One in three of us will develop a form of cancer in our lifetimes, and the search for risk factors and treatments looms large in every country's medical research budgets. Billions of pounds a year are spent in the UK by the government, charities and pharmaceutical companies in tackling this disease - either in the form of basic genetics research to identify who is susceptible, better drugs to treat the damage it causes, or working out how people can live their lives to avoid as many of the risks as possible.
So recent figures released by Cancer Research UK (Cruk) and the UK Association of Cancer Registries might have alarmed anyone convinced that increasing money and focus on the disease were effective in tackling the problem. Their survey showed a rise in many of the cancers that are exacerbated by our lifestyle: diagnoses of melanomas, the most dangerous type of skin cancer, have increased by 43% over the last decade, of oral cancer by 23%, of womb cancer by 21% and kidney cancer by 14%. This despite endless education campaigns that fashion the latest science into bite-size chunks of advice on how to eat to avoid getting fat (a risk factor for womb cancer), why we should stay out of the sun (an important one for melanoma) or what happens when we smoke (a risk factor for everything). Never have people been more aware of how their lifestyle influences the diseases from which they will end up suffering. Have the campaigns failed?
Well, no. For a start, there is a latency with cancer - sunbathe too much today and you probably won't see the cancerous effects, if any, for at least a decade, perhaps more. The cases of melanoma reported in this week's survey - about 8,000 every year in the UK, which cause more than 1,800 deaths - are mainly in people who indulged in too much sun in the 1980s, more than a decade before the government began to think about telling people it was a bad idea to turn your skin lobster-red on a regular basis.
But get on top of one risk factor, and you are likely to uncover another waiting in the wings. The increase in mouth cancer is perhaps surprising given that one of its main causes, smoking, has been in decline for so long. For more than 50 years, we have known this particular lifestyle choice is a death sentence that is responsible for countless adverse long-term health effects. The confounding factor here is alcohol, a potent risk factor for mouth-related cancers. According to a study by the Institute of Alcohol Studies, the average amount we drink per person has doubled in the last half-century.
As for skin cancer, in 1971 Britons made 4.2m trips abroad for holidays. By 2004, that was up to 44.2m. The cheap flight revolution of the last 10 years has given all of us an easy way to escape grey skies at home. Spain, Italy and the south of France now share their copious sunshine with legions of pale-skinned Brits who prefer to sunbathe for two grateful weeks rather than sit in the shade, like many of the indigenous people. You don't need an epidemiological study to know that this behaviour will increase the number of melanomas during the coming decades.
Cancer is a moving target that conspires with a widening range of biochemical and behavioural factors to attack our bodies. The more we know about it, the more frightening it can seem. But that knowledge is also empowering: the billions we spend have gone a long way to change the mindset of hopelessness. Cruk says about half of cancers can be prevented by changes in lifestyle. Where once cancer was a disease people faced with grim inevitability, the modern view arms us with a new optimism: identify the things that place you at risk and you get a big say in whether this devastating disease comes knocking.
alok.jha@theguardian.com
