Who Should Be Screened for Lung Cancer?

man talks to his doctor in office

A harsh truth about lung cancer is that it doesn’t usually cause symptoms until the cancer has spread, which makes it difficult to treat. That’s why the idea of screening – looking for lung cancer in people who do not have any symptoms – is appealing. It has the potential to find the cancer earlier, when it might be easier to treat.

But screening carries risks that may outweigh the benefits for most people. The people who are most likely to benefit from screening are those at higher risk for lung cancer, such as people with a long history of smoking.

How lung screening works

A test known as low-dose CAT scan or CT scan (LDCT) has been studied in people at a higher risk of getting lung cancer. LDCT scans can help find abnormal areas in the lungs that may be cancer. Research has shown that using LDCT scans to screen people at higher risk of lung cancer saved more lives compared to chest x-rays. For higher risk people, getting yearly LDCT scans before symptoms start helps lower the risk of dying from lung cancer.

To weigh the benefits and risks before issuing current guidelines, experts at the American Cancer Society reviewed several studies that looked at low-dose CT screening. The most significant was the National Lung Screening Trial (NLST). This study included more than 50,000 people aged 55 to 74 who were current or former smokers with at least a 30 pack-year history of smoking (equal to smoking a pack a day for 30 years, or 2 packs a day for 15 years) and who had quit in the 15 years prior to the study. The study found that people
who got LDCT had a 20% lower chance of dying from lung cancer than those who got chest x-rays. However, some other trials have not found a benefit from screening.

The screening in the NLST was done at large teaching hospitals with access to medical specialists and comprehensive follow-up care. Most were National Cancer Institute cancer centers.

None of the studies included people who never smoked. Although non-smokers can develop lung cancer, there is not enough evidence to know whether screening them would be helpful or harmful. Likewise, it is not known if screening would help people who were lighter smokers than those in the studies, or those of different ages. That’s why the American Cancer Society guideline doesn’t recommend screening for these groups.

High-risk patients should consider getting screened

There are risks associated with low-dose CT scanning, and the possibility of doing more harm than good for people who are less likely to have lung cancer. Because of this, the American Cancer Society recommends people who are at highter risk for lung cancer talk to their doctor who can help them make an informed decision about whether to get screened. If people do decide to get screened, they should get screened every year through age 74, as long as they are still healthy.

One drawback of this test is that it also finds a lot of abnormalities that have to be checked out with more tests, but that turn out not to be cancer. (About 1 out of 4 people in the NLST had such a finding.) This may lead to additional tests such as other CT scans or more invasive tests such as needle biopsies or even surgery to remove a portion of lung in some people. These tests can sometimes lead to complications (like a collapsed lung) or rarely, death, even in people who do not have cancer (or who have very early stage cancer).

LDCTs also exposes people to a small amount of radiation with each test. It is less than the dose from a standard CT, but it is more than the dose from a chest x-ray. Some people who are screened may end up needing further CT scans, which means more radiation exposure. When done in tens of thousands of people, this radiation may cause a few people to develop breast, lung, or thyroid cancers later on.

American Cancer Society Guideline

The American Cancer Society recommends yearly lung cancer screening with LDCT scans for people who are 55 to 74 years old, are in fairly good health, and who also meet the following conditions:

  • Are current smokers or smokers who have quit in the past 15 years.

        and

  • Have at least a 30 pack-year smoking history. (This is the number of years you smoked multiplied by the number of packs of cigarettes per day. For example, someone who smoked 2 packs per day for 15 years [2 x 15 = 30] has 30 pack-years of smoking. A person who smoked 1 pack per day for 30 years [1x 30 = 30] also has 30 pack-years of smoking.)

        and

  • Receive counseling to quit smoking if they are current smokers.

        and

  • Have been told by their doctor about the possible benefits, limits, and harms of screening with LDCT scans.

        and


  • Have a facility where they can go that has experience in lung cancer screening and treatment.

Medicare covers screening

The Centers for Medicare and Medicaid Services (CMS) decided low-dose CT will be reimbursed once a year for Medicare patients who are eligible for lung cancer screening. People must be 55 to 77 years old, have at least a 30 pack-year history of smoking, and currently smoke or have quit within the past 15 years.

Because lung screening is recommended by the US Preventive Services Task Force (USPSTF), private insurers have also begun covering the tests. However, the criteria for screening eligibility are slightly different. For example, USPSTF guidelines call for screening up to age 80.

Quitting is still best

Screening is not a substitute for quitting smoking. The most effective way to lower lung cancer risk is to stay away from tobacco.

Signs and symptoms of lung cancer

Although it is not common, lung cancer sometimes causes symptoms in the early stages. Most of the symptoms are more likely to be caused by something that isn’t lung cancer. But it’s important to go to the doctor so the cause can be found and treated. And if it does turn out to be lung cancer, it might be diagnosed at an earlier stage, when treatment is more likely to be effective.

The most common symptoms of lung cancer are:

  • A cough that does not go away or gets worse
  • Chest pain that is often worse with deep breathing, coughing, or laughing
  • Hoarseness
  • Unexplained weight loss and loss of appetite
  • Coughing up blood or rust-colored sputum (spit or phlegm)
  • Shortness of breath
  • Feeling tired or weak
  • Infections such as bronchitis and pneumonia that don’t go away or keep coming back
  • New onset of wheezing

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.


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