The idea that lifestyle changes have made the disease more common is a gross exaggeration – but increasingly prevalent. We separate fact from fiction
Cancer is not up there with the most likely explanations for what caused the mass extinction 66m years ago of the T rex and the triceratops. That said, at least one species of dinosaur suffered from blood-vessel tumours – and a 1.7m-year-old toe with bone cancer was discovered in 2016 at a South African world heritage site.
Cancer may have been more common in ancient times than we will ever know, because fossilisation will have obliterated most evidence of the disease. However, misinterpretations of some small studies and claims by self-styled wellness gurus that cancer is “a man-made disease” have fed the belief that cancer is modern. While that does not mean anyone concerned about cancer should visit their local natural history museum for information, thinking of cancer as a result of modern life causes unnecessary fear. Here are some modern myths about cancer.
Mobile phones and wifi
There have been worries about mobile phones causing cancer since the days of playing Snake on a Nokia. Considering how widespread mobile phone use has been for decades, it would be impossible not to notice if they posed serious health risks. In the US, hardly anyone used a mobile phone in 1992. By 2008, mobile-phone use was widespread, yet the number of people who got a brain tumour barely changed. The World Health Organization’s Interphone study, which studied thousands of people across 13 countries between 2000 and 2006, also found that mobile phones did not increase a person’s chance of getting a brain tumour.
Fundamentally, cancer is caused by our DNA becoming damaged and sending normal healthy-cell-replication processes askew. Ionising radiation, such as in x-rays or radiotherapy, carries a huge amount of energy. Mobile phones, however, carry a tiny amount of energy. Breaking or stressing DNA requires a great deal of energy, far beyond the capabilities of mobile phones. Wifi, incidentally, transmits even less energy than a mobile phone.
Note, also, that not all scientific studies are created equal. Reviews or meta-analyses, where scientists look at many research studies together, give the most accurate idea of what is happening. One such review concluded: “Overall, the existing evidence for a causal relationship between RF [radiofrequency] radiation from cell phones and cancer is found to be weak to nonexistent.” The International Agency for Research on Cancer lists mobile phones as “possible carcinogens”, but this classification means only that there may be a hypothetical link that cannot be ruled out, rather than that there is a real likelihood of something causing cancer.
There is a popular belief, helped along by bloggers with dubious expertise, that organic food has “anti-cancer” properties. However, Michelle McCully, the head of research interpretation at the World Cancer Research Fund, one of the world’s leading authorities on diet and cancer, says: “There is currently no strong evidence to support the idea that organic foods offer added protection against cancer compared to conventionally grown produce.”
The Soil Association, the UK’s organic certification body, says: “Any claims around organic and cancer are not backed by strong scientific evidence.” Other benefits to organic farming are real, though, including better animal welfare, more environmentally sustainable farming (there is on average 50% more wildlife on organic farms) and reduced use of antibiotics in animals and pesticides in plants.
Chemicals and pollution
“Chemicals” is a much misunderstood word – everything, including the air we breathe, is a “chemical”. EU regulations protect us against exposure to levels of industrial chemicals that would harm our health. There is a slight risk of lung cancer associated with air pollution, but it is important to keep this in context and to realise that the risk to each individual is tiny.
Katie Edmunds from Cancer Research UK says: “In the era of fake news, there are plenty of cancer-related myths that people don’t need to worry about, such as using plastic bottles or deodorant. We know that air pollution can increase the risk of lung cancer and it’s important that the government does what it can to tackle this. But, in terms of things people can do themselves, the best advice is to stop smoking, keep a healthy weight and enjoy the sun safely.”
The grain of truth
What is true is that cancer is becoming more common. This is largely because it is a disease of old age. Many people now have cancer who in earlier times would have died much younger.
That said, some aspects of our modern lifestyles do increase our chances of getting cancer. The World Cancer Research Fund’s cancer prevention recommendations, which are based on decades of strong evidence, provide a package of healthy lifestyle choices that, along with not smoking and avoiding excess sun exposure, represent a blueprint for reducing cancer risk.
As Cancer Research UK’s Emma Shields says: “Being overweight or obese is the second-biggest preventable cause of cancer in the UK. Every year, around 22,800 cases of cancer are caused by being overweight or obese. Despite this, only 15% of people [are] aware of the link.”
Lack of exercise and consumption of alcohol are other risk factors, but anyone who wants to improve their health through diet should be particularly careful about the qualifications of the people from whom they take advice. Dietitians, who spend years in medical training, are the best people to talk to.
guardian.co.uk © Guardian News & Media Limited 2010