Breast Screening in the UK – Breast Density and Impacts on Health


by Cheryl Cruwys

Mammography screening saves lives and is currently the ‘gold standard’ screening test for women in the UK national breast screening programme.  However, it has become apparent that ‘One Size Does Not Fit All’ and ongoing research and studies aim to develop a more tailored, personalised, risk stratified breast screening programme for UK women.

In 2016, Breast Density Matters UK was formed to raise awareness about the implications of dense breast tissue on mammography screening.  The issues are two-fold and are not well known in the UK.  First, dense breast tissue can hide cancers. Following a mammogram, women receive a “results” letter. In the letter, a ‘normal’ notification (no sign of cancer) implies that a woman is cancer free. However, this is not always the case for women with dense breasts, as cancers can be hidden and undetected in dense tissue. These mammography-missed hidden cancers may grow until diagnosed at a later stage when palpable, larger, at a more advanced stage and when less treatable and survivable. The denser the tissue, the more likely it is that a cancer may be missed (see image below).

Cancer on a mammogram of a fatty breast vs a dense breast

The second issue women are unfamiliar with about dense breasts is that they also increase the risk of developing breast cancer. The greater the density of the breasts, the greater the risk.

When a woman has a mammogram her breast density is rated into one of four categories. Breasts that are here (C) heterogeneously dense or (D) extremely dense, are considered “dense breasts.” Dense breasts are normal and common; approximately 40 percent of women at mammography age have dense breasts. In dense breasts, the addition of any screening tool after a mammogram, like ultrasound or MRI, will detect more cancers than mammography alone.  Unfortunately, because cancer is more likely to be missed, women with dense breasts do not benefit as much from mammography as women  with fatty breasts.


    (C) Heterogeneously or (D) Extremely dense breasts are considered ‘dense breasts’. 

In a forward-facing note, UK studies and trials:

  • BRAID (Breast Risk Adaptive Imaging Density) multi-centre study assessing the impact of supplementary imaging in the detection of breast cancer in women participating in the UK national breast screening programme who have dense breast tissue. For women attending a mammogram exam in Cambridge, Cheltenham, Leeds or Manchester, if dense breasts detected, they are invited to participate in the trial and are offered further scans.  Unfortunately, in the meantime, in the rest of the UK, cancers continue to grow undetected in women with dense breasts.
  • The PROCAS studies commenced in 2009. PROCAS 1 focussed on identifying women in the general screening population at increased risk of developing breast cancer. These women could then be offered lifestyle and other interventions to reduce their breast cancer risk, and enhanced screening where appropriate. PROCAS 1 has been published with several outputs.  PROCAS 2 aims to explore the feasibility of implementing PROCAS more widely by using technology-based solutions for assessing risk from questionnaires and breast density.

It may be quite some time before study findings result in breast screening changes for UK women.  Research and studies are long duration to endpoint, data publication and implementation.

News in Europe! Though these studies are ongoing, based on existing research and evidence, there has been some forward motion. In March 2022, the European Society of Breast Imaging (EUSOBI) published important new recommendations for EU breast screening; “EUSOBI thus calls on all providers of mammography screening to share density information with the women being screened. In light of the available evidence, in women aged 50 to 70 years with extremely dense breasts, the EUSOBI now recommends offering screening breast MRI every 2 to 4 years.”  “EUSOBI recommends that, where MRI screening is unavailable for reasons explained, ultrasound in combination with mammography can be used as an alternative.”

Breast screening programmes differ across Europe as do screening protocols recommended if a woman has dense breasts (for details by country, click here.  In some countries, such as Austria and France, it is standard for women with dense breasts to receive supplemental screening, such as ultrasound, after her mammogram.

The push for density “inform” and additional screening has resulted in patient advocacy efforts around the world. The push in the UK and Europe has been led by patient advocate Cheryl Cruwys, of Breast Density Matters UK. She speaks on the topic and, in her role as a member of the ESR Patient Advisory Group, is an invited presenter at the European Congress of Radiology’s upcoming July meeting. Her talks there will focus on improving ‘Communication with Patients’ and ‘What Radiologists Need to Know About Patients’ Expectations’.

Women participating in mammography screening deserve to know the screening and risk implications of their dense breast tissue. Equipped with this important information, women can have informed conversations and make shared decisions about their breast health.

But first, they need to know if their breasts are dense.

Ms. Cruwys is also the European Education Coordinator for medically-sourced website The educational non-profit has developed printable Request for Breast Density forms for women in the UK (England/Northern Ireland/Scotland/Wales and the Republic of Ireland).  Women can complete the form and send it to their screening centres. If they receive a response that ‘breast density is not stored on patients’ files in routine screening’ – they can request a copy of their mammogram images which are stored digitally and can be burnt to disk. In possession of their images, women can consult other healthcare professionals, beit privately, to discuss best screening options.

While progress has been made in raising breast density awareness in the UK, and breast density conversations are beginning to happen, more needs to be done. Understanding the implications of dense breasts and advocating for additional screening if you have them, may mean the difference between an early- or late-stage cancer diagnosis. Until there is a cure, #FindItEarly and detect cancer at the earliest possible stage.


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To contact Cheryl Cruwys:

Twitter @Cheryl_Cruwys   Email:


About Author

Pink Ribbon is the new global charity seeking to make breast cancer-related deaths are a thing of the past. It focuses on political lobbying and campaigning, and the showcase Pink Ribbon awards. Global MD Gerard Dugdill

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