Two thirds of cancers, according to a new study published on Friday, are not caused by lifestyle factors such as smoking, drinking and diet, but by chance mutations to our genes – in other words, by ‘bad luck’, The Independent reported on Saturday.
However, experts have already questioned how significant the findings are – and said it certainly is not time to throw caution to the wind.
The figure refers to cancer types, not cancer cases. Cancer Research UK say that four out of 10 cases of cancer could have been prevented by changes to lifestyle – leaving six out of 10 that could not, so it is accurate to say that most cancers are caused by bad luck rather than anything we can influence, although not quite two thirds.
However, of those cancers that are linked to lifestyle, some are the most common and most deadly. Lung cancer, the biggest cancer killer, accounting for nearly one in four deaths from cancer, is caused by smoking in more than 80 per cent of cases.
Other common cancers, such as breast cancer in women and prostate cancer in men are more closely linked to genes, but even with these, there are lifestyle factors, such as keeping fit and maintaining a healthy weight, which evidence has suggested could reduce risk.
Another study published over the festive period, carried out by Cancer Research UK, contained some striking statistics that illustrate the importance of lifestyle factors in cancer risk:
- 600,000 cancers in the UK could have been avoided in the past five years if people had healthier lifestyles
- 314,000 cases of cancer – mostly lung cancer – could have been avoided if people had given up cigarettes. A one per cent drop in the smoking rate would have saved 3,000 lives per year, Cancer Research UK estimated
- If people had eaten a balanced diet low in red and processed meat and salt, and high in vegetables, fruit and fiber, 145,000 cases could have been avoided.
- Keeping a healthy weight could have prevented 88,000 cases of cancer
- A lack of exercise was associated with 16,000 cases of cancer
- Wearing sunscreen could have avoided 55,900 cases of cancer
- Alcohol was associated with 62,200 cases of cancer – most commonly liver cancer.