Key Lung Cancer Screening Trials
The pivotal randomized controlled trials that established the evidence for low-dose CT lung cancer screening.
The Science Behind Screening
These large-scale clinical trials provided the definitive evidence that LDCT screening reduces lung cancer deaths.
National Lung Screening Trial (NLST)
The NLST was the first large-scale randomized trial to demonstrate that LDCT screening reduces lung cancer mortality. Conducted across 33 U.S. medical centers, it enrolled 53,454 current and former heavy smokers aged 55–74.
Participants were randomized to receive either three annual LDCT scans or chest X-rays. The trial found a 20% reduction in lung cancer mortality and a 6.7% reduction in all-cause mortality in the LDCT group. Published in the New England Journal of Medicine in 2011, the NLST formed the primary basis for USPSTF screening recommendations.
Participants enrolled
Mortality reduction
NELSON Trial
The Dutch-Belgian NELSON trial was the largest European randomized lung cancer screening trial, enrolling 15,792 participants aged 50–74. Unlike the NLST, it used volumetric CT assessment (measuring the three-dimensional volume of detected nodules) to determine follow-up protocols.
At 10 years, NELSON found a 24% relative reduction in lung cancer mortality among men in the screening group. The smaller female subgroup had an estimated 33% reduction, but its confidence interval included no benefit (rate ratio 0.67; 95% CI, 0.38–1.14). Published in the New England Journal of Medicine in 2020, the trial strengthened the evidence for LDCT screening.
Participants enrolled
Relative lung cancer mortality reduction in men
Sources: NLST: National Cancer Institute · NELSON primary publication.
Other Notable Screening Trials
Italy
ITALUNG
The Italian ITALUNG trial enrolled 3,206 participants and compared LDCT screening with usual care. Its follow-up contributed evidence on lung cancer mortality and the practical delivery of screening.
Denmark
DLCST
The Danish Lung Cancer Screening Trial enrolled 4,104 participants from 2004–2015. While it did not show a statistically significant mortality reduction overall, it provided important data on screening interval optimization.
Germany
LUSI
The Lung Cancer Screening Intervention Trial enrolled 4,052 participants in Germany. It evaluated LDCT screening and reported mortality outcomes, including analyses by sex. Subgroup findings should be interpreted alongside the overall result and statistical uncertainty.
UK
UKLS
The UK Lung Cancer Screening Trial used a risk-prediction model (LLPv2) rather than pack-year criteria alone to identify eligible participants, offering insights into risk-based screening strategies.
France
DEPISCAN
This French feasibility study assessed the technical and organizational aspects of implementing LDCT screening in the French healthcare system, contributing to European policy discussions.
Multi-Country
I-ELCAP
The International Early Lung Cancer Action Program is an ongoing, non-randomized screening initiative across multiple countries that has contributed extensive data on screening protocols and management algorithms.