Why it's done

The goal of lung cancer screening is to detect lung cancer at a very early stage — when it's more likely to be cured. By the time lung cancer signs and symptoms develop, the cancer is usually too advanced for curative treatment. Studies show lung cancer screening reduces the risk of dying of lung cancer.

Who should consider screening

Lung cancer screening is usually reserved for people with the greatest risk of lung cancer, including:

• Older adults who are current or former smokers. Lung cancer screening is generally offered to smokers and former smokers who are 50 and older.

• People who have smoked heavily for many years. You may consider lung cancer screening if you have a history of smoking for 20 pack years or longer. Pack years are calculated by multiplying the number of packs of cigarettes smoked a day and the number of years that you smoked.

  For example, a person with 20 pack years of smoking history may have smoked a pack a day for 20 years, two packs a day for 10 years or half of a pack a day for 40 years. Even if your smoking habits changed over the years, your recollection about your smoking history can be used to determine whether lung cancer screening may be beneficial for you.

• People who once smoked heavily but quit. If you were a heavy smoker for a long time and you quit smoking in the last 15 years, you may consider lung cancer screening.

• People in generally good health. If you have serious health problems, you may be less likely to benefit from lung cancer screening and more likely to experience complications from follow-up tests. For this reason, lung cancer screening is offered to people who are in generally good health.

  Screening is generally not recommended for those who have poor lung function or other serious conditions that would make surgery difficult. This might include people who need continuous supplemental oxygen, have experienced unexplained weight loss in the past year, have coughed up blood recently or have had a chest CT scan in the last year.

• People with a history of lung cancer. If you were treated for lung cancer more than five years ago, you may consider lung cancer screening.
• People with other risk factors for lung cancer. People who have other risk factors for lung cancer may include those with chronic obstructive pulmonary disease (COPD), those with a family history of lung cancer and those who have been exposed to asbestos at work.

How long to continue screening

Not all medical groups agree on the age at which you may consider stopping lung cancer screening. In general, continue annual lung cancer screening until you reach a point at which you're unlikely to benefit from screening, such as when you develop other serious health conditions that may make you too frail to undergo lung cancer treatment.