Finding lung cancer early

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When lung cancer is found and treated early, the chances of successful treatment are better. Get regular health checkups and see your doctor if you have any symptoms or are worried about your health.

Screening for smokers and former smokers

Smokers and former smokers have the highest risk of developing lung cancer. Research shows that screening with computed tomography (CT) scan using lower doses of radiation (called low-dose CT) can find lung cancer in these people before they have any symptoms. This might help lower their risk of dying from lung cancer. (Lung cancer screening using chest x-rays and sputum test is not recommended. Studies show that these tests are not effective in finding lung cancer early.)

Right now there are no provincial or territorial screening programs for lung cancer. Some provinces have begun pilot programs with the plan of starting a formal program at a later date.

The Canadian Task Force on Preventive Health Care (CTFPHC) recommends screening for lung cancer with low-dose CT once each year for 3 years in adults who:

  • are 50–74 years of age (evidence shows that screening is most effective for people in this age group)
  • are current smokers or former smokers who quit in the last 15 years
  • have smoked 30 pack-years, which is defined as 1 pack per day for at least 30 years or 2 packs per day for 15 years

CTFPHC strongly recommends that any lung cancer screening program includes support to help people quit smoking. Smoking can make many cancer treatments less effective, and smokers have a higher risk of complications and death than non-smokers. Not smoking is the best way to lower your risk of dying from lung cancer.

Benefits and risks of screening

Talk to your doctor about the benefits and risks of screening for lung cancer and if it is right for you. People who do not have high risk for lung cancer based on their smoking history should not be screened for this disease. There is not enough evidence to know if screening is effective for people who have smoked less than 30 pack-years or for people who have other risk factors for lung cancer.

It is important to remember that there could be harms from screening for lung cancer with low-dose CT scan. These include exposure to radiation, false-positive test results and complications from tests used to follow-up the CT scan results. Testing can also find a cancer that would not cause illness or death, which may lead to unnecessary treatment and side effects from these treatments.

Expert review and references

  • Aberle DR, DeMello S, Berg CD, et al . Results of the two incidence screenings in the National Lung Screening Trial. New England Journal of Medicine. 2013.
  • Canadian Task Force on Preventive Health Care . Recommendations on screening for lung cancer. CMAJ. 2016:
  • Kramer BS, Berg CD, Aberle DR, Prorok PC. . Lung cancer screening with low-dose helical CT: results from the National Lung Screening Trial (NLST). Journal of Medical Screening. RSM Press; 2011.
  • National Cancer Institute. National Lung Screening Trial: Questions and answers. 2014:
  • National Lung Screening Trial Research Team, Aberle DR, Adams AM, et al . Reduced lung-cancer mortality with low-dose computed tomographic screening. New England Journal of Medicine. Massachusetts Medical Society; 2011.
  • Radiological Society of North America. Lung cancer screening. 2013: