Lung Cancer Screening Guidelines for Current or Former Smokers

American Cancer Society guidelines recommend yearly lung cancer screening for people who meet certain criteria that put them at higher risk for developing the disease. These higher risk patients are aged 55 to 74 years and are in fairly good health, currently smoke or have quit within the past 15 years, and have a smoking history equivalent to a pack a day for 30 years.

For these higher risk patients, the recommendations also say they need to:

• receive smoking cessation counseling if they are still smoking.
• be involved in shared decision-making about the benefits, limitations, and harms of screening.
• have access to a high-volume, high-quality lung cancer screening and treatment center.

If people decide to be screened, the recommendation specifies that testing be done with a low dose computed tomography (LDCT) scan and take place at a facility with experience in lung cancer screening. And it emphasizes that screening is not a substitute for quitting smoking. The most effective way to lower lung cancer risk is to stay away from tobacco.

The most recent guidelines were published May 30, 2018 in CA: A Cancer Journal for Clinicians.

Evidence backs guidelines

The recommendations are based on a careful review of several studies that looked at LDCT 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). The NLST found that people who got LDCT had a 20% lower chance of dying from lung cancer than those who got chest x-rays. However, other trials found no benefit from screening.

The screening in the NLST was done at large teaching hospitals with access to a lot of 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 guideline doesn’t recommend screening for these groups.

Weighing risks and benefits

The idea of screening for lung cancer is appealing, because it has the potential of finding the cancer earlier, when it might be easier to treat. Screening is done in people who do not have any symptoms of cancer. Lung cancer symptoms don’t usually appear until the cancer is already advanced and not able to be cured. But screening carries risks that may outweigh the benefits for everyone except those at higher than average risk for lung cancer, often heavy smokers. Advancing age is also a risk factor.

One drawback of a LDCT scan is that it finds a lot of abnormalities that turn out not to be cancer but that still need to be assessed to be sure. (About 1 out of 4 people in the NLST had such a finding.) This may lead to additional scans or even more-invasive tests such as needle biopsies or even surgery to remove a portion of lung in some people. A small number of people who do not have cancer or have very early stage cancer have died from these tests. There is also a risk that comes with increased exposure to radiation from the LDCT scan.

Because of these risks, screening with LDCT is not recommended for people who do not meet the criteria in the guidelines. LDCT is also not recommended for people who have other serious diseases that may limit their life expectancy. The guidelines say people at higher risk for lung cancer should discuss with their doctors all the potential risks, benefits, and limitations of screening to help them make an informed decision about whether they should 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.

Screening should only be done at facilities that have the right type of LDCT scan and that have a great deal of experience in LDCT scans for lung cancer screening. The facility should also have a team of specialists who can provide the appropriate care and follow-up of patients with abnormal results on the scans.

Quitting is still best

The recommendations emphasize that screening for lung cancer is not a substitute for quitting smoking. The most important thing anyone can do to reduce their risk of lung cancer is not smoke or use any form of tobacco. Although not all lung cancers are caused by smoking, about 80% of all lung cancer deaths are thought to result from smoking.

Besides lung cancer, tobacco use also increases the risk for cancers of the mouth, lips, voice box, throat, esophagus, stomach, pancreas, kidney, bladder, cervix, colon/rectum, and myeloid leukemia.

If you smoke and want help quitting, see the American Cancer Society Guide to Quitting Tobacco or call us at 1-800-227-2345.