In the last 40 years, health care has improved a great deal and we are living longer than ever. But the downside to longevity is more time for mutations to occur, and that means cancer.

A new forecast in the British Journal of Cancer has an alarming finding - that half of people in the United Kingdom will get cancer - but it makes sense. The good news is that in the last 40 years, cancer survival has doubled and half of cancer survivors now live more than 10 years.

The 50 percent number is not new, it was always projected, but rather than being in the future the new study says it is already here for those born in the early 1960s and beyond. They forecast that a child born today has a 1 in 2 chance of developing cancer at some point in their lives.  This new estimate replaces the previous figure, calculated using a different method, which predicted that more than 1 in 3 people would develop cancer at some point in their lives.

Age is the biggest risk factor for just about every disease, including most cancers, and the increase in lifetime risk is primarily because more people are surviving farther into old age, when cancer is more common. 

Study author Professor Peter Sasieni, based at Queen Mary University of London, said, "Cancer is primarily a disease of old age, with more than 60 per cent of all cases diagnosed in people aged over 65. If people live long enough then most will get cancer at some point. But there's a lot we can do to make it less likely - like giving up smoking, being more active, drinking less alcohol and maintaining a healthy weight.

"If we want to reduce the risk of developing the disease we must redouble our efforts and take action now to better prevent the disease for future generations."

Harpal Kumar, Cancer Research UK's chief executive, said, "We need a concerted approach and a broader sense of how we can save lives and money by preventing more cancers. Growing older is the biggest risk factor for most cancers - and it's something we can't avoid. But more than four in ten cancers diagnosed each year in the UK could be prevented by changes in lifestyle - that's something we can all aim for personally so that we can stack the odds in our favor."

Professor Dame Sally C Davies, Chief Medical Officer, said, "We must set these figures in context of the fact that people are living longer because of better health care and medical advances. Cancer survival rates have improved to record levels in this country and we are working to raise awareness of cancer symptoms so it can be diagnosed earlier, improving cancer outcomes. Leading a healthy lifestyle is easily the most effective thing you can do to reduce your risk, this means being active, quitting smoking, drinking less alcohol, and having a balanced diet."

Citation: A S Ahmad, N Ormiston-Smith and PS Sasieni. 'Trends in the lifetime risk of developing cancer in Great Britain: Comparison of risk for those born in 1930 to 1960'. British Journal of Cancer, 2015. DOI: 10.1038/bjc.2014.606