Finding lung cancer early, when it is easiest to treat, can save lives. Currently, only 16% of lung cancers are diagnosed while the tumor is still in its earliest 1of growth (localized).
One of the challenges for finding lung cancer early is that most people with lung cancers only have symptoms when they are in later stages of disease. Screening for lung cancer means using tests or exams to look for cancer before a person has any symptoms of the disease.
Another challenge has been that conventionaloften miss early-stage lung cancers.
High-resolution, which is much more sensitive, is now recommended for early detection in high-risk individuals.
But many people who develop lung cancer do not fit the high-risk profile, like never-smokers, people under the age of 55, or people who quit smoking a long time ago.
The ultimate goal is to develop a reliable and broadly available test for lung cancer that can catch the disease early even in people not considered high-risk.
Who should be screened for lung cancer?
Guidelines for lung cancer screening have been established by the US Preventive Services Task Force (USPSTF) using the results from the.
The recommendations include yearly screening with low-dose CT scans in adults who:
- Are aged 55 to 80 years and
- Have a 30 pack-year smoking history (the number of cigarette packs smoked a day multiplied by the number of years a person smoked) and
- Currently smoke or have quit within the past 15 years2
The US Preventive Services Task Force recommends that lung cancer screening stop once a person:
- Reaches 81 years of age or
- Has not smoked in 15 years or
- Develops a health problem that makes him or her unable or not willing to have surgery if lung cancer is diagnosed2
The National Lung Screening Trial (NLST)
The National Lung Screening Trial (NLST) was funded by the National Institutes of Health (NIH). It looked at using a(also called low-dose spiral CT or helical CT scan) to screen for lung cancer. Over 53,000 current and former heavy smokers aged 55 to 74 participated at 33 sites across the United States. Starting in August 2002, subjects remained in the trial for a 20-month period and were randomly assigned to receive three annual screens with either a low-dose CT scan or a standard chest X-ray.
The study found that people who were screened with a low-dose CT scan had a 20% lower chance of dying of lung cancer than those who were screened with a chest X-ray.3
How is screening done?
For lung cancer screening today, low-dose spiral (or helical) computed tomography (CT) is used.4 This imaging procedure uses a computer linked to special X-ray equipment to create detailed pictures, or scans, of areas inside the body from different angles. The scans can show both two-dimensional and three-dimensional images of anything abnormal in the chest.
During a CT procedure, the person lies very still on a table, and the table passes slowly through the center of the scanner. With some types of CT scanners, the table stays still and the machine moves around the person. The person might hear whirring sounds during the procedure. At times during a CT procedure, the person will be asked to hold his or her breath to prevent blurring of the images. For lung cancer screening, the procedure usually only takes a few minutes.
A CT scan can give very detailed information, including the size, shape, or location of the abnormality. A scan cannot tell you whether that abnormality is cancer or not.
What else should you know about screening?
Although low-dose CT scans are a promising option in lung cancer screening, they do have some drawbacks, including that they:
- Find many abnormalities that look like small lung nodules (up to 50% of the time) that have to be checked with either another CT scan or a if considered suspicious. The vast majority of the time these end up not being cancer.
- Can miss very small cancers or cancers that are hidden behind other structures in the chest.
- Expose a person to a small amount of radiation. While it is a smaller dose than that from a standard CT scan, it often leads to further CT scans, which in turn results in greater radiation exposure. High doses of radiation exposure can lead to other types of cancer in the future.
Following are some of the factors that should be considered when a person discusses screening with his or her doctor:
- Screening with low-dose CT scans will not find every lung tumor
- Not all tumors that are found will be at an early stage
- A low-dose CT scan may find something that does not end up being cancer
- Screening can only be done at facilities that have the specific type of CT scan, so a person may have to travel to obtain screening
- Screening should be done at a facility that has a multidisciplinary group of experts for screening and for the management of lung nodules or other findings
- Not all insurance companies currently cover CT scan screening for lung cancer, although some states have passed legislation requiring coverage for people at high risk
- Screening for lung cancer goes hand in hand with smoking cessation. This is a perfect time to reconsider smoking cessation efforts and counseling
The current estimated Medicare reimbursement rate for a non-contrast helical diagnostic CT scan of the lung is $300, but this varies by geographic location.3
Choosing a screening center
[This section is adapted with permission from Lung Cancer Alliance.]
Ideally, the decision to be screened or not should be made with the help of a person's primary care doctor or pulmonologist. The doctor knows the patient's history and possible risk factors best and can help guide him or her to the right screening center.
Some screening centers require a doctor’s prescription in advance for a scan. Others will do an evaluation, also called a risk assessment, without a prescription to determine whether a person's history and risk factors warrant a scan.
We recommend getting screened at a center that:
- Provides clear information on the risks and benefits of CT screening
- Complies with standards based on best published practices for controlling screening quality, radiation dose, and diagnostic procedures. We strongly recommend the protocol developed by the National Comprehensive Cancer Network (NCCN), but at a minimum, the NLST protocol is acceptable.
- Works with a lung cancer multidisciplinary clinical team, including radiologists, pathologists, pulmonologists, thoracic surgeons, oncologists, radiation oncologists, and nurses, to carry out a coordinated process for screening, follow-up, and treatment when appropriate
- Includes a comprehensive cessation program for those still smoking or be willing to refer to comprehensive cessation programs
- Reports results to those screened and their primary care doctors and transmits requested copies in a timely manner
One resource for finding high-quality screening sites is Lung Cancer Alliance’s listing of Screening Centers of Excellence, which Lung Cancer Alliance developed together with a panel of thoracic surgeons, oncologists, and nurse navigators.
Latest research in lung cancer screening
Advances in imaging techniques, such as the low-dose CT scan, have improved the chances of finding lung cancer early. Researchers continue to look for other techniques that could help identify lung cancer at an early stage. More sensitive tests that can find lung cancer cells in sputum or blood, even before the cancer is seen on a CT scan, are being studied. In addition, biomarker testing to identify which patients have a higher risk of lung cancer is also being researched. Many medical centers, particularly academic centers, will ask their patients to participate in this research, as this is the only way to move our knowledge of this area forward.
Updated March 4, 2016.
- SEER Stat Fact Sheets: Lung and Bronchus Cancer. National Cancer Institute website. http://seer.cancer.gov/statfacts/html/lungb.html. Published April 2015. Accessed March 4, 2016.
- Screening for Lung Cancer. US Preventive Services Task Force website. http://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummary.... Published December 2013. Accessed March 4, 2016.
- National lung Screening Trial (NLST) Initial Results: Fast Facts. National Cancer Institute website. http://www.cancer.gov/news-events/press-releases/2011/nlstfastfacts. Updated June 29, 2011. Accessed March 4, 2016.
- Computed Tomography (CT) Scans and Cancer. National Cancer Institute website. http://www.cancer.gov/about-cancer/diagnosis-staging/ct-scans-fact-sheet. Reviewed July 16, 2013. Accessed March 4, 2016.