Over a quarter of people believe that fate will determine whether they get cancer, a survey says.
Smoking and obesity are linked to cancer
More women than men thought destiny would determine their chances - and smokers were 50% more likely than non-smokers to believe in it.
The poll of 4,000 people was carried out by the charity Cancer Research UK.
Those responding were asked if they thought they could cut their risk of developing cancer - or whether it was out of their hands.
In total, 27% of the people questioned said fate ruled whether they would be affected by the disease.
TIPS TO CUT CANCER RISK
Stop smoking - Giving up, even at the age of 60, can cut the risk of lung cancer dramatically
Be SunSmart - Protect yourself in the sun and take care not to burn
Stay in shape - Be active and keep a healthy body weight
Look after number one - Know your body and see your doctor about anything unusual
Eat and drink healthily - Limit alcohol and choose a balanced diet with plenty of fruit and vegetables
Among those from the most deprived areas, the figure rose to 43% and among those from the most privileged areas, it fell to 14%.
Smoking and obesity are linked to an increased cancer risk.
But the survey also found 34% of smokers and 36% of over 65s believed that getting cancer was down to fate.
Dr Lesley Walker, director of cancer information at the charity, said: "It is alarming that such a large percentage of the British population do not realise that half of all cases of cancer can be prevented by lifestyle changes.
"We can all reduce our risk of cancer by stopping smoking, keeping a healthy weight and eating a balanced diet with plenty of fruit and vegetables and taking plenty of exercise.
"Enjoying the sun safely and avoiding sunburn also helps to reduce cancer risk.
"Cancer Research UK's Reduce the Risk campaign is actively encouraging people to learn how they can lead healthier lives and cut their risk of developing cancer.
"We can give people information about how to do this but it is seriously worrying that so many people think cancer is down to fate."
The Reduce the Risk campaign urges people to give up smoking, eat and drink healthily, protect themselves in the sun and visit their GP if they notice anything abnormal.