Earlier this year, researchers sparked a debate after suggesting two-thirds of cancer types were down to luck rather than factors such as smoking.
The 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”.
Cancer is caused by one of the body’s own stem cells going rogue and dividing out of control.
That can be caused either by intrinsic factors that are part of the innate way the body operates, such as the risk of mutations occurring every time a cell divides, or extrinsic factors such as smoking, UV radiation and many others that have not been identified.
The argument has been about the relative importance of intrinsic and extrinsic factors.
In January, a report in the journal Science tried to explain why some tissues were millions of times more vulnerable to developing cancer than others.
Their explanation came down to the number of times a cell divides, which is out of our control and gave rise to the ‘bad luck’ hypothesis.
In the latest study, a team of doctors from the Stony Brook Cancer Centre in New York approached the problem from different angles, including computer modelling, population data and genetic approaches.
They said the results consistently suggested 70-90% of the risk was due to extrinsic factors.
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