Experts are urging the Government to ensure women are told about their breast density, a factor linked to an increased risk of breast cancer.
Breast density refers to the proportion of glandular and connective tissue in the breast compared with fatty tissue.
It cannot be determined by looking at or touching the breasts. Breast density can only be assessed through a mammogram or another form of breast imaging.
Women with extremely dense breasts may face up to six times the risk of developing breast cancer. Dense tissue can also make tumours more difficult to identify on mammograms, as both dense tissue and cancerous growths appear white on the images.
Although NHS breast screening services record breast density, most women are not routinely given this information.
Earlier this year, Wales became the first UK nation to let women request their breast density score.
Experts are now calling for women in the rest of the UK to have the same access.
‘Women in the US have been receiving information about their breast density for some time,’ says Dr Liz O’Riordan, a former breast cancer surgeon who has personally experienced the disease three times.
Lisa Hier, 53, from Bridgend, South Wales, was diagnosed with stage three breast cancer last year. She first saw her GP in November 2017 after her left breast began to feel unusually heavy. A mammogram and ultrasound did not show any signs of cancer
‘I went from feeling reassured to facing a serious diagnosis and intensive treatment,’ says Lisa, pictured with her mother Pauline
‘There is no justification for a postcode lottery. Every woman in the UK should be told her breast density.’
About 56,000 women receive a breast cancer diagnosis in Britain each year.
Although nine out of ten patients now survive the disease, breast cancer still causes more than 11,000 deaths annually.
As part of the NHS screening programme, women aged between 50 and 71 are invited to have a mammogram every three years. Screening remains a crucial tool in detecting breast cancer, but it is less effective for women with dense breasts.
A UK study published in The Lancet medical journal last year examined whether two additional imaging techniques could be offered to women in this group.
One option, contrast-enhanced mammography (CEM), involves injecting dye to highlight blood vessels on the scan. The other, abbreviated magnetic resonance imaging (AB-MRI), is a shorter version of a conventional MRI scan.
Researchers concluded that adding either CEM or AB-MRI to existing screening could identify an additional 3,500 cases of breast cancer each year.
Research has also established that women with dense breasts have a greater risk of developing the disease, although the reasons for this link are not yet fully understood.
For approximately one-third of women with moderately dense breasts, the risk may be as much as four times higher. Among those with the densest breast tissue, it can be six times greater. However, having dense breasts does not mean a woman has cancer or will necessarily develop it.
The UK National Screening Committee (UKNSC), the independent body that advises governments, currently does not recommend routinely informing women about their breast density or providing additional screening solely on that basis. It is, however, reviewing the available evidence.
‘At present, women are screened as though they all have the same level of risk, but our risks are not identical,’ says Professor Zoe Winters, a consultant breast cancer surgeon and founder of the private clinic London Breast Health. ‘Breast density is an independent risk factor.’
Specialists say that receiving this information could also prompt women to make changes that may help lower their risk.
‘Knowing you have dense breasts can provide extra motivation to take steps that may reduce your risk, such as exercising, drinking less alcohol and maintaining a healthy weight,’ says Dr O’Riordan.
Lisa Hier, a 53-year-old from Bridgend, South Wales, believes she might have approached her own health differently if she had known about her breast density before her stage three diagnosis last year.
She first went to her GP in November 2017 when her left breast started to feel unusually heavy. Both a mammogram and an ultrasound failed to detect cancer.
In May 2023, Lisa underwent routine breast screening and was again told that no problems had been found.
‘Women in the US have been receiving information about their breast density for some time,’ says Dr Liz O’Riordan, a former breast cancer surgeon who has experienced breast cancer three times. She is pictured before a cancer operation
Lisa Hier during treatment for breast cancer. She has undergone a mastectomy, chemotherapy, radiotherapy and lymph node surgery
The following year, however, Lisa noticed changes in her breast. Additional scans and a biopsy confirmed that she had advanced breast cancer.
‘It was devastating,’ she says. ‘I went from believing I had been reassured to facing a serious diagnosis and intensive treatment.’
Since then, Lisa has undergone a mastectomy, chemotherapy, radiotherapy and surgery on her lymph nodes.
‘I truly believe that if I had known my breasts were extremely dense, I would have understood more clearly the limitations of mammograms and could have made an informed decision about having further tests,’ she says.
Cheryl Cruwys, co-founder of the charity Breast Density Matters UK, says: ‘Knowing your breast density can make the difference between an early-stage and late-stage diagnosis. Wales has led the way, and now the rest of the UK needs to follow.’
A Public Health Wales spokesman said: ‘Public Health Wales recognises that breast density is an important issue for some women and that higher density can make breast cancers more difficult to detect on mammograms.
‘Women can request information about the breast density category recorded on their most recent mammogram.’
The Department of Health and Social Care was approached for comment.