Despite a recent study claiming the opposite, scientists say getting cancer isn't just bad luck in most cases. A study out of Stony Brook University shows as much as 90% of cancers are caused by external factors, like smoking, drinking, sun exposure, and air pollution, and are thus more preventable than previously thought. "There are changes that we can all make to our lifestyles to significantly reduce our risk of cancer," a rep for the World Cancer Research Fund tells the Telegraph, adding some of the most common cancers "could be prevented by adopting a more healthy diet, exercising more, and maintaining a healthy weight." Scientists note cancer is too common to be explained by mutations in cell division, as a January study suggested, though external factors can cause high rates of mutations, per the Los Angeles Times. "Intrinsic risk factors contribute only modestly to cancer development," a study author says.
Researchers reviewed several studies—including some showing those who move from countries with low cancer rates to those with high cancer rates soon develop cancer at rates consistent with their new environment—to conclude that most risk factors are environmental or linked to lifestyle. Almost 75% of the risk of colorectal cancer is related to diet, 86% of the risk of skin cancer is linked to sun exposure, and 75% of the risk of developing head and neck cancers is due to tobacco and alcohol, the study finds. It concludes 70% to 90% of cancers "would not occur if we could magic away all the risk factors" and shows "we have to look well beyond pure chance and luck to understand and protect against cancers," says a statistician. Researchers also found "mutations during cell division rarely build up to the point of producing cancer," according to Nature. (Soon, hardly anyone under 80 will die of cancer.)