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Lung Cancer Screening (PDQ®)

Health Professional Version

Overview

Separate PDQ summaries on Lung Cancer Prevention, Small Cell Lung Cancer Treatment, Non-Small Cell Lung Cancer Treatment, and Levels of Evidence for Cancer Screening and Prevention Studies are also available.

Evidence of Benefit Associated With Screening

Screening by low-dose helical computed tomography

Benefits

There is evidence that screening persons aged 55 to 74 years who have cigarette smoking histories of 30 or more pack-years and who, if they are former smokers, have quit within the last 15 years reduces lung cancer mortality by 20% and all-cause mortality by 6.7%.

Magnitude of Effect: 16% relative reduction in lung cancer–specific mortality.

  • Study Design: Evidence obtained from a randomized controlled trial.
  • Internal Validity: Good.
  • Consistency: Not applicable (N/A)—one randomized trial to date.
  • External Validity: Fair.
Harms

Based on solid evidence, at least 98% of all positive low-dose helical computed tomography screening exams (but not all) do not result in a lung cancer diagnosis. False-positive exams may result in unnecessary invasive diagnostic procedures.

Magnitude of Effect: Large.

  • Study Design: Evidence obtained from a randomized controlled trial.
  • Internal Validity: Good.
  • Consistency: Good.
  • External Validity: Fair.

Evidence of No Benefit Associated With Screening

Screening by chest x-ray and/or sputum cytology

Benefits

Based on solid evidence, screening with chest x-ray and/or sputum cytology does not reduce mortality from lung cancer in the general population or in ever-smokers.

Magnitude of Effect: N/A.

  • Study Design: Randomized controlled trials.
  • Internal Validity: Good.
  • Consistency: Good.
  • External Validity: Good.
Harms
False positive exams

Based on solid evidence, at least 95% of all positive chest x-ray screening exams (but not all) do not result in a lung cancer diagnosis. False-positive exams result in unnecessary invasive diagnostic procedures.

  • Study Design: Randomized controlled trials.
  • Internal Validity: Good.
  • Consistency: Good.
  • External Validity: Good.
Overdiagnosis

Based on solid evidence, a modest but non-negligible percentage of lung cancers detected by screening chest x-ray and/or sputum cytology appear to represent overdiagnosed cancer; the magnitude of overdiagnosis appears to be between 5% and 25%. These cancers result in unnecessary diagnostic procedures and also lead to unnecessary treatment. Harms of diagnostic procedures and treatment occur most frequently among long-term and/or heavy smokers because of smoking-associated comorbidities that increase risk propagation.

Magnitude of Effect: Between 5% and 25%, depending on characteristics of screened population and screening regimen.

  • Study Design: Randomized controlled trials.
  • Internal Validity: Good.
  • Consistency: Good.
  • External Validity: Good.
  • Updated: April 24, 2015