Lung cancer screening: A number of organizations now recommend lung cancer screening with low-dose CT scans in heavy smokers who meet certain criteria (see lung cancer screening recommendations). In the past, annual chest X-rays have been studied as a screening tool for lung cancer. Chest X-ray screening has not been found to decrease lung cancer mortality. In 2011, results from the National Lung Screening Trial (NLST) were published. The NLST was an enormous, randomized controlled trial (53,454 subjects) that compared annual screening with low-dose CT scan to annual screening with chest X-ray in heavy smokers. The trial showed that low-dose CT scan screening reduced lung cancer mortality and overall mortality compared to chest X-ray screening. Since the publication of the NLST trial, the American Cancer Society, the American Lung Association, the National Comprehensive Cancer Network, the American College of Chest Physicians, and the USPSTF have all made recommendations in favor of lung cancer screening based on the NLST results.

NLST - Annual Low-Dose CT Scan vs Annual Chest X-Ray for Lung Cancer Mortality in Heavy Smokers, NEJM (2011) [Pubmed Abstract]
  • The NLST enrolled 53,454 smokers
Main inclusion criteria
  • Age between 55 - 74 years
  • Smoking history ≥ 30 pack-years
  • If former smoker, quit within the last 15 years
Main exclusion criteria
  • History of lung cancer
  • Hemoptysis
  • Unexplained weight loss
Baseline characteristics
  • Average age 61.4 years
  • Male sex - 59%
  • Median cigarette history - 48 pack-years
  • Median duration of smoking - 43 years
  • Current smoker - 48%
Randomized treatment groups
  • Group 1 (26,722 patients) - Annual lung cancer screening with low-dose CT scan
  • Group 2 (26,732 patients) - Annual chest X-ray
Primary outcome: Death from lung cancer

Duration: Median of 6.5 years
Outcome CT scan Chest X-ray Comparisons
Primary outcome 1.33% 1.66% p=0.004
Overall mortality 7.02% 7.48% p=0.02
Lung cancer diagnosis 3.96% 3.52% p>0.05
False-positive rate 96.4% 94.5% N/A
Adherence 95% 93% N/A
  • In the CT scan group, 39% of participants had at least one positive screening test. In the chest X-ray group, 16% of participants had at least one positive screening test.

Findings: Screening with the use of low-dose CT reduces mortality from lung cancer

1 - ACS GL
2 - JAMA review - PMID 23512063
3 - BMJ study - PMID 10926586
4 - NLST study PubMed Abstract