Breast cancer – can prevention become more personalised?

Sowmiya Moorthie

6 November 2017

Breast cancer is the most common cancer to affect women and is recognised as a leading cause of mortality across the world. It also affects a small proportion of men. Whilst complete prevention of the disease is not currently possible, we can reduce the chances of developing it.

The standard approaches taken include raising awareness, educating people on their risk, encouraging healthy lifestyle choices and offering screening to try to identify the disease at an early stage, when it is much more amenable to treatment. But, given that we know the development of breast cancer is influenced by many different factors, and these risk factors vary between different people, could we do more to prevent this serious disease?  The PHG Foundation is examining this issue as part of a European Commission (EC) funded research project, Breast Cancer Stratification (B-CAST).

Is it time for risk adjusted screening?

Breast cancer screening can be a controversial subject. On the one hand, identification of the disease at an early stage can improve treatment outcomes and prevent deaths. On the other hand, screening can also identify growths that would not progress to symptomatic disease, which can result in unnecessary treatment. Questions are also raised about whether all women should follow the same screening pathway, regardless of their risk. In the UK, all women between the ages of 50-70 are invited to participate in routine screening mammography on a three yearly basis. No other risk factors besides age (and sex) are taken into consideration, and the identification of women who are at high risk of breast cancer as a result of family history, which may be indicative of an underlying genetic predisposition (e.g. BRCA1/2 carriers), depends upon them presenting with a concern to their GP.

We have known for some time that genetic information is important in determining the risk of developing breast cancer. The PHG Foundation has previously concluded that including genetic data alongside age could improve the accuracy of risk prediction and allow more targeted screening. Studies are underway in several countries to examine how we can offer more tailored screening, taking into consideration a greater number of risk factors including family history, lifestyle behaviours (alcohol, obesity) and genetics. These include the PROCAS study in the UK, PRISMA study in the Netherlands and the WISDOM study in the United States.

We have known for some time that genetic information is important in determining the risk of developing breast cancer. The PHG Foundation has previously concluded that including genetic data alongside age could improve the accuracy of risk prediction and allow more targeted screening.

As part of the PROCAS study, researchers have developed a genetic test to assess small variations in a number of genes (single nucleotides polymorphisms, or SNPs), that collectively may increase the risk of breast cancer, and that might be present in women with family history of breast cancer but who do not carry a high-risk BRCA1/2 gene mutation. This test could help to provide women with a more accurate measure of their risk, and allow them to make better –informed decisions about preventative procedures such as mastectomy.

Moving research into policy and practice

The number of cases of breast cancer is continuing to rise throughout the world, with a huge impact on women and their families. Given the pace of technological development and accumulating scientific knowledge, can we create a seamless prevention pathway, providing women with more individualised information on their risk and ways to reduce it? If so, will this have a positive  impact on disease prevention?

We have started to investigate this with analyses of current approaches to breast cancer prevention, and the policy discourse around personalised breast cancer prevention. The results of our research will be published at the end of 2017. A better understanding of current practice and policy enables assessment of the potential impact of new knowledge, and how best to integrate it into existing care pathways. Ultimately, integrating new scientific intelligence and technological advances in breast cancer prevention requires a collective vision and concerted effort from patients, health professionals, researchers and policy makers.