Lung Cancer Screening

Lung cancer is the leading cause of cancer-related death in the United States, with 90% of cases being fatal. The vast majority of cases are associated with smoking, and thus smoking cessation is encouraged to reduce a patient’s lifetime risk. Annual screening with low-dose computed tomography is recommended for early detection in patients 50–80 years of age with a significant smoking history. This screening program has been shown to significantly reduce mortality.

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Lung cancer

Lung cancer is a malignant tumor of the lung originating from the respiratory epithelium of the bronchi, bronchioles, and alveoli.


  • Lung cancer is the leading cause of cancer-related death in the United States.
    • 90% of cases are fatal.
    • 5-year survival in approximately 18% of cases (even with advances in treatment)
    • Annual deaths:
      • 160,000 in the United States
      • 1.6 million worldwide
  • 230,000 new cases are reported annually in the United States.
    • Accounts for 13% of all cancer cases
  • Incidence increases with age:
    • Rare under the age of 50 years
    • Incidence peaks at ages 75–79 years.
  • 85%‒90% of lung cancer cases are attributed to smoking.

Risk factors

  • Smoking (most common):
    • Increased risk related to the number of cigarettes smoked, in pack-years (py) (py = number of cigarettes smoked daily x number of years smoked) / 20.
    • Smoking at a lower intensity for a long time: more likely to develop lung cancer than smoking at a higher intensity for a shorter time
    • The association with electronic cigarettes is not yet clear.
  • Environmental exposures:
    • 2nd-hand smoke
    • Air pollution
    • Asbestos
    • Radon
    • Chromium
    • Nickel
    • Arsenic
    • Polycyclic aromatic hydrocarbons
  • Radiation treatment
  • Lung disease:
    • Idiopathic pulmonary fibrosis
    • Alpha-1 antitrypsin deficiency
    • Chronic obstructive pulmonary disease (COPD)
  • Human immunodeficiency virus (HIV) infection
  • Family history
  • Alcohol consumption

Risk factor reduction

Smoking cessation reduces the risk of lung cancer.

  • Most important factor
  • The greatest benefit is seen in those who quit by age 30.
  • 39% lower risk 5 years after quitting (after a median history of 21 py)
  • 41% of the lung cancers in former smokers occur 15 years after quitting.
  • Dietary changes may be of benefit (not well established).
  • Quitting smoking also lowers the risk for other diseases/conditions (such as other cancers, atherosclerosis, and chronic obstructive pulmonary disease).

Screening Rationale

Benefits of screening

  • Goal is to detect early disease, which is:
    • More amenable to treatment
    • Associated with better prognosis
  • Several studies also show a favorable association with smoking cessation.

Risks of screening

  • High false-positive rate
  • Most abnormalities detected are benign nodules.
  • Leads to unnecessary biopsy or surgery
  • Increased radiation exposure
  • Overdiagnosis: 
    • Detection of cancers that would not have affected morbidity or mortality for the patient
    • Leads to unnecessary aggressive management 
  • Mental distress

Screening Recommendation

  • Annual low-dose computed tomography (LDCT)
  • Patient selection based on organization recommendations:
    • The United States Preventive Services Task Force (USPSTF) 2020 recommends lung cancer screening for (must meet all criteria):
      • Adults aged 50‒80 years
      • Those with a 20-py smoking history
      • Current smoker or has quit within the past 15 years
    • The American Cancer Society recommends screening for (must meet all criteria):
      • Adults aged 55‒74 years
      • 30-py smoking history
      • Current smoker or quit within the past 15 years
    • Other organizations have similar recommendations, although the age range varies.
  • All patients in a screening program should receive smoking-cessation interventions.
  • Screening can be discontinued if the patient: 
    • Has not smoked for 15 years
    • Develops a health condition that will limit life expectancy
    • Is unable or unwilling to have curative lung surgery

Related videos

Strategies for Screening

Low-dose computed tomography

  • Demonstrated reduction in mortality in the National Lung Screening Trial (NLST):
    • 20% reduction in lung cancer mortality
    • 6.7% reduction in all-cause mortality
  • LDCT produces high-resolution images with less radiation.
  • Abnormal findings should be followed up with diagnostic computed tomography (CT).
  • Lung CT screening reporting and data system (Lung-RADS®)
    • Standardized-result reporting system
    • Designed to minimize the false-positive rate
Table: Summary of LDCT finding categories and guidance
0IncompleteAwaiting prior CT images or images were technically inadequate
1Negative (no lung nodules)Continue normal annual screening.
2Benign-appearing nodule(s)Continue normal screening.
3Probably benign nodule(s)Repeat LDCT in 6 months.
4SuspiciousVaries and includes short-term follow-up LDCT, diagnostic CT, positron emission tomography, biopsy, or surgery

Chest radiograph

  • Previously used in combination with sputum cytology
  • Did not provide a mortality benefit
  • No longer recommended


  1. Deffebach, M.E., and Humphrey, L. (2020). Screening for lung cancer. UpToDate. Retrieved December 15, 2020, from
  2. Midthun, David E., MD (2020). Clinical manifestations of lung cancer. UpToDate. Retrieved December 15, 2020, from
  3. McKee, B.J. (2019). Lung-RADS standardized reporting for low-dose computed tomography for lung cancer screening. UpToDate. Retrieved December 15, 2020, from
  4. Keith, R.L. (2020). Lung carcinoma. MSD Manual Professional Version.
  5. U.S. Preventive Services Task Force. (2020). Screening for lung cancer: U.S. Preventive Services Task Force draft recommendation statement.
  6. Siddiqui, F., and Siddiqui, A.H. (2020). Lung cancer. StatPearls.
  7. Tindle, H. A., Stevenson Duncan, M., Greevy, R. A., Vasan, R. S., Kundu, S., Massion, P. P., & Freiberg, M. S. (2018). Lifetime smoking history and risk of lung cancer: Results from the framingham heart study. JNCI: Journal of the National Cancer Institute, 110(11), 1201–1207.
  8. Markaki, M., Tsamardinos, I., Langhammer, A. et al. (2018). A Validated Clinical Risk Prediction Model for Lung Cancer in Smokers of All Ages and Exposure Types: A HUNT Study. / EBioMedicine, 31(2018), 36–46.
  9. Pleasants, R.A, Rivera, M.P., Tilley, S.L., Bhatt, S.P. (2020). Both Duration and Pack-Years of Tobacco Smoking Should Be Used for Clinical Practice and Research. Annals of the American Thoracic Society, 17(7), 804–806. 
  10. ELF. Lung cancer. Retrieved December 15, 2020, from
  11. CDC. (2020). Smoking and Cancer.
  12. Kumar, V., Abbas, A. K., Aster, J.C., (Eds.) (2020). Effects of Tobacco. Robbins & Cotran Pathologic Basis of Disease. (10 ed. pp. 415–418).

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