Almost half of people mistakenly believe that stress causes cancer, Cancer Research UK has warned.
The charity warned that “fake news” on the internet appears to be fuelling a rise in incorrect beliefs about the causes of the disease.
Their polling found that stress, food additives, eating GM foods, and using mobile phones and microwave ovens were among the most popular “mythical” causes of cancer.
The charity said the beliefs were held despite a lack of good scientific evidence linking them to the disease.
Meanwhile, the survey found poor awareness of known cancer risk factors such as obesity, eating red or processed meat or drinking alcohol, its experts warned.
It's worrying to see so many people endorse risk factors for which there is no convincing evidence
Dr Samuel Smith, University of Leeds
Experts from University College London (UCL) and the University of Leeds said that the public's endorsement of mythical cancer causes has risen over the last decade – which might be due to more information being accessed through the internet and social media.
Researchers surveyed 1,330 people in England about their beliefs on the causes of cancer.
Participants were asked how much they agreed items on a list – which included known risk factors and "mythical" factors – can increase a person's chance of developing cancer.
The study, published in the European Journal of Cancer, found that 43 per cent wrongly thought that stress caused cancer, while 42 per cent thought food additives were a risk factor.
One quarter of people incorrectly believed that using a mobile phone was a risk factor for cancer while three in 10 falsely believe that living near power lines could be at play. Aerosols, cleaning products and artificial sweeteners were all also incorrectly identified as cancer risk factors.
All the causes have been linked to cancer in some studies, but Cancer Research said there was no good scientific evidence to support the claims.
Meanwhile, people failed to identify known risk factors, including drinking alcohol, not getting enough fruit and vegetables each day, low levels of physical activity and being over the age of 70.
Two in five failed to identify being overweight or obese as a cancer risk factor.
"Obesity was also poorly recognised, which is concerning considering it is the second leading preventable cause of cancer," the authors wrote.
Dr Samuel Smith, from the University of Leeds, said: "It's worrying to see so many people endorse risk factors for which there is no convincing evidence.
"Compared to past research it appears the number of people believing in unproven causes of cancer has increased since the start of the century which could be a result of changes to how we access news and information through the internet and social media.
"It's vital to improve public education about the causes of cancer if we want to help people make informed decisions about their lives and ensure they aren't worrying unnecessarily."
Smoking, being overweight and overexposure to UV radiation from the sun and sunbeds are the biggest preventable causes of cancer
Clare Hyde, Cancer Research UK
UCL's Dr Lion Shahab added: "People's beliefs are so important because they have an impact on the lifestyle choices they make. Those with better awareness of proven causes of cancer were more likely not to smoke and to eat more fruit and vegetables."
Clare Hyde, from Cancer Research UK, said: "Around four in 10 cancer cases could be prevented through lifestyle changes so it's crucial we have the right information to help us separate the wheat from the chaff.
"Smoking, being overweight and overexposure to UV radiation from the sun and sunbeds are the biggest preventable causes of cancer.
"There is no guarantee against getting cancer but by knowing the biggest risk factors we can stack the odds in our favour to help reduce our individual risk of the disease, rather than wasting time worrying about fake news."