One in two people will develop cancer at some point in their lives, new figures suggest.
A forecast from Cancer Research UK predicts that the UK could face a "crisis" if the NHS does not plan ahead.
The news coincides with World Cancer Day, which aims to take a positive and proactive approach to the fight against cancer.
The new figure, which replaces the previous of one in three, is the most accurate forecast to date from the charity and is published in the British Journal of Cancer.
Cancer Research UK said it highlights the urgent need to bolster public health and NHS cancer services so they can cope with a growing and ageing population and the looming demands for better diagnostics, treatments and earlier diagnosis.
Prevention must also play a role in the effort required to reduce the impact of the disease in coming decades, as there will "never be one single magic bullet" to cure all cancers.
Additionally, age is the biggest risk factor for most forms of the disease.
The UK's cancer survival has doubled over the last 40 years and around half of patients now survive the disease for more than 10 years.
But as more people benefit from improved healthcare and longer life expectancy, the number of cancer cases is expected to rise.
This new research estimating lifetime risk replaces the previous figure, calculated using a different method, which predicted that more than one in three people would develop cancer at some point in their lives.
The charity said age is the biggest risk factor for most cancers, and the increase in lifetime risk is primarily because more people are surviving into old age, when cancer is more common.
The results show that people who were born in 1930 had a lifetime risk of just over one in three, but the risk has risen to one in two for those born in 1960.
The lifetime cancer risk for women (47.55%) is lower than that of men (53.5%), while the combined lifetime risk is 50.5%. The risk is also expected to increase further in the future.
While the biggest risk factor is age, other lifestyle factors include smoking, obesity, diet, tanning and sunburn, overdiagnosis, lack of exercise and child-bearing patterns.
Male smoking rates are down, however overall smoking rates in the UK are at 19%, while they are at 12% in Australia.
Despite the statistic that one in two people will develop cancer, it is believed that one in four people will die from the disease.
Harpal Kumar, Cancer Research UK's chief executive, said: "We're living longer and that means we're more likely to develop a range of age-related health issues.
"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."
He said "better planning and innovative design of services" are needed, adding: "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."
When asked about how near a cure for cancer is, Mr Kumar said: "There will never be one single magic bullet that treats or 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."
Mr Kumar said there are more than 200 different types of cancers and they are all quite different.
"Once you break it down into those different diseases, we know that actually for some types of cancers we effectively do have a cure. So if you look at testicular cancer we're up at survival rates in the high nineties now," he said.
The single biggest thing that affects whether a patient is cured is whether their disease is caught early enough, Mr Kumar said.
"We know that too many cancers are diagnosed very late and once they're more advanced it becomes much harder to cure. We can treat them, we can extend life but it becomes much harder to cure," he added.
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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% of all cases diagnosed in people aged over 65. If people live long enough then most will get cancer at some point."
Prof Sasieni said breast cancer is the most common form in women, prostate cancer is the most common form in men, and bowel cancer and lung cancer are common in both sexes.
He said rates of cancer of the oesophagus are "increasing rapidly" while stomach cancer is now "far less common".
Dr Emma King, a head and neck cancer surgeon, also spoke of the importance of encouraging "earlier presentation of patients with cancer".
Ellie Rose, public affairs manager at Macmillan Cancer Support, said the latest figures pose "a herculean challenge for the NHS and for society".
She said: "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.
"That's why Macmillan is calling on all political parties to urgently prioritise cancer care in their manifestos.
"This is not just about improving the quality of diagnosis and treatment, but also about ensuring that every single person with cancer is treated with the highest levels of dignity and respect."
A Department of Health spokeswoman said: "Cancer survival rates are now at their highest ever level, and we are on track to save an extra 12,000 lives this year. But cases of cancer are likely to rise with an ageing population - so we are focused on earlier diagnosis, improving care and tackling preventable cancer.
"We have spent an extra £750 million on cancer services and have given local authorities £8.2 billion over three years to tackle public health issues, such as smoking, obesity and alcohol abuse, which are risk factors."
Siobhan Dunn, chief executive at Teenage Cancer Trust, said: "Every day seven young people across the UK are diagnosed with cancer. Cancer kills more teenagers and young adults than any other disease.
"For 20 years we have been delivering sessions in schools about the signs of cancer and healthy living. We know that empowering young people to take control of their health can not only lead to earlier diagnosis and help prevent the unacceptable delays young people suffer but also reduce the risk of developing the disease later in life.
"We now need the Government and the national cancer strategy to get behind this work so that every young person can be better educated about cancer."