Smoking can increase the risk of developing non-small cell lung cancer.

Smoking cigarettes or cigars is the most common cause of lung cancer. The more years a person smokes, the greater the risk. If a person has stopped smoking, the risk becomes lower as the years pass, but is never completely gone.

Anything that increases a person's chance of developing a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for lung cancer include the following:

• Smoking cigarettes or cigars, now or in the past.
• Being exposed to second-hand smoke.
• Being treated with radiation therapy to the breast or chest.
• Being exposed to asbestos, radon, chromium, arsenic, soot, or tar.
• Living where there is air pollution.

When smoking is combined with other risk factors, the risk of developing lung cancer is increased.