because both appear white on scans.

NHS screening services already measure breast density, yet most women are not routinely told the result.

Earlier this year, Wales became the first UK nation to allow women to request their breast density score.

Now, experts say that women across the rest of the UK should be able to get this information.

‘In the US, women have been receiving information about their breast density for a while now,’ says Dr Liz O’Riordan, a former breast cancer surgeon who has experienced breast cancer three times herself.

‘There’s no reason to have a postcode lottery and I think every woman in the UK should be given their breast density.’

Around 56,000 women are diagnosed with breast cancer in Britain each year.

While nine in ten now survive, the disease still claims more than 11,000 lives annually.

Under NHS screening, women aged 50 to 71 are invited for a mammogram every three years. Screening is a cornerstone in the fight against the disease, but it falls short for women with dense breasts.

Last year, a UK research paper, published in The Lancet medical journal, looked at offering those patients two additional scanning methods.

The first, contrast-enhanced mammography (CEM), uses dye injected to make blood vessels more visible on the scan. The second, abbreviated magnetic resonance imaging (AB-MRI), offers a quicker alternative to standard MRI.

The research concluded that, by adding either CEM or AB-MRI to current screening practices, an extra 3,500 cancer cases a year could be caught.

Moreover, studies show that women with dense breasts are also at a heightened risk of the disease, although experts do not yet fully understand why.

For the roughly one-third of women with moderately dense breasts, the risk can be up to four times higher. With the densest, the risk can be six-fold. Being told you have dense breasts does not mean you have cancer or will develop it.

At present, the UK National Screening Committee (UKNSC), the independent body that advises governments, does not recommend routinely notifying women of their breast density or offering extra screening based on density. But it is reviewing the evidence.

‘At the moment, we’re all screened as though our risk is the same – but we are all at different risk,’ says Professor Zoe Winters, a consultant breast cancer surgeon and founder of the private clinic London Breast Health. ‘Density is an independent risk factor.’

Experts say that being told you have dense breasts can also encourage lifestyle changes.

‘Knowing that you have dense breasts gives you a bit of impetus to do things to reduce your risk of breast cancer, like exercising, cutting back on alcohol and maintaining a healthy weight,’ says Dr O’Riordan.

One patient who believes she could have benefited from knowing is 53-year-old Lisa Hier from Bridgend, South Wales, who was diagnosed with stage three breast cancer last year.

Lisa first visited her GP in November 2017 after her left breast began to feel unusually heavy. A mammogram and ultrasound showed no cancer.

In May 2023, she attended routine breast screening and was again given the all clear.

But the following year she noticed changes to her breast. Further imaging and a biopsy confirmed advanced breast cancer.

‘It was devastating,’ she says. ‘I went from feeling reassured to facing a serious diagnosis and intensive treatment.’

Lisa has since had a mastectomy, chemotherapy, radiotherapy and lymph node surgery.

‘I genuinely believe that if I had been told about my extremely dense breasts, I would have been more alert to the limitations of mammography and could have made an informed decision about further investigations,’ she says.

Cheryl Cruwys, co-founder of the charity Breast Density Matters UK, says: ‘Understanding breast density can mean the difference between an early or late-stage diagnosis. Wales has taken the first step. Now the rest of the UK must follow.’

A Public Health Wales spokesman said: ‘Public Health Wales recognises that breast density is an important issue for some women, and that higher breast density can make cancers difficult to detect on mammograms.

‘Women can request information about the breast density category from their most recent mammogram.’

The Department of Health and Social Care was approached for comment.