Lung cancer screening guidelines advise older adults who are current or former smokers to undergo the screening test every year. Early detection will make a tumor easier to treat.

Screening for lung cancer refers to testing someone without symptoms or a family history of the disease. The Centers for Disease Control and Prevention (CDC) advise using low-dose computed tomography (LDCT) for lung cancer screening.

Keep reading to learn about who should undergo screening, as well as the risks and benefits of the test.

A lung scan imageShare on Pinterest
BSIP/UIG via Getty Images

A 2017 study in Medical Clinics of North America highlights lung cancer as the leading cause of cancer death in the United States. The CDC recommend lung cancer screening with LDCT for anyone who meets all of the following criteria:

  • aged 55 to 80 years
  • a history of heavy smoking
  • currently smokes or has quit within the past 15 years

Heavy smoking refers to a smoking history of 30 pack years. In a pack year, a person smokes at least an average of one pack of cigarettes per day for a year.

For example, someone with 30 pack years could have smoked one pack of cigarettes per day for 30 years or two packs per day for 15 years.

Any individual who meets the three criteria should have the screening once a year, according to the Prevention Services Task Force.

They advise people to stop yearly screenings if they:

  • turn 81 years old
  • have not smoked in at least 15 years
  • develop a condition that greatly limits their life expectancy or prevents surgery for lung cancer

The American Cancer Society (ACS) state that the main benefit of screening is the lower likelihood of death from lung cancer.

Many people will not experience symptoms of lung cancer until the disease advances. Some people may even mistake the early symptoms for those of another condition.

Someone with a higher risk of lung cancer should have yearly screenings to catch the disease in its early stages, when it is easier to treat.

However, screenings can still miss some types of lung cancer or only detect the condition at a later stage.

The National Cancer Institute (NCI) highlight some risks of regular lung cancer screening:

  • Overdiagnosis: This term describes the diagnosis and treatment of cancer that may never have caused symptoms.
  • False negatives: A false-negative test is one that fails to detect a case of lung cancer and could, as a result, delay treatment.
  • False positives: A false-positive result indicates lung cancer where it is not present, causing unnecessary concern.
  • Radiation: Regular, high doses of radiation from chest X-rays and CT scans can damage cells and increase the risk of cancer.

Doctors will weigh these possible risks against the benefits of screening in each case.

Doctors will order more testing if the screening shows abnormal results. The ACS note that in many cases, additional testing will reveal that the abnormalities are not cancer. However, the tests are still necessary as a precaution.

Doctors will use one or more imaging tests to examine the suspicious area more closely, including:

  • Chest X-rays: These are usually the first tests that doctors order.
  • CT scans: These scans show a detailed cross-section of the body and are more accurate than X-rays in detecting tumors.
  • MRI scans: MRI scans provide a detailed picture of soft tissue in the body and are useful for checking the spread of cancer.
  • PET scans: These scans involve the injection of low level radioactive sugars that can highlight cancer cells.
  • Bone scans: Bone scans also use a low level radioactive material to highlight cancer cells that have spread to the bones.

If imaging tests also suggest cancer, doctors will confirm the diagnosis by examining lung cells in a lab. They will remove the cells from lung fluids or tissues.

Treatment options for lung cancer include:

  • chemotherapy, a type of medication that kills or shrinks tumors
  • radiation therapy, which uses high energy X-rays to kill cancer cells
  • targeted therapy, involving a selection of drugs that stop cancer from spreading
  • surgery, which is sometimes an option to remove a tumor

The CDC suggest several steps that people can take to lower their risk of lung cancer. These include:

  • avoiding smoking, which they say is responsible for 80–90% of lung cancer deaths in the U.S.
  • avoiding secondhand smoke, which can cause cancer in nonsmokers
  • testing the home for signs of radon
  • reducing exposure to carcinogens at work, where possible

Lung cancer screening guidelines recommend that adults aged 55 to 80 years take the test if they smoke or have a history of heavy smoking.

Screening can reduce the likelihood of death from lung cancer, but it also includes some risks. A doctor will weigh the risks and benefits of screening in each case.

Avoiding or quitting smoking is the most important action a person can take to lower their risk of lung cancer.