Should I Be Screened for Lung Cancer?
When people who have no symptoms are tested to detect a disease, that process is called “screening.”
Screening for cancer increases the chance of being diagnosed at early stages when cancer can be more successfully treated and even cured. Early stage diagnosis is associated with longer survival rates.
In lung cancer, studies have shown that the disease can be detected at an early stage using a low dose spiral CT scan. Unlike a chest x-ray which produces flat, 2-dimensional images of the lungs, a CT scanner can explore the entire volume of the lungs by taking a continuing series of x-rays in a spiral around the chest. The images taken by a CT scanner can be examined on a computer in “slices” and reconstructed in 3-dimensions giving very detailed information about the volume and shape of spots of the lung or lung nodules.
According to the National Comprehensive Cancer Network (NCCN), a professional organization that produces guidelines for diagnosis and treatment of cancer, people who fit the following criteria should be screened for lung cancer:
- Current smokers and former smokers (who quit within the past 15 years) with a 30 pack year history (number of packs a day times the number of years of smoking) who are between the ages of 55 and 74.
- Current and former smokers, ages 50 and up, with a 20 pack year history who also had one of the following additional risk factors:
- Exposure to radon;
- Exposure to occupational carcinogens, such as silica, cadmium, asbestos, arsenic, beryllium, chromium, diesel fumes and nickel;
- A previous cancer;
- A family history of lung cancer;
- COPD or pulmonary fibrosis.
If you do not fit all of this criteria but have some of these risk factors, talk to your doctor about whether it makes sense for you to consider screening. If you are a veteran and were exposed to Agent Orange or other toxins, you should also talk with your doctor about your risk for lung cancer.
It is also important to know that, as in any screening, there are risks:
- “False positive” findings: CT scanners can “see” spots on the lung as small as a grain of rice. If the scan picks up any findings suspicious for lung cancer, it is called a “positive screen.” That does not mean that the suspicious findings are definitely cancer. Many people, especially smokers or former smokers and people who live in areas where lung infections are common may have a positive screen that could be caused by inflammation, scarring or other lung diseases. Most of the time, these spots are not cancer.
- Anxiety: If cancer is suspected, additional testing will be required to confirm the results. Anxiety during this process is common.
- Risk associated with biopsy: A biopsy may be needed so that a small sample of tissue from the nodule can be examined under a microscope for cancer cells. Tissue is collected through a tube inserted down the windpipe (bronchoscopy) or with a needle through the chest wall (percutaneous fine-needle aspiration). Both procedures entail some risk of bleeding, infection or collapsed lung and should only be done by experienced doctors.
- Unnecessary surgery: Even with all these precautions, some nodules - about 0. 5% - that are not cancerous may end up being removed by unnecessary surgery. All lung surgery carries significant risk and after effects.
- Radiation exposure: Some people worry about radiation exposure from lung cancer screening. Screening scans that check people who have no symptoms for lung cancer are given at low dose, which means that the level of radiation used is very low (similar to the radiation dose in a mammogram). Follow-up scans that may have to be done to determine if any change or growth has occurred are at the same low-dose.
Many of these risks can be minimized by going to a center that screens for lung cancer in a responsible way and follows specific guidelines including those in the next section. “Where should I go to be screened?”