Nine in 10 cancers caused by lifestyle

Environmental and external factors such as smoking, drinking, sun exposure and air pollution account for nine in 10 cancers, new study shows

Scientists at the Stony Brook University in New York now believe that outside influences have a far greater impact, meaning many cancers may be more preventable than previously thought. According to a recent study carried out by the team of researchers at Stony Brook University, environmental and external factors such as smoking, drinking, sun exposure and air pollution may account for up to nine out of 10 cancers. Researchers claimed that previously it was believed that random cell mutations played a significant role in the development of tumors

“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,” said Yusuf Hannun of Stony Brook University.

According to a statement given by Johns Hopkins University researchers in January, the more times cells divide the greater the chances that a mutation can occur, leading to cancer. They even explained the areas of the body where cell division occurred more quickly like colon, were more likely to develop tumors. As per the statistics from Cancer Research UK, about 330,000 people are diagnosed with cancer each year and 161,000 will die.

Researchers from the Stony Brook University in New York stated that if random mutations were to be blamed there would be far fewer cases than diagnosed today. Yusuf Hannun of Stony Brook University New York, US, said about 75% of the risk of colorectal cancer is now believed to be due to diet with 86% of the risk of skin cancer is down to sun exposure while 75% of chance of developing head and neck cancers is due to tobacco and alcohol. Researchers concluded that though some rare cancers are caused by genetic mutations, the most prevalent disease are down to environmental factors.

According to a report by the BBC cancer can be caused either by intrinsic factors that are part of the innate way the body operates, such as the mutations that occur every time a cell divides, or extrinsic factors such as smoking, UV radiation and many others that have not been identified. A team of doctors from the Stony Brook Cancer Centre in New York sought to proceed towards 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.

Around 330,000 people are diagnosed with cancer each year and 161,000 will die, according to statistics from Cancer Research UK. Prof Kevin Conway, Professor of Applied Statistics, The Open University, said research provided ‘pretty convincing evidence’ that external factors play a major role in many cancers. “For many common types of cancer, this study concludes that at least 70 per cent to 90 per cent of the cancers are due to external risk factors – roughly speaking, that 70 per cent to 90 per cent would not occur if we could magic away all the risk factors,” he said.

Prof Paul Pharoah, Professor of Cancer Epidemiology, University of Cambridge, said: “These findings do not have any implications for cancer treatment, but they do tell us that most cancers would be preventable if we knew all of the extrinsic risk factors that cause disease.