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Lung Cancer Screening (PDQ®)

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: 20% relative reduction in lung cancer–specific mortality.

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

Based on solid evidence, screening would lead to false-positive tests in approximately one-quarter of those screened. Most abnormalities would be monitored radiographically. However, persons with false-positive screens and overdiagnosed cancers would be exposed to unnecessary invasive diagnostic procedures and treatments. Because of comorbidities among the heaviest smokers and those who have smoked for long periods of time, complications associated with invasive diagnostic procedures and therapy may be more frequent in these groups.

Magnitude of Effect: Positive. Magnitude is a 20% relative reduction in lung cancer–specific mortality and a 6.7% reduction in overall mortality.

  • 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: No evidence of effect.

  • 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, some lung cancers detected by screening chest x-ray and/or sputum cytology appear to represent overdiagnosed cancer. Because of comorbidities, harms of diagnostic procedures and treatment may be most frequent among long-term and/or heavy smokers.

Magnitude of Effect: When calculated as the ratio of all lung cancer cases in the intervention arm to those in the control arm (percent excess cases), the magnitude of overdiagnosis ranges from 6% [1] to 17% [2].

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

References

  1. Oken MM, Hocking WG, Kvale PA, et al.: Screening by chest radiograph and lung cancer mortality: the Prostate, Lung, Colorectal, and Ovarian (PLCO) randomized trial. JAMA 306 (17): 1865-73, 2011. [PUBMED Abstract]
  2. Marcus PM, Bergstralh EJ, Zweig MH, et al.: Extended lung cancer incidence follow-up in the Mayo Lung Project and overdiagnosis. J Natl Cancer Inst 98 (11): 748-56, 2006. [PUBMED Abstract]
  • Updated: February 21, 2014