Lung CT screening trial (NLST)

Overview

National Lung Screening Trial Research Team; Aberle DR et al.. N Engl J Med 2011 · PMID 21714641 · DOI 10.1056/NEJMoa1102873

Screening heavy smokers with low-dose CT cut lung-cancer deaths by 20% and deaths from any cause by 6.7%.

Does the study support the specific claim? No · Methodological quality: high

Original publication

Plain-language summary

Scientific in-depth review

1. Full reference

Authors

National Lung Screening Trial Research Team; Aberle DR et al.

Journal

N Engl J Med

Year

2011

Identifier

PMID 21714641 DOI 10.1056/NEJMoa1102873

Verification

verified – PubMed efetch 2026-10-26 (PublicationType and CommentsCorrections checked); Crossref 2026-10-26

Retracted

no

Corrections

none

Extent checked

abstract only

Conflicts of interest and funding

National Cancer Institute.

2. Research question

Does low-dose CT screening reduce lung-cancer mortality in high-risk persons?

3. Study design and population

Study design

Randomised controlled trial – Randomised controlled trial (33 US centres)

Population

53,454 persons at high risk for lung cancer (heavy smokers)

Country

USA

Period

Enrolment 2002-2004; follow-up to 31 Dec 2009

Sample size

53,454 (26,722 CT; 26,732 radiography)

Inclusion and exclusion criteria

High-risk current/former smokers

4. Methods and endpoints

Exposure / intervention

Three annual low-dose CT screens

Comparator

Three annual chest radiographs

Endpoints

Lung-cancer mortality, all-cause mortality, incidence, false positives

Statistical methods

Rate ratios; relative reduction with CI

5. Actual results

Results

Lung-cancer deaths 247 vs 309 per 100,000 person-years: relative reduction 20.0% (95% CI 6.8-26.7; P=0.004); all-cause mortality reduced 6.7% (1.2-13.6; P=0.02). Incidence 645 vs 572 per 100,000 person-years (RR 1.13, 1.03-1.23). Positive screens 24.2% vs 6.9%; 96.4% and 94.5% false positive.

Absolute risks

62 fewer lung-cancer deaths per 100,000 person-years

Authors' conclusion

Screening with low-dose CT reduces mortality from lung cancer.

6. Strengths

• Large RCT
• Mortality endpoint avoids lead-time bias
• High adherence

7. Weaknesses

• High false-positive rate
• Some overdiagnosis (higher incidence)
• Comparator was radiography, not no screening

8. Risk of bias

Orienting tool

RoB 2

Type of assessment

simplified assessment (abstract only)

Full formal assessment

no

Overall risk of bias

low

Rationale

Randomised, mortality endpoint, registry-confirmed deaths.

9. Assessment of the statistical interpretation

Recomputed rate ratio 0.799 (stats/C-CHM-13.py). Reported CI is asymmetric on the log scale, consistent with interim-monitoring adjustment; not an error.

10. Relevance to the specific claim

Directly refutes 'early diagnosis only makes you die early': earlier detection plus treatment reduced deaths, measured with a mortality endpoint that is immune to lead-time bias. It also documents overdiagnosis and false positives, which are real costs of screening.

11. Independent contrary findings

Welch 2000 (I-CHM-106) on misleading survival statistics.

12. Transferability to Germany and Europe

Replicated in Europe: NELSON trial (PMID 31995683, abstract read, not added) found a 10-year lung-cancer mortality rate ratio of 0.76 (0.61-0.94) in men.

13. Overall methodological judgement

High-quality evidence that early detection with treatment saves lives in high-risk groups.

14. Open questions

Balance of benefit and overdiagnosis outside high-risk groups.

15. Linked fact checks

• Oncology only buys time: 'survival rates' are meaningless, patients die during treatment, and early diagnosis only makes you 'die early'. – Studies contradicting or limiting the claim