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National Lung Screening Trial (NLST)


NLST results showed that participant compliance with screening was over 90 percent. Lung cancer incidence per 100,000 person-years was 645 (1,060 cancers) in the low-dose helical CT arm and 572 (941 cancers) in the chest X-ray arm. Lung cancer mortality was 247 per 100,000 person-years in the low-dose helical CT arm and 309 in the chest X-ray arm, representing a reduction in lung cancer mortality in the low-dose helical CT arm of 20.0 percent.  All-cause mortality (deaths due to any cause, including lung cancer) was reduced by 6.7 percent for those participants who underwent low-dose helical CTs compared to those who got chest X-rays, although this was largely due to the reduction in lung cancer deaths.

Main ObjectiveNLST compared two ways of detecting lung cancer: low-dose helical computed tomography (CT) and standard chest X-ray, to see if CT screening could reduce lung cancer specific mortality relative to chest X-ray.
Enrollment Accrual PeriodAugust 2002 to April  2004
ParticipantsA total of 53,454 participants, with approximately equal ethnic distribution between the two arms:
  • 90.8% white
  • 4.4% African American
  • 1.7% Hispanic/Latino
  • 2.0% Asian
InterventionParticipants were randomized to 3 annual screens with either low-dose helical CT or single-view chest X-ray
Criteria for Participation
  • 55 to 74 years of age
  • Cigarette smoking history of at least 30 pack-years
  • Former smokers must have quit within the past 15 years.
Study SitesTwo sets of centers: Lung Screening Study sites had 10 coordinating sites and 25 satellite sites and American College of Radiology Imaging Network hosted 23 sites.