Can I prevent breast cancer?

Can I prevent breast cancer? 

Studies tell us that at least 30% of breast cancers are preventable through simple lifestyle changes, such as improved diet, drinking less alcohol, being active, managing your weight and reducing exposure to harmful chemicals.  

We're here to show you how. 

What does 'preventable' actually mean? 

Scientists around the world have done hundreds of studies on breast cancer risk. But here’s the tricky part: not all studies measure risk in the same way or look at the same groups of people.  

That makes it hard to pin down an exact number of cases that could be prevented. To solve this, researchers use a tool called the Population Attributable Fraction (PAF) a measure endorsed by the World Health Organisation (WHO). Think of it as a way of asking: 

“If we could remove this risk factor, how much of the disease could we prevent in the whole population?” 

In other words, the PAF tells us how big a role each risk factor plays in breast cancer. It combines the relative risk of the exposure with its prevalence in the population to quantify the disease burden attributable to that factor.  

For example, a PAF of 64% for smoking and lung cancer means that 64% of lung cancer cases could be attributed to smoking. 

Why 30%? Why not more? 

We say 'at least 30%' to reflect what we can confidently say based on current evidence: 

• It’s drawn from a wide range of international studies. 
• It accounts for gaps (such as limited data on chemical exposures). 
• It’s a conservative, science-backed minimum, meaning the true impact might be higher once we understand more. 

Why it matters.

Knowing this empowers individuals, communities, and policymakers to act: 

• You: Small changes - like improving diet, being more active, or limiting alcohol - can make a powerful difference. 
• Society: If prevention becomes a shared goal, we can reduce the burden on people and the NHS. 
• Policy: We call for stronger policies around product safety, healthy environments, and accessible prevention tools. 

How have we estimated ‘at least 30%’?

At Breast Cancer UK, we have taken an estimate based on the population attributable fractions (as defined by The World Health Organisation – WHO) of diverse studies from around the world, as noted in the table below.

From the studies noted in the table below we estimate that at least 30% of breast cancer cases may be preventable. In our estimate, we have accounted for the limitation that many studies look at some risk factors and not others, as well as the fact that none of the studies incorporate an analysis of how chemical exposures may increase risk.