One in two people will be diagnosed with cancer in their lifetime, according to Cancer Research UK, which says more effort must be made to prevent people getting the disease and that the NHS must plan to treat more patients.

Until now, CRUK’s scientists have estimated that one in three people would get cancer at some point. The new figure, from a paper published on Wednesday in the British Journal of Cancer, is derived from a more accurate way of calculating the risk, says the charity. It means that half of those born after 1960 can now expect a diagnosis at some point in the future. For those born earlier, the risk remains at one in three.

More people are getting cancer mainly because they are living longer. “Cancer is primarily a disease of old age, with more than 60% of all cases diagnosed in people aged over 65,” said the author of the paper, Prof Peter Sasieni, based at Queen Mary University London. “If people live long enough, most will get cancer at some point.”

The new calculation comes from a different way of assessing people’s lifetime risk of cancer. In the past, it has been worked out on the assumption that the risk people are born with remains the same throughout their life. This paper takes into account the changes in the population into the future – principally more people growing older, but also changes in people’s eating, drinking, smoking, and other lifestyle habits that have an effect on cancer rates. It finds therefore that the risk of cancer for somebody born before 1960 is lower than that of somebody born after that date, which will be partly because those born later are likely to live longer.

The lifetime risk for women is lower than that for men, at 47.5% compared with 53.5%, the paper says.

CRUK and Sasieni point out that many cancers are preventable. “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,” said Sasieni.

“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.”

While more people may get cancer, more are beating it as well. Cancer survival has enormously improved, says CRUK, doubling since the 1970s through earlier detection and improved treatment. Half of those newly diagnosed with cancer will survive for at least 10 years. But chief executive Harpal Kumar said there would never be a single cure for cancer. There are 200 types of cancer and they are all quite different, he said. “There will never be one single magic bullet that … cures all cancers. I cannot foresee a time when that’s going to be the case. But already we’re able to cure a number of cancers now.”

However, the burden of new cases on the NHS will be severe, says the charity. “We’re living longer, and that means we’re more likely to develop a range of age-related health issues,” said Kumar. “We need to plan ahead to make sure the NHS is fit to cope. If the NHS doesn’t act and invest now, we will face a crisis in the future – with outcomes from cancer going backwards.

“As [NHS chief executive] Simon Stevens set out in the NHS Five Year Forward View, we need better planning and innovative design of services. We also need to ensure the health service is adequately funded if we’re to deal effectively with the growing burden of cancer and offer all patients the best chance of long-term survival.”

Prevention is key to saving lives and saving money, he said. More than four in every 10 cancers could be prevented by changes in people’s lifestyles.

Chief medical officer Dame Sally Davies said that cancer survival rates had improved to record levels in Britain.

Ellie Rose, public affairs manager at Macmillan Cancer Support, said the latest figures pose “a herculean challenge for the NHS and for society. With cracks already beginning to show, the NHS will soon be unable to cope with the huge increase in demand for services – meaning the support that organisations like Macmillan provide will become even more critical.

“Whichever party is voted in at this year’s election will need to make sure the NHS is ready to support the colossal wave of people who will be diagnosed with cancer during their time in power.”