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I'm a cancer expert - this is why it is not a 'man-made' disease

The i logo The i 08/09/2018 Professor Charlie Swanton
a screen shot of a computer monitor sitting on top of a television © Provided by Johnston Publishing Ltd Cancer has existed even longer than humans have walked the Earth. From being discovered in dinosaur bones, in the ‘duck-billed’ hadrosaurs, to the Egyptian mummies of 4, 000 years ago, it is clear that cancer is far from a ‘modern’ disease.

Yet despite its long history we often see claims cancer is ‘man-made’, stemming from undue hype from small or early studies, or promotion from health ‘gurus’ around stress, power lines and deodorants, to list just a few.

Although there are no links between these factors and cancer, it is certainly true that global lifestyle-related diseases like cancer are on the rise, perhaps adding fuel to the myth that cancer is ‘man-made’.

'Over half of all cancers are in people over 70 years old.'

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© Provided by Getty However, it’s important to remember that this rise is being accelerated by our ageing population with age being the biggest risk factor for cancer. In fact, over half of all cancers are in people over 70 years old.

Today, people are living almost twice as long as 150 years ago, and over time the cells in our body can become damaged. Although our bodies are remarkably good at repairing this damage, some DNA damage in our cells builds up as we age. This leads to more and more genetic faults accumulating over time, increasing the chance that eventually a cell will turn cancerous.

The external factors that affect us too

In a small proportion of people, this risk is also increased by inherited faulty genes, such as BRCA1 and BRCA2 genes, which hampers the cells’ ability to repair broken DNA, increasing the risk of certain cancers.

Time, however, is not the only contributor to cancer. There are external factors that can increase our risk of cancer too. For example, one in six worldwide cancers are attributed to viruses and bacteria. For this reason, we are seeing targeted cancer vaccines being developed, like the human papilloma virus (HPV) vaccine. This vaccine provides protection against the main types of high-risk HPV infection that account for an estimated 7 in 10 cases of cervical cancer.

Related: Behaviours that significantly increase the risk of cancer (Provided by The Active Times)

Yet, while in its entirety the thought that cancer is ‘man-made’ is a myth, Cancer Research UK studies show that 4 in 10 cancer cases in the UK could be prevented. These preventable risk factors, such as smoking and obesity, contribute to many different types of cancer. While smoking is responsible for around 7 in 10 lung cancers in the UK, it’s also linked to other types of cancer that are hard to treat, including pancreatic and oesophageal cancer.

'At the moment, lung cancer has a terrible outlook, with only 5 per cent of people surviving more than 10 years. Symptoms can often be vague'

In these cancers, survival hasn’t seen the same improvement over the years that others have, remaining stubbornly low. Seeing these patients first hand in the clinic, I know how devastating the disease can be. At the moment, lung cancer has a terrible outlook, with only 5 per cent of people surviving more than 10 years. Symptoms can often be vague, like breathlessness or unexplained weight loss, which means it’s more likely to be diagnosed late, when the disease is far more difficult to treat.

© Provided by Getty For many of the patients I see, the outlook is bleak. As a result, preventing even some of these cancers could have a huge impact. Beyond smoking and obesity, there are numerous other preventable causes of cancer, from UV exposure from the sun to alcohol. So, although there are factors linked to our genes and the body’s natural ageing process that are beyond our control, there are also ways we can stack the odds in our favour.

But more people are surviving

The good news is that, although our population is getting older and we are seeing more cases of cancer, it’s also true that more people are surviving. Survival has doubled in the last 40 years so that, today, two in four people survive their disease for 10 years or more. Cancer Research UK’s ambition, through the work our researchers, doctors and nurses do is to see that figure rise to three in four by 2034.

In the meantime, for those looking for more information on what they can do to reduce their risk, the Cancer Research UK website has details on the current evidence around cancer risk.”

Professor Charlie Swanton is Cancer Research UK's Chief Clinician

Related: 16 Unexpected Cancer Symptoms Every Woman Should Know (Provided by


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