Is lung cancer only caused by smoking?

No. Smoking causes most lung cancers, but it is not the only way lung cancer can happen. People who have never smoked can also develop lung cancer.

Because smoking is the leading cause, not smoking or quitting smoking is one of the most important ways to lower the risk of lung cancer. Resources such as Smokefree.gov can help people who want to quit.

At the same time, having lung cancer does not mean a person must have smoked. If you have questions about your own risk, your healthcare team can help.