Lung cancer screening

Lung cancer screening is a test to look for signs of lung cancer in otherwise healthy people. Lung cancer screening is recommended for older adults who are longtime smokers.

Doctors use a low-dose computerized tomography (CT) scan of the lungs to look for lung cancer. If lung cancer is detected at a very early stage, it may be more likely to be cured.

Discuss the benefits and risks of lung cancer screening with your doctor. Together you can review your risk of lung cancer and decide whether screening is right for you.

Why it's done Risks How you prepare What you can expect Results

The goal of lung cancer screening is to detect lung cancer at a very early stage — when it's more likely to be cured. Studies show lung cancer screening reduces the risk of dying of lung cancer.

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 older than 55.
  • People who have smoked heavily for many years. You may consider lung cancer screening if you have a history of smoking for 30 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.

    To reach 30 pack years of smoking, you'd need to smoke a pack a day for 30 years or two packs a day for 15 years. Your smoking habits may have changed over the years, so discuss your particular situation with your doctor to calculate your number of pack years.

  • 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, such as advanced heart disease, you may be less likely to benefit from lung cancer screening. And you may be 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.

Discuss your risk of lung cancer with your doctor. Together you may consider other risk factors in your decision about lung cancer screening, such as a family history of lung cancer, exposure to high levels of radon gas in your home or working with asbestos.

Lung cancer screening carries several risks, such as:

  • Undergoing unnecessary follow-up tests. If your lung CT scan shows a suspicious spot in your lung, you may need to undergo more-powerful scans that expose you to additional radiation and invasive tests, which carry serious risks. If these additional tests show that you don't have lung cancer, you may have been exposed to serious risks for no reason.
  • Finding cancer that's too advanced to cure. Advanced and aggressive lung cancers may not respond to treatment, so finding these cancers on a lung cancer screening test might not extend your life.
  • Finding cancer that may never hurt you. Doctors can't know which cancers will never grow to hurt you and which ones must be removed quickly to avoid harm. If you're diagnosed with lung cancer, your doctor will likely recommend treatment. But if the cancer would have remained small and confined for the rest of your life, the treatment may have been unnecessary.
  • Missing cancers. It's possible that lung cancer may be obscured or missed on your lung CT scan. In these cases, your results may indicate that you don't have lung cancer when you actually do.
  • Finding other health problems. People who smoke for a long time have an increased risk of other health problems, including lung and heart conditions that may be detected on a lung CT scan. If your doctor finds another health problem, you'll likely undergo further testing and, possibly, invasive treatments.

To prepare for a low-dose CT scan, you may need to:

  • Change into a hospital gown. You may be asked to remove your shirt and change into a gown.
  • Remove any metal you're wearing. Metals can interfere with the imaging, so you may be asked to remove any metal that you might be wearing, such as jewelry, glasses, hearing aids and dentures.

During the lung CT scan

During a low-dose CT scan of the lungs, you lie on your back on a long table. You may be given a pillow to make you more comfortable. Straps may be placed on your body to keep you still and hold you in the proper position.

The technologist who runs your scan will move to a separate room where he or she can still see you and talk with you.

You'll be asked to lie very still as the table slides through the center of a large machine that creates the images of your lungs. The table passes through the machine initially to determine the starting point for the scan.

When the machine is ready to start the scan, you may be asked to hold your breath briefly in order to create a clear picture of your lungs. The table will move slowly through the machine as the images are created. The machine may make knocking or clicking noises.

Expect your appointment to last about a half hour, though the actual scan takes less than a minute.

After the lung CT scan

When your low-dose CT scan is complete, you can change back into your clothes and go about your day.

The images created during the scan are compiled by a computer and reviewed by a doctor who specializes in diagnosing and treating diseases and conditions with imaging tests (radiologist).

A radiologist analyzes your CT scan images and sends the results to your doctor. The radiologist looks for abnormalities that might indicate a lung cancer.

Examples of lung CT scan results include:

  • No abnormalities discovered. If no abnormalities are discovered on your lung CT scan, your doctor may recommend you undergo another scan in a year. You may continue annual scans until you and your doctor determine they no longer offer benefit.
  • Lung nodules. Lung cancer may appear as one or more small spots in the lungs. Unfortunately, many other lung conditions look the same, including scars from lung infections and noncancerous (benign) growths.

    Your doctor may recommend another lung CT scan in a few months to see if the lung nodule grows. Rapidly growing nodules are more likely to be cancerous.

    A very large nodule may also be more likely to be cancerous. For that reason, your doctor may recommend additional tests, such as a procedure (biopsy) to remove a piece of a very large nodule for laboratory testing.

  • Other health problems. Your lung CT scan may detect other lung and heart problems that are common in people who have smoked for a long time, such as emphysema and hardening of the arteries in the heart. Your doctor may recommend additional tests depending on the condition.


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