Our Science Surgery series answers your cancer science questions.
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Victoria asked: “Will cancer ever be eradicated completely?”
We’ve already written about whether all cancers will ever be curable, which you can read about here. But wiping out cancer completely is another kettle of fish.
Is cancer preventable?
1979 was an important year for world health. Smallpox – a disease that had plagued the planet for some 3,000 years – was declared eradicated. 30 years later, the world officially waved goodbye to a second disease: rinderpest, which affected animals and livestock.
Alongside a lengthy global effort, there was another crucial factor behind these success stories. Both diseases were preventable.
They were caused by viruses. And scientists developed vaccines against them. Viruses are parasites and can’t survive on their own; they need a ‘host’ to hitchhike on. By using an effective vaccine to stop people and animals from getting infected, the viruses couldn’t keep going on earth. So, they disappeared.
The key difference here is that, unlike smallpox and rinderpest, cancers don’t have a single cause, and not all cases are preventable.
“We suspect that around 40% of cancers are preventable, through changes like not smoking, drinking less alcohol and keeping a healthy weight,” says Professor Richard Martin, a Cancer Research UK-funded expert on cancer prevention at the University of Bristol.
“It may well be that some of the remaining 60% are down to factors in our environment that we don’t yet know about, but many will be caused by genetic changes that happen by chance.”
That means a significant chunk of cancers could be prevented by altering different aspects of our lives. But Martin also sees this knowledge as a further opportunity to cut cancer rates.
“Looking at lifestyle factors is of great interest, because we can then think of ways to make it easy for people to make changes,” he says. “But if we can understand the mechanisms underpinning convincing causes of cancer, then we could probably go some way to preventing other cancers too.”
Martin points out the example of aspirin, which is now being looked at as a potential way to prevent several different cancers – including by our scientists. Aspirin is an anti-inflammatory drug. And it was the discovery that long-term inflammation is linked with cancer, for example through obesity, that drove scientists to test this idea out.
What about genetics?
Since many cancers are caused by factors out of our control, such as genetic mistakes that happen when a cell copies itself, preventing these seems more in the realms of science-fiction than possibility – at least with today’s understanding and medicine.
A more feasible alternative could be to stop cancers from progressing.
For many scientists, the ‘holy grail’ of cancer research is to develop a simple, one-size-fits-all test that could pick up the earliest warning signs of cancer. A popular vision would be to use such a test in the general population, to pick up cancers at early stages, before they cause symptoms, and before they become difficult to treat.
It’s not just about detecting cancers, it’s detecting cancers that matter.
– Prof Richard Martin, Cancer Research UK
The idea would then be to intervene quickly, for example with surgery or drugs, and nip the problem in the bud. But this relies on many things. The test would have to be accurate enough to not give false results in healthy people, so that people who don’t have cancer aren’t given treatments they don’t need. It would also need to be able to tell exactly where the developing cancer is in the body, so that the right treatment can be chosen.
Martin also highlights another issue: overdiagnosis.
“It’s not just about detecting cancers, it’s detecting cancers that matter, and not identifying cancers or cancerous changes that may never go on to cause harm.
“That’s becoming the increasing problem.”
Despite suggestive headlines, such a test doesn’t yet exist.
Long story short
So, what’s the take-home message? Martin sums it up for us: “Cancer isn’t completely preventable, so we can’t prevent all cancers. But it’s not just about prevention; it’s about reducing the burden of cancer when it’s there.
“And we’re making great progress.”
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