Evidence of Benefit Associated With Screening

Screening by low-dose helical computed tomography

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.

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

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.

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]

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