Will lung CT scans help doctors diagnose lung cancer earlier?

Prior lung CT scan studies have shown that screening increases detection of early-stage cancer, and the NLST results provide evidence that those diagnoses end up being more beneficial than harmful in that they reduce the likelihood of death.

Being diagnosed with lung cancer at an earlier stage does make it more likely that surgery — the best treatment for most types of lung cancer — can remove and cure the cancer.

What are the risks of lung CT scans?

Risks of lung CT scans can include:

  • Finding abnormalities that are eventually determined to not be cancer. CT scans find abnormalities in about 20 to 60 percent of smokers and former smokers, but most of these abnormalities are scars from inflammation or other noncancerous conditions. The CT scan's sensitivity can result in doctors suspecting the possibility of cancer where there really is no cancer, which results in invasive follow-up tests, unnecessary surgery, and anxiety for those getting screened and their loved ones. In other words, screening leads to necessary invasive tests and surgery for lung cancer, but these tests end up being unnecessary if it's eventually determined that the spot first found on a CT scan isn't lung cancer but instead something benign.
  • Finding very small abnormalities that require follow-up scans. CT scans are so good at seeing nodules or spots on the lung that they can see very small nodules that don't need immediate testing, but do need follow-up CT scanning to detect any changes.
  • Exposure to radiation. CT scans expose you to a small dose of radiation. Compared with some other parts of the body, such as the breast, lungs have greater potential for developing radiation-induced cancer. Several studies have estimated an increased risk of developing cancer from CT scan radiation. The risk of developing cancers from CT scans is small, but it's a reminder of the importance of weighing the risk vs. the benefit of any medical test.

What will you tell patients who ask about lung CT scans?

Currently, these major medical organizations — the National Comprehensive Cancer Network, the American College of Chest Physicians, the American Society of Clinical Oncology and the American Cancer Society — recommend screening for lung cancer for certain individuals. There is much to be learned about who may benefit from lung CT scan screening and who may not benefit. Until then, it's best to discuss the potential benefits and risks of lung CT scan screening with your doctor. Despite the news about the potential benefits of lung CT scan screening, it's still important to remain focused on risk reduction in trying to keep people from starting smoking and getting smokers to stop smoking.

Feb. 27, 2013 See more In-depth