World Lung Cancer Day will be observed Monday, Aug. 1, which makes this a good time to learn more about lung cancer screening and who needs it.

Lung cancer is the leading cause of cancer deaths in the U.S., according to the American Cancer Society. Lung cancer claims more lives each year than colon, breast and prostate cancers combined.

Although the disease can occur in people who have never smoked, people who smoke or have smoked have the greatest risk of lung cancer. The risk of lung cancer increases with the length of time and number of cigarettes you've smoked. If you quit smoking, even after smoking for many years, you can significantly reduce your chances of developing lung cancer.

Lung cancer screening is a low-dose CT scan of the lungs to look for lung cancer. The procedure is used to detect the presence of lung cancer in otherwise healthy people with a high risk of lung cancer.

By the time lung cancer signs and symptoms develop, the cancer is usually too advanced to be cured. The goal of lung cancer screening is to detect lung cancer at an early stage — when it's more likely to be cured.

Lung cancer screening is recommended for older adults who are longtime smokers and who don't have any signs or symptoms of lung cancer.

Connect with others talking about lung cancer in the Lung Cancer support group on Mayo Clinic Connect, an online patient community moderated by Mayo Clinic.