New Lung Cancer Screening Guidelines for Heavy SmokersJan 11, 2013
The American Cancer Society has published new guidelines that recommend doctors discuss lung cancer screening with people who meet certain criteria that put them at high risk for developing the disease. These high risk patients must be aged 55 to 74 years and in fairly good health, have a smoking history equivalent to a pack a day for 30 years, and currently smoke or have quit within the past 15 years.
If people decide to be screened, the recommendation specifies that testing should be done with a low dose computed tomography (CT) 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 guidelines were published early online January 11, 2013 in CA: A Cancer Journal for Clinicians.
Evidence backs guidelines
The recommendations are based on a careful review of 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). The NLST found that people who got low-dose CT 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’s 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. Age is also a risk factor.
One drawback of a low-dose CT 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.
Because of these risks, CT scanning is not recommended for people who are less heavy smokers, or who are younger than 55 or older than 74. It is not recommended for people who have other serious diseases that limit their life expectancy. The guidelines say doctors need to discuss all the potential risks, benefits, and limitations of screening with patients who meet the criteria and 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 CT 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 that 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. Most lung cancer cases occur in people who smoke or used to smoke.
Besides lung cancer, tobacco use also increases the risk for cancers of the mouth, lips, nose and sinuses, voice box, throat, esophagus, stomach, pancreas, kidney, bladder, uterus, cervix, colon/rectum, ovary, and acute myeloid leukemia. In the US, tobacco use is responsible for nearly 1 in 5 deaths; this equals about 443,000 early deaths each year.
If you smoke and want help quitting, see the American Cancer Society Guide to Quitting Smoking or call us at 1-800-227-2345.
American Cancer Society Lung Cancer Screening Guidelines. Published early online January 11, 2013 in CA: A Cancer Journal for Clinicians. First author: Richard Wender, MD, Thomas Jefferson University Medical College, Philadelphia.