More than 2,500 cancer cases diagnosed every week in the UK are preventable by making simple lifestyle changes, research has found.
Almost four in ten of all cancers could be avoided by switching to a healthier diet, doing more exercise and giving up smoking.
Of the 360,000 new cases diagnosed in 2015, about 135,500 could have been prevented, according to Cancer Research UK.
Experts say it is further evidence that cancer is largely down to environmental factors – especially the unhealthy lifestyles rife in Britain – and not simply caused by genes or ‘bad luck’.
While smoking is still the biggest avoidable cause, accounting for three in every 20 cases, doctors say weight-related cancer is fast catching up.
Soaring levels of obesity, combined with the falling smoking rates, mean it could overtake smoking as the top preventable cause in the next 20 years.
And women are at higher risk than men because obesity is a key factor in breast, womb and bowel cancers. Harpal Kumar, chief executive of Cancer Research UK, said the nation was facing an obesity-led cancer timebomb.
He said the research linking cancer and obesity was still limited and suggested the effects from today’s obesity epidemic could take between ten and 20 years to play out.
‘Obesity is potentially the new smoking,’ he said. ‘We need to turn that tide around and we need to act quickly.’
Janet Boak, 55, was diagnosed with womb cancer four years ago and says her weight and lifestyle were to blame.
The grandmother of three, from Carlisle, said she weighed 20 stone at the time and admits she did no exercise.
She underwent a hysterectomy but had no further treatment as the disease had been caught early.
Volunteering to take part in womb cancer research, she was shocked to discover that possible causes include being obese and inactive.
She said: ‘I was huge and most of my weight was around my stomach. I couldn’t remember the last time I did any exercise.
‘I’d known I needed to lose weight but I hadn’t realised just how much I was putting my life at risk.’