We all know that ‘prevention is better than cure’ and for breast cancer the message is no different, although the challenge may seem greater.
That challenge is preventing a disease whose incidence is on the rise. A disease that over 50,000 people in the UK are told they have every year. But at Breast Cancer Now, we believe that if we act now, by the year 2050 we’ll be able to prevent 30% of those cases. This means that thousands of women will never have to hear the words “it’s breast cancer.”
What will it take to get us there? Well, we need to work out what causes breast cancer, use that information to find people at risk of getting it and then help them to lower their risk to prevent the disease ever developing. None of these steps are easy, so we’ve asked leading experts working on each of them to share their thoughts on how we’ll do it.
Understanding the causes
“Breast cancer prevention will be a critical component of our strategy to stop people dying from this disease,” says Dr Nick Orr who works in our Research Centre at the Institute of Cancer Research, London. His team is trying to unpick the causes of breast cancer using data from Breast Cancer Now’s Generations Study and Male Breast Cancer Study because, as he explains, “despite recent advances, particularly in the field of genetics, we still have a lot to learn about the causes of breast cancer.”
These causes are complex. We know that lifestyle plays a role as well as genetics, and it’s the interaction between these that researchers including Dr Orr’s team are trying to understand.
A major genetic breakthrough in the mid-90s was finding the BRCA1 and 2 genes, which when faulty, hugely increase someone’s risk of getting breast cancer. But since their discovery it’s become clear that we can’t predict breast cancer based on genetics alone.
“Initial enthusiasm that individual-level risk could be estimated with a reasonable degree of accuracy based on knowledge of a modest number of genetic factors has all but faded,” clarifies Dr Orr, “and emphasis is now being placed on the development of risk models that attempt to partition the population as a whole into discreet groups based on risk.”
Risk models are what scientists and healthcare professionals use to work out someone’s risk of developing a disease based on all the factors that are known to influence that risk. These are already used for people who have an extensive family history of breast cancer but the models need to become a lot more accurate if we want to get better at finding people at risk who don’t necessarily have a family history of the disease.
Improving our picture of risk
So how can we make our risk models more accurate? Professor Tony Howell at the University of Manchester has been working on a UK trial (called PROCAS and led by Professor Gareth Evans) assessing women’s risk when they attend breast screening appointments. “Over the next few years we are more likely to be able to predict risk with much greater accuracy using, for example, breast epithelial cell autoantibodies, as well as epigenetic and protein markers, which are all currently detectable in blood samples. Effective markers may then be added to current risk prediction markers such as family history, endocrine [hormone] factors, mammographic density and risk-associated single nucleotide polymorphisms [small genetic changes].”
The PROCAS trial has been looking at tens of thousands of women attending screening because any measure of risk needs to work on a large scale. Dr Orr clarifies: “We need new measures of risk exposure that can be assessed cost-effectively across the population.” He adds that once we can work out different groups of risk, “we need to develop a range of risk-reducing interventions.”
A “risk-reducing intervention” is essentially any approach that decreases someone’s risk of getting breast cancer. Dr Sacha Howell at the University of Manchester and The Christie NHS Foundation Trust discusses the options currently available:
“Preventing breast cancer through lifestyle measures would also improve women’s health as a whole. Chemoprevention, using drugs to prevent breast cancer, has been partially successful with agents such as tamoxifen, raloxifene and the aromatase inhibitors. However, these drugs can have very troublesome side effects leading to poor uptake and their effect on breast cancer mortality is not clear.”
For women at a very high risk there is also the option of risk-reducing mastectomy but this comes with risks associated with major surgery.
A pill for prevention
Professor Tony Howell explains: “We can already prevent over half of breast cancers using aromatase inhibitors and about 40% by using tamoxifen and raloxifene. A major problem at present is how to prevent breast cancer in the 40-50% of women who do not respond to these drugs.”
To tackle this problem we need alternatives, and Breast Cancer Now is funding Dr Sacha Howell to test an existing drug to see if it can prevent breast cancer.
Dr Sacha Howell says: “Further efforts to explore the causes of breast cancer, coupled with extensive drug screens and novel drug development to identify effective and non-toxic preventative agents will achieve our common goal of reducing both breast cancer incidence and mortality by 2050.”
It’s thought that if everyone could maintain a healthy weight, be more active and drink less alcohol we could prevent up to four out of ten breast cancers.
But it’s hard to change habits. That’s why at Breast Cancer Now we are dedicated to providing clear information on how people’s lifestyle affects their risk, and how they can make a change. We also aim to collaborate with the government and other organisations to make sure people are given as much help as possible to live a healthy life that lowers their risk of breast cancer.
Bringing it all together
It might seem like we have a lot to do to meet our 2050 goal but we believe that with the backing of everyone, including policymakers and researchers, we can get there – and so do the scientists.
Professor Tony Howell thinks we could even beat our target: “By applying these approaches to new drug development, targeting agents precisely to women at risk and promoting lifestyle change, it seems likely that we will prevent more than half of all breast cancers by 2050.”
Find out more about Breast Cancer Now's work on prevention.