# NLST & NELSON (low-dose CT screening)

Source: https://onco.cc/trials/nlst-nelson/  
OnCo record `nlst-nelson` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The two trials that proved a yearly low-dose CT scan cuts lung cancer deaths in heavy smokers.

## Summary

NLST (NEJM 2011) showed a 20% relative reduction in lung cancer mortality with three annual low-dose CTs versus chest radiography. NELSON (NEJM 2020) showed a 24% reduction in men at 10 years with volume-based nodule management and a lower false-positive rate. Together they underpin USPSTF (age 50-80, ≥20 pack-years) and European screening recommendations. Uptake remains low.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-06
- Phase: 3
- Setting: Annual low-dose CT versus chest X-ray (NLST, 53,454 heavy smokers) or no screening (NELSON, 15,789) in current and former smokers
- Sponsor: NCI; Dutch-Belgian consortium
- Enrolled: 53454
- Result: Lung cancer mortality reduced 20% (NLST) and 24% in men (NELSON).
- Outcomes: NLST: relative reduction in lung cancer mortality: Low-dose CT vs chest X-ray 20%; NELSON: relative reduction in lung cancer mortality at 10 years (men): Low-dose CT vs no screening 24%
- Replication: Two independent randomised trials on two continents agree; MILD and LUSI are consistent.

## Sources

- ClinicalTrials.gov NCT00047385: https://clinicaltrials.gov/study/NCT00047385
- NELSON, NEJM 2020: https://www.nejm.org/doi/full/10.1056/NEJMoa1911793

## Connected records

- cancers: [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [Resectable stage I to III non-small-cell lung cancer](https://onco.cc/cancers/resectable-nsclc/)
- technologies: [CT (computed tomography)](https://onco.cc/technologies/ct/), [Low-dose CT lung screening](https://onco.cc/technologies/low-dose-ct-screening/), [NHS Targeted Lung Health Check (lung cancer screening programme)](https://onco.cc/technologies/nhs-targeted-lung-health-check/), [Tumour volume doubling time](https://onco.cc/technologies/tumour-doubling-time/)
- people: [Denise R. Aberle](https://onco.cc/people/denise-aberle/), [Harry J. de Koning](https://onco.cc/people/harry-de-koning/)
- trials: [UKLS](https://onco.cc/trials/ukls/)
- institutions: [National Cancer Institute (NIH)](https://onco.cc/institutions/nci/)
- bottlenecks: [Overdiagnosis and false alarms](https://onco.cc/bottlenecks/b-overdiagnosis/), [The hardest cancers are found late](https://onco.cc/bottlenecks/b-early-detection/)
- key papers: [NELSON: volume-based CT screening reduces lung cancer deaths with fewer false alarms](https://onco.cc/key-papers/paper-nelson-nejm-2020/), [NLST: yearly low-dose CT scans cut lung cancer deaths in heavy smokers](https://onco.cc/key-papers/paper-nlst-nejm-2011/)
- roadmaps: [Cancer prevention roadmap: tobacco control and vaccines → biomarker-guided chemoprevention → interception in carriers](https://onco.cc/roadmaps/prevention-roadmap/)

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