If you hear about someone with lung cancer, you may wonder if they smoke or even assume that they do (or did in the past). But the truth is that as many as 20 percent of lung cancers in the U.S. are in people who have never smoked. Smokers and nonsmokers tend to develop different types of lung cancer. Smoking tobacco is the leading risk factor for small cell lung cancer (SCLC), which is responsible for 98 percent of all SCLC diagnoses. Nonsmokers are more likely to develop lung cancer as a result of a genetic mutation or abnormality that drives the development of cancer.
Learn more about lung cancer