Why are cancer rates increasing?

Our new figures today demonstrate the impact of cancer on society with more accuracy.

Half of us will hear the words “you have cancer” at some point in our lives.

That’s a stark figure. And it’s a reminder, if ever one were needed, of the challenge we face in beating this disease.

This isn’t to say we’re not making progress: more people are beating cancer today than ever before. Survival has doubled in the last 40 years. And half of people diagnosed will survive their cancer for more than 10 years, an all-time high.

But alongside the undeniable improvements in care, we need to talk about the scale of the problem.

Previously we’ve calculated that more than one person in three would develop cancer at some point during their life – in other words, the so-called ‘lifetime risk’ was more than 1 in 3.

But our latest estimate, which uses the most accurate calculation method to date, now puts our chances of developing the disease at 1 in 2.

Let’s be clear – this isn’t a sudden increase in risk. The different numbers are down to a change in the method used to make the calculation. But they reveal a gradual increase in risk, that’s taken place over decades.

So this begs the obvious question: just why is our risk increasing?

The simple answer is, as the animation above shows: most of us are living longer.

Growing problem

By far the biggest risk factor for most cancers is simply getting older. More than three-quarters of all people diagnosed with cancer in the UK are over the age of 60.

And this is because cancer is a disease of our genes – the bits of DNA code that hold the instructions for all of the microscopic machinery inside our cells. Over time, mistakes accumulate in this code – scientists can now see them stamped in cancer’s DNA. And it’s these mistakes that can kick start a cell’s journey towards becoming cancerous.

The longer we live, the more time we have for errors to build up. And so, as time passes, our risk of developing cancer goes up, as we accumulate more of these faults in our genes.

In the graph below, you can see how UK life expectancy has increased over time and the number of people living into old age is higher than ever before.

This means there are now more people than ever living to an age where they have a higher risk of developing cancer.

But we can stack the odds of avoiding cancer in our favour. Things that happen throughout our lives can speed up – or slow down – the rate at which errors occur in our genes. These include things we can control, and some we can’t.

They include our lifestyle, our genetics & family history, our exposure to viruses, the job we do, the air we breathe – and they can all play different roles in our overall risk of developing the disease.

Specific cancers, specific reasons

The main reason cancer risk overall is rising is because of our increasing lifespan. And the researchers behind these new statistics reckon that about two-thirds of the increase is due to longevity.

The rest, they think, is caused by changes in cancer rates across different age groups. And when you look at these changes in detail, you can see patterns reflected in how we live our lives, clearly showing how important an impact our lifestyle can have.

For example, diets high in red and processed meats have contributed to the rise in bowel cancer cases. And more and more people are becoming overweight and obese in the UK, which raises the risk of developing a number of cancers. And our culture of sunbathing and using sunbeds is contributing to rising rates of melanoma skin cancer.