Up to 90% of Cancer Cases Caused by Lifestyle or Environment, Study Says
It’s a longtime debate in oncology circles: is cancer mainly caused by environmental factors, or does it mostly come down to cellular luck? The answer is: both. But a new study published in the journal Nature concludes that the vast majority of cancers can be traced to lifestyle and environmental factors, many (though certainly not all) of which are controllable.
The research concludes that only 10% to 30% of cancers are the result of a natural mutation. The rest — up to 90% — are caused by external factors such as smoking, environmental toxins, or dietary choices. Of course, some bad luck is involved in all cases. Some heavy smokers never get cancer, and some non-smokers are afflicted by cancers that usually only affect tobacco users.
It’s likely to add more fuel to an ongoing debate. In another study published in January by the journal Science, researchers concluded the opposite — finding that about two-thirds of cancers can be attributed to “bad luck” — a cell that just happened to mutate.
For the new study, researchers at the Stony Brook Cancer Center in New York studied the issue from several angles: genetic studies, population data, and computer modeling.
Outsiders have said the research seems sound. One of them, Emma Smith of Cancer Research UK, told the BBC that the study shows that while “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.”
Still, nobody should draw broad conclusions based on any individual study. Nature itself addressed this point today in an article titled, “Cancer Studies Clash Over Mechanisms of Malignancy.”
Nature quoted researcher John Potter, from the Fred Hutchinson Cancer Research Center in Seattle, as saying there’s “no question what’s at stake” in this debate. Potter is from the Fred Hutchinson Cancer Research Center in Seattle. “This informs whether or not we expend energy on prevention,” he said. The implications are big for where research money will go, and perhaps ultimately for how business will be regulated by agencies such as the Food and Drug Administration and the Environmental Protection Agency.
As for the rest of us, there’s universal agreement that at least some cancers are caused primarily by environmental factors and personal behaviors, so expending energy on prevention can’t hurt.