NLST
National Lung Screening Trial: a randomized trial comparing low-dose helical CT with chest X-ray for lung cancer
Phase 3N = 53,454NCT00047385
- Population
- People aged 55 to 74 years at randomisation with a history of cigarette smoking of at least 30 pack-years who, if former smokers, had quit within the previous 15 years. People with a previous lung cancer diagnosis, a chest CT within 18 months, haemoptysis, or unexplained weight loss of more than 6.8 kg (15 lb) in the preceding year were excluded.
- Design
- Randomised multicentre trial at 33 US medical centres (10 Lung Screening Study and 23 ACRIN centres). Participants were assigned to three annual screens (baseline, year 1, year 2) with either low-dose CT or single-view posteroanterior chest radiography. Enrolment ran from August 2002 to April 2004; events were counted through 31 December 2009. The primary analysis compared lung-cancer mortality between the two groups by the intention-to-screen principle.
- Primary endpoint
- Lung cancer mortality
- Arms
- Low-dose CT (experimental, n = 26,722): Three annual screens with low-dose CT
- Chest radiography (control, n = 26,732): Three annual screens with single-view posteroanterior chest radiography
- People
- National Lung Screening Trial Research Team, National Lung Screening Trial Research Team
Δ Positive screening test rate+17.3 pointsΔ False-positive share of positive screening results+1.9 points
Show the numbers
| Endpoint | Analysis | Low-dose CT | Chest radiography | Effect |
|---|---|---|---|---|
| Positive screening test rateAll screening tests over the three roundsProportion of screening tests classified as positive across all three rounds (counted per test, not per person). | primaryNational 2011 | 24.2% | 6.9% | Per round (full text, Results): 27.3% vs 9.2% at baseline, 27.9% vs 6.2% at year 1, 16.8% vs 5.0% at year 2. The primary mortality outcome is reported as rates per 100,000 person-years with a relative reduction, not as per-arm percentages; see the milestone figures. |
| False-positive share of positive screening resultsAll positive screening results over the three roundsProportion of positive screening results that were false positives (the abnormality was not lung cancer), across all three rounds. The paper's main text does not restate its operational definition. | primaryNational 2011 | 96.4% | 94.5% | — |
| Endpoint | Analysis | Low-dose CT | Chest radiography | Effect |
|---|---|---|---|---|
| Positive screening test rateAll screening tests over the three roundsProportion of screening tests classified as positive across all three rounds (counted per test, not per person). | primaryNational 2011 | 24.2% | 6.9% | Per round (full text, Results): 27.3% vs 9.2% at baseline, 27.9% vs 6.2% at year 1, 16.8% vs 5.0% at year 2. The primary mortality outcome is reported as rates per 100,000 person-years with a relative reduction, not as per-arm percentages; see the milestone figures. |
| False-positive share of positive screening resultsAll positive screening results over the three roundsProportion of positive screening results that were false positives (the abnormality was not lung cancer), across all three rounds. The paper's main text does not restate its operational definition. | primaryNational 2011 | 96.4% | 94.5% | — |