# Low-dose CT lung screening

Source: https://onco.cc/technologies/low-dose-ct-screening/  
OnCo record `low-dose-ct-screening` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A yearly low-radiation CT scan for current and former heavy smokers that finds lung cancer early enough to cure it.

## Summary

Proven by NLST (20% mortality reduction) and NELSON (24% in men). US eligibility: age 50-80, ≥20 pack-years, quit <15 years. Uptake remains under 20% in the US and lower elsewhere; risk models (PLCOm2012), AI nodule scoring (Sybil, Optellum), and blood biomarkers aim to widen and sharpen eligibility. Lung-RADS standardises reporting; volumetric management (NELSON) reduces false positives.

## Fields

- Kind: Technology
- Status: standard-of-care
- Last checked: 2026-09-06
- Principle: Non-contrast helical CT at ~1-1.5 mSv; nodules classified by size, volume, growth, and morphology; AI assists detection and malignancy scoring.
- Since: 2011
- Strengths: Only proven mortality-reducing intervention for lung cancer detection; Also detects emphysema and coronary calcium
- Limitations: Low uptake; False positives and incidental findings; Misses never-smoker adenocarcinomas (rising in East Asia, where risk-based screening is debated)

## Notes

- The two randomised results screening rests on. The National Lung Screening Trial randomised 53,454 people aged 55 to 74 with 30 or more pack-years to three annual low-dose CT scans or chest radiographs and found 20.0 percent fewer lung cancer deaths (95 percent confidence interval 6.8 to 26.7) and 6.7 percent fewer deaths from any cause. NELSON randomised 13,195 men and 2,594 women aged 50 to 74 to volume CT at baseline and years 1, 3 and 5.5 or to no screening, and found a lung cancer death rate ratio of 0.76 (0.61 to 0.94) in men at ten years and 0.67 (0.38 to 1.14) in women. The number needed to screen to prevent one lung cancer death is 323 over 6.5 years and 130 over ten years respectively.
- The harms, measured. In the National Lung Screening Trial 24.2 percent of low-dose CT screens were positive and 96.4 percent of those positives were false; false positives led to 17 invasive procedures per 1,000 people screened (number needed to harm 59) and fewer than one major complication. Incidental findings were reported in 4.4 to 40.7 percent of people screened and overdiagnosis estimates ranged from 0 to 67 percent (US Preventive Services Task Force evidence report, JAMA 2021). NELSON's volume-based protocol referred only 2.1 percent of participants for a suspicious nodule, and 9.2 percent had one extra scan for an initially indeterminate result, which is why the harm figures differ by protocol as much as by population.
- Where the programmes start. The US Preventive Services Task Force recommends annual low-dose CT from 50 to 80 for people with a 20 pack-year history who smoke or quit within the past 15 years (grade B, 2021), replacing the 55 to 80 and 30 pack-year criteria of 2013. The UK National Screening Committee recommended targeted screening at 55 to 74 with integrated smoking cessation in June 2022, and England screens above a modelled risk threshold rather than a pack-year cut-off.
- Lung cancer in the UK: Roy Castle Lung Cancer Foundation runs information on lung health checks, the NHS targeted lung cancer screening programme, and supports the roll-out of screening and self-request chest X-ray services. For someone already diagnosed, the relevant part is family and friends: the NHS says to see a GP for a cough lasting longer than 3 weeks or any other symptom of lung cancer, and to ask for an urgent GP appointment or NHS 111 help after coughing up blood.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Lung_cancer_screening
- Wikipedia: https://en.wikipedia.org/wiki/Lung_cancer_screening
- National Lung Screening Trial Research Team, N Engl J Med 2011: reduced lung-cancer mortality with low-dose computed tomographic screening (53,454 people): https://doi.org/10.1056/nejmoa1102873
- de Koning, N Engl J Med 2020: NELSON, reduced lung-cancer mortality with volume CT screening in a randomised trial (13,195 men and 2,594 women): https://doi.org/10.1056/nejmoa1911793
- US Preventive Services Task Force, JAMA 2021: screening for lung cancer, recommendation statement (annual low-dose CT at 50 to 80 with 20 pack-years, grade B): https://doi.org/10.1001/jama.2021.1117
- Jonas, JAMA 2021: screening for lung cancer with low-dose computed tomography, updated evidence report for the US Preventive Services Task Force (223 publications, 7 randomised trials, 86,486 people): https://doi.org/10.1001/jama.2021.0377
- Roy Castle Lung Cancer Foundation: getting diagnosed: https://roycastle.org/learn-about-lung-cancer/getting-diagnosed/
- NHS: symptoms of lung cancer: https://www.nhs.uk/conditions/lung-cancer/symptoms/

## 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/), [Small-cell lung cancer](https://onco.cc/cancers/sclc/)
- fronts: [Early Detection & Screening](https://onco.cc/fronts/early-detection/), [Imaging](https://onco.cc/fronts/imaging/)
- technologies: [AI in radiology](https://onco.cc/technologies/radiology-ai-screening/), [CT (computed tomography)](https://onco.cc/technologies/ct/), [Endoscopic ultrasound and EBUS systems](https://onco.cc/technologies/endoscopic-ultrasound-systems/), [NHS Targeted Lung Health Check (lung cancer screening programme)](https://onco.cc/technologies/nhs-targeted-lung-health-check/), [Photon-counting CT](https://onco.cc/technologies/photon-counting-ct/), [Radiomics](https://onco.cc/technologies/radiomics/), [Smoking cessation in cancer patients](https://onco.cc/technologies/smoking-cessation-after-diagnosis/), [X-ray radiography and fluoroscopy](https://onco.cc/technologies/x-ray-radiography-fluoroscopy/)
- terms: [Family Smoking Prevention and Tobacco Control Act 2009](https://onco.cc/terms/tobacco-control-act/), [Lung cancer after chest radiotherapy and after alkylating chemotherapy](https://onco.cc/terms/second-primary-lung-after-chest-radiotherapy/), [Lung cancer in never-smokers](https://onco.cc/terms/never-smoker-lung-cancer/), [Lung-RADS and nodule reporting](https://onco.cc/terms/lung-rads/), [Pack-year](https://onco.cc/terms/pack-year/), [Pulmonary nodule](https://onco.cc/terms/pulmonary-nodule/), [Screening survivors: where the UK, American and European answers differ](https://onco.cc/terms/rejuv-second-screening-after-treatment-compared/), [Targeted lung health check](https://onco.cc/terms/targeted-lung-health-check/)
- trials: [CALGB 140503 (Alliance)](https://onco.cc/trials/calgb-140503/), [Lung-SEARCH](https://onco.cc/trials/lungsearch/), [NLST & NELSON (low-dose CT screening)](https://onco.cc/trials/nlst-nelson/), [SUMMIT (lung health check study)](https://onco.cc/trials/summit-lung/), [Tobacco Education and Lung Health Study (TEAL)](https://onco.cc/trials/nct06290869/), [UKLS](https://onco.cc/trials/ukls/), [YLST](https://onco.cc/trials/ylst/)
- key papers: [Evaluation of USPSTF Lung Cancer Screening Guidelines Among African American Adult Smokers](https://onco.cc/key-papers/paper-aldrich-uspstf-screening-african-american-smokers-jama-oncol-2019/), [Genomic and evolutionary classification of lung cancer in never smokers](https://onco.cc/key-papers/paper-zhang-lung-cancer-never-smokers-nat-genet-2021/), [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/), [Screening by chest radiograph and lung cancer mortality: the Prostate, Lung, Colorectal, and Ovarian (PLCO) randomized trial](https://onco.cc/key-papers/paper-plco-chest-radiograph-lung-cancer-mortality-jama-2011/), [Screening for Lung Cancer: US Preventive Services Task Force Recommendation Statement](https://onco.cc/key-papers/paper-uspstf-lung-cancer-screening-jama-2021/)
- ideas: [Decide who is screened for lung cancer by individual risk, not by pack-years](https://onco.cc/ideas/idea-lung-screening-eligibility-by-risk-not-pack-years/), [Require stage-shift or interval-cancer endpoints for AI in cancer screening](https://onco.cc/ideas/idea-data-ai-screening-endpoints/), [Treat lung cancer in never-smokers as its own disease, with its own detection programme](https://onco.cc/ideas/idea-lung-never-smoker-disease-its-own-programme/)
- institutions: [Cheshire and Merseyside Cancer Alliance](https://onco.cc/institutions/cheshire-merseyside-cancer-alliance/), [East Midlands Cancer Alliance](https://onco.cc/institutions/east-midlands-cancer-alliance/), [East of England Cancer Alliance](https://onco.cc/institutions/east-of-england-cancer-alliance/), [Greater Manchester Cancer Alliance](https://onco.cc/institutions/greater-manchester-cancer-alliance/), [Humber & North Yorkshire Cancer Alliance](https://onco.cc/institutions/humber-north-yorkshire-cancer-alliance/), [Kent and Medway Cancer Alliance](https://onco.cc/institutions/kent-medway-cancer-alliance/), [Lancashire and South Cumbria Cancer Alliance](https://onco.cc/institutions/lancashire-south-cumbria-cancer-alliance/), [Liverpool Heart and Chest Hospital NHS Foundation Trust](https://onco.cc/institutions/liverpool-heart-and-chest/), [Markey Cancer Center, University of Kentucky](https://onco.cc/institutions/kentucky-markey/), [MUSC Hollings Cancer Center](https://onco.cc/institutions/musc-hollings/), [North Central London Cancer Alliance](https://onco.cc/institutions/north-central-london-cancer-alliance/), [North East London Cancer Alliance](https://onco.cc/institutions/north-east-london-cancer-alliance/), [Northern Cancer Alliance](https://onco.cc/institutions/northern-cancer-alliance/), [Peninsula Cancer Alliance](https://onco.cc/institutions/peninsula-cancer-alliance/), [Roy Castle Lung Cancer Foundation](https://onco.cc/institutions/roy-castle-lung-cancer-foundation/), [Somerset, Wiltshire, Avon and Gloucestershire Cancer Alliance](https://onco.cc/institutions/swag-cancer-alliance/), [South East London Cancer Alliance](https://onco.cc/institutions/south-east-london-cancer-alliance/), [South Yorkshire and Bassetlaw Cancer Alliance](https://onco.cc/institutions/south-yorkshire-bassetlaw-cancer-alliance/), [Surrey and Sussex Cancer Alliance](https://onco.cc/institutions/surrey-sussex-cancer-alliance/), [Thames Valley Cancer Alliance](https://onco.cc/institutions/thames-valley-cancer-alliance/), [Wessex Cancer Alliance](https://onco.cc/institutions/wessex-cancer-alliance/), [West Midlands Cancer Alliance](https://onco.cc/institutions/west-midlands-cancer-alliance/), [West Yorkshire and Harrogate Cancer Alliance](https://onco.cc/institutions/west-yorkshire-harrogate-cancer-alliance/)
- people: [David Baldwin](https://onco.cc/people/david-baldwin/), [John Field](https://onco.cc/people/john-field/), [Lecia V. Sequist](https://onco.cc/people/lecia-sequist/), [Matthew Callister](https://onco.cc/people/matthew-callister/), [Philip Crosbie](https://onco.cc/people/philip-crosbie/), [Weimin Li](https://onco.cc/people/li-weimin/)
- bottlenecks: [Overdiagnosis and false alarms](https://onco.cc/bottlenecks/b-overdiagnosis/), [The hardest cancers are found late](https://onco.cc/bottlenecks/b-early-detection/)
- collections: [American Cancer Society (ACS)](https://onco.cc/collections/american-cancer-society/), [Australia's national cancer screening programs](https://onco.cc/collections/australia-cancer-screening-programs/), [LUNGevity Foundation (and GO2 for Lung Cancer)](https://onco.cc/collections/lungevity/), [NHS cancer screening programmes](https://onco.cc/collections/nhs-cancer-screening-programmes/)
- drugs: [Optellum Virtual Nodule Clinic](https://onco.cc/drugs/optellum-virtual-nodule-clinic/)
- companies: [Optellum](https://onco.cc/companies/optellum/)
- roadmaps: [Cancer prevention roadmap: tobacco control and vaccines → biomarker-guided chemoprevention → interception in carriers](https://onco.cc/roadmaps/prevention-roadmap/)

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