More than 40 per cent of all UK cancer cases could be prevented by avoiding unhealthy lifestyles and environmental risks, according to the biggest study of its kind into diseases that kill more than 150,000 people a year.
Smoking, bad diets, alcohol and being overweight cause more than 100,000 tumours every year – a third of all preventable cancers.
The figure increases to 134,000 when all 14 risk factors – including sun exposure, occupational hazards, infections and hormone replacement therapy – are taken into account.
The findings, published by Cancer Research UK, are based on figures from 2010 and provide one of the most comprehensive pictures of the links between lifestyle and cancer to date.
The study, in the British Journal of Cancer, will put further pressure on the Government to tackle smoking rates, obesity levels, binge drinking and the use of sunbeds by teenagers.
Currently, the authorities rely on voluntary agreements from industries concerned. Last night, health experts called for more focus on prevention to deal with the growing burden of lifestyle-related diseases.
Many risk factors analysed are strongly linked to other killers such as heart disease, stroke and diabetes.
Sir Richard Thompson, president of the Royal College of Physicians, said: "These stark new figures are a wake-up call to the Government to take stronger action on public health.
"The rising incidence of preventable cancers shows that the 'carrot' approach of voluntary agreements with industry is not enough to prompt healthy behaviours and needs to be replaced by the 'stick' approach of legislative solutions."
Dr Harpal Kumar, chief executive of Cancer Research UK, said the healthcare system was tilted disproportionately towards treatment.
"If we could prevent 134,000 cancers a year this would lead to enormous savings in health costs, so there is a credible case to be made for more resources in prevention," he said.
The review confirmed tobacco as the worst offender, responsible for one in five – 60,000 – cases a year. Smoking is to blame for nine in 10 lung cancer victims but is a bigger risk factor than even alcohol in liver cancer.
Not eating the recommended five portions of fruit and vegetables a day accounted for 20,000 cancer cases each year, chiefly mouth, throat and oesophagus tumours.