A new research conducted in the US has defied an earlier finding that blamed random cell mutations for a majority of cancers. The research instead cites smoking, drinking, exposure to sun and air pollution as the main reasons behind most of the tumours.

Conducted by scientists at Stony Brook University in New York, the study suggests that environmental and external factors play a much greater role in cancer incidence than simple mutations in cell division. The researchers say as such, several cancers may be more preventable than previously thought.

The finding may generate a lot of debate as it suggests that mere lifestyle changes, including staying away from the sun, minimizing the use or giving up cigarettes and following a strict exercise regimen, could considerably cut down the risk of developing cancer.

A controversy is more likely to erupt as a study published earlier this year had suggested that up to 65% of the cancers occurred due to random mistakes in cell division, thus signifying that these were not in our control.

Supporting the latest finding, a British researcher even went to the extent of saying that up to 90% of the cancers would not occur if the lifestyle suggestions were followed religiously.

Yusuf Hannun, who was part of the study, said: “Here we provide evidence that intrinsic risk factors contribute only modestly to cancer development. The rates of mutation accumulation by intrinsic processes are not sufficient to account for the observed cancer risks”.

The research claims that around 75% of the risk of colorectal cancer was now believed to be due to diet. Similarly, 75% skin cancer cases are to be blamed on exposure to sun while head and neck cancers could be due to tobacco and alcohol.