There is an alarming ignorance about cancer and how to reduce the risk of the disease, a survey has suggested.
Cancer is a major killer
Many of the 4,000 British people questioned were unaware that diet, alcohol and weight were all factors that can influence the risk.
The study was commissioned by Cancer Research UK, which is launching a campaign to promote lifestyle changes which cut the odds of getting cancer.
Research suggests that at least half of all cases of cancer could be prevented.
But Cancer Research UK says that message has not go through to the public.
The survey results reveal much confusion about what increases the risk of cancer.
Reduce the risk
Stay in shape
Eat a healthy balanced diet, including plenty of fruit and vegetables
Limit alcohol consumption
Keep tabs on any changes in your body
Cover up in the sun
Of the 4,000 people questioned, two-thirds (66%) were unaware that being overweight or obese increases the risk of some cancers.
A similar figure (67%) did not know that a diet low in fruit and vegetables could increase their chance of getting the disease.
Only one-third mentioned drinking less alcohol as a way of reducing risk.
And around 75% were ignorant of the cancer risks posed by taking HRT or having many sexual partners.
In contrast, almost a quarter (24%) believed living near power lines was a risk. And more than one-third (34%) thought stress was linked to cancer.
There is no strong scientific evidence to support either of these beliefs.
The survey did find that the majority of people are aware that cancer is linked to smoking and over-exposure to the sun.
Professor Alex Markham, chief executive of Cancer Research UK, said: "The fundamental aim of this campaign is to alert everyone to the fact that each one of us can reduce our risk of getting cancer.
"There is no magic pill to prevent us getting the disease but there are many things we can all do in our daily lives to improve our chances of avoiding it."
The Reduce the Risk campaign will target thousands of GP surgeries, health promotion units, hospitals and outpatient departments with leaflets and posters on its key messages.
Information will be distributed to local authority leisure centres, swimming pools and shopping centres.
Jola Gore-Booth, chief executive of the charity Colon Cancer Concern, said: "Making people aware of these factors is a significant challenge when it comes to bowel cancer: people often find it embarrassing to talk about this part of their body.
"Yet when diagnosed in its early stages, bowel cancer is highly treatable - hence raising awareness is so important."
Cancer is diagnosed in more than 270,000 people in Britain each year.