Almost four in 10 cancer cases in the UK could be prevented if British people changed their lifestyles by drinking less alcohol, keeping their weight down, ditching cigarettes and avoiding overdoing it on a sunbed, among other actions, research has revealed.

New figures from Cancer Research UK (CRUK) show that more than 2,500 cancer cases a week are avoidable, with exposure to tobacco smoke the leading factor, accounting for just over 15% of cancer cases.



“Lung cancer contributes well over half of those smoking-related cases, but there are also thousands of cancers of smoking-related bladder, oesophageal and bowel cancers every year to name just a few,” said Dr Katrina Brown, lead author of the study at CRUK.

While the researchers say that smoking rates in the UK are falling by about 1% a year, they flagged growing concerns about the nation’s expanding waistline, with excess weight the second leading preventable cause of cancer, accounting for 6.3% of cancer cases.



The team said they hoped the government would learn from the success of measures such as advertising restrictions, tobacco taxes and standardised packaging in cutting smoking rates, and called for a 9pm watershed for junk food adverts and for food manufacturers to come up with new recipes to reduce salt, sugar and fat in products.



However, the team said a shift in public attitudes was also necessary, warning that obesity had the potential to become “the new smoking”.



“People regard being large as increasingly normal, and that is a shift in social norms and acceptability,” said Prof Linda Bauld, who works on behavioural research for cancer prevention at CRUK. “We need to get back down to what is the normal while recognising the challenges individuals face.”



While a recent campaign by CRUK highlighting the link between obesity and cancer was met with anger by some who accused the charity of fat-shaming, Bauld said the charity had a duty to increase awareness, noting that just 15% of adults in the UK recognised the connection between obesity and cancer.



The team say that while cancer survival is improving, the rate of new cancer cases in the UK has risen by 7% over the past decade, after taking into account the ageing population and population growth, and is expected to continue to increase by about 2% every year, making prevention important.



The new research, published in the British Journal of Cancer, is based on a number of sources, including national surveys, cancer registries and analyses of data from scientific papers.



The results reveal that drinking alcohol, having a low-fibre diet and infections such as HPV each account for just over 3% of cancer cases, with exposure to substances at work, such as asbestos, and UV radiation each causing almost 4% of cancer cases. Air pollution, eating processed meat, not breastfeeding and exposure to radiation such as radon gas each accounted for less than 2% of cancer cases. The figures took into account overlap between the different aspects of lifestyle, and only included definite causes of cancers. “What we are talking about here is at the population level: what we can’t do is say for any individual person what their risk is,” said Sir Harpal Kumar, chief executive for CRUK. “We can’t for example say if you don’t smoke you won’t get cancer, neither can we say if you do smoke you will get cancer, because these things are affected by other factors.”

The team note that the proportion of preventable cases of cancer varies between the four nations within the UK, with 41.5% of cancers avoidable in Scotland, compared to 37.3% in England – a difference Brown put down to socioeconomic factors affecting lifestyles.

Overall the proportion of avoidable cancer cases was slightly higher in men than women, probably due to higher levels of lifestyle factors such as smoking in men. However, some, such as excess weight and alcohol, were responsible for a greater proportion of cancers for women – probably because the cancers involved primarily affect women.



The percentage of cancer cases attributed to excess body weight, 6.3%, had risen from 5% as calculated in the charity’s previous report on the topic in 2011, a change that researchers say is down an increase in obesity and a rise in the number of types of cancer known to be linked to being overweight or obese. Excess weight is now linked to 13 cancers, among them cancer of the breast, kidney, bowel and womb.

The study had some limitations, including that survey data based on self-reports can be prone to error and that some of the data used was several years old.

But Kumar said action was vital: “A lot of these behaviours start quite early, and that is where we need to think about addressing them.”