Cancer is overwhelmingly a result of environmental factors and not largely down to bad luck, the BBC reported today.

Earlier this year, researchers sparked a debate after suggesting two-thirds of cancer types were down to luck rather than factors such as smoking.

A new study, in the journal Nature, used four approaches to conclude only 10-30% of cancers were down to the way the body naturally functions or "luck".

Experts said the analysis was "pretty convincing".

A team of doctors from the Stony Brook Cancer Centre in New York found that external factors play a big role, and people cannot hide behind bad luck.

"They can't smoke and say it's bad luck if they have cancer. It is like a revolver, intrinsic risk is one bullet. And if playing Russian roulette, then maybe one in six will get cancer - that's the intrinsic bad luck.

"Now, what a smoker does is add two or three more bullets to that revolver. And now, they pull the trigger. There is still an element of luck as not every smoker gets cancer, but they have stacked the odds against them.

"From a public health point of view, we want to remove as many bullets as possible from the chamber."

There is still an issue as not all of the extrinsic risk has been identified and not all of it may be avoidable. 

Dr Emma Smith, from Cancer Research UK, said: "While healthy habits like not smoking, keeping a healthy weight, eating a healthy diet and cutting back on alcohol are not a guarantee against cancer, they do dramatically reduce the risk of developing the disease." 

http://www.bbc.com/news/health-35111449