This is the first post in a three-part series looking at age and cancer.
Cancer risk is complicated.
The causes of cancer can be broadly placed into two boxes: things that we can do something about, and things that we can’t. We’ve blogged about the factors we have some control over before – such as not smoking and drinking less alcohol.
But what often doesn’t get talked about is the single biggest risk factor for cancer: age.
The older you are, the more likely you are to develop cancer. And this is true for most cancer types.
Half of all cancer cases occur in people aged 70 and over in the UK. And on average, we’re living longer than ever before. These two factors help explain why the proportion of people who will be diagnosed with cancer in their lifetime has increased from 1 in 3 to 1 in 2. The good news is, cancer survival has doubled in the last 40 years.
The bigger picture
If the link between cancer and age surprises you, you’re not alone. Cancer Research UK-funded research from 2014 found that most people (64%) believed that cancer wasn’t related to age. And when comparing across similar countries, awareness of the link between cancer risk and age is particularly low in the UK.
One reason for this might be that stories about younger people with cancer tend to appear in the media more often than stories about older people .
It’s important to remember that these stories are particularly news-worthy because they are so rare.
Less than 1 in 100 new cancer cases are diagnosed in people aged under 24. These cases are important, but their coverage in the media can make these situations seem much more common than they are.
Why does age increase the risk of cancer?
It’s what happens inside our cells as we age that makes them more susceptible to turning cancerous.
Our cells contain a unique code, our DNA, that carries a set of instructions for everything a cell needs to work properly. Cells replicate themselves and their DNA to keep the body healthy.
But this replication isn’t perfect. Errors, known as mutations, occur and build up over time. If too many build up, the cell becomes faulty, and can lead to a normal cell becoming cancerous if it grows uncontrollably.
This doesn’t happen without a safety net. Our cells are normally good at spotting damaged DNA and fixing the problem so it doesn’t cause harm. But there are trillions of cells in our body, and over time some errors will get through.
The older you are, the more your cells will have replicated. So it’s likely that more DNA errors have happened and had time to build up. And because there’s more of them, it’s more likely that these errors will lead to cancer.
Mutations can occur by chance, but factors such as smoking or UV rays from the sun or sunbeds can make them more likely to happen. That’s why it’s important to tackle the factors that can be prevented
What does this mean for me?
We can’t stop the ageing process. But knowing how it increases cancer risk is an important starting point for research and awareness.
We now know that some cancer causes, such as smoking, happen through similar mechanisms to how age increases risk.
Things like smoking, too much exposure to UV rays from the sun, and drinking too much alcohol can make mutations more likely to happen. And these mutations can happen in molecules that provide the cell’s DNA repair safety net, further increasing the damage.
The link between age and the risk of different cancer types is one of the reasons why it’s generally only older people who are invited to take part in NHS screening programmes for bowel, breast, and cervical cancers.
Ageing isn’t a time bomb and not everyone will get cancer. But being aware of your body, so that you’re more likely to notice any unusual or persistent changes, can be even more important as we age.
If you do notice something that doesn’t seem right, especially if it doesn’t go away, it’s important to tell your doctor rather than put it down to age or a different health condition. Most changes won’t be cancer, but if it is, diagnosing it at an early stage means treatment is more likely to be successful.
Consider the context
Cancer awareness is important at any age, and everyone should look out for changes to their body that aren’t usual for them.
But it’s just as important to remember that around 4 in 10 cases of cancer could be prevented through things like not smoking, keeping a healthy weight and drinking less alcohol.
So don’t worry about the things you can’t change, because it’s never too late to change the things you can.
Clare Hyde is a health information officer at Cancer Research UK