How often should smokers get low-dose computed tomography (low-dose CT) lung scans?

Low-Dose CT Lung Cancer Screening Frequency for Smokers

Annual low-dose CT screening is recommended for high-risk smokers aged 55-77 who have a smoking history of 30+ pack-years and are current smokers or have quit within the past 15 years. 1, 2

Primary Eligibility Criteria

• Strong recommendation (highest level of evidence):
  • Ages 55-77 years
  • ≥30 pack-year smoking history
  • Current smoker OR former smoker who quit within past 15 years
  • Asymptomatic individuals only 1, 2

Secondary Eligibility Criteria

• Moderate recommendation (moderate evidence):
  • Ages 50-80 years
  • ≥20 pack-year smoking history
  • Current smoker OR former smoker who quit within past 15 years 1, 3, 4

Risk Calculator-Based Eligibility

For individuals who don't meet the above criteria but may still benefit from screening based on validated risk calculators:

• Life-years gained: ≥16.2 days on LYFS-CT calculator
• Lung cancer death risk: ≥1.33% 5-year risk on LCDRAT with ≥10 years life expectancy
• Lung cancer incidence risk: ≥2.0% 5-year risk on LCRAT with ≥10 years life expectancy 1, 2

Screening Duration and Frequency

• Screening frequency: Annual (once per year) 1, 2
• When to discontinue screening:
  • After 15 years of smoking cessation
  • Development of health problems that substantially limit life expectancy
  • Development of health problems that limit ability/willingness to undergo curative lung surgery 1, 2, 3

Implementation Considerations

• Screening should be conducted in centers with multidisciplinary expertise (pulmonology, radiology, thoracic surgery, oncology) 1, 2
• Comprehensive nodule management protocols should be in place 2
• Shared decision-making discussion required before initiating screening 2
• Smoking cessation counseling should be provided to current smokers 2, 4

Important Caveats

• Screening is not a substitute for smoking cessation 1
• Symptomatic individuals should receive diagnostic testing, not screening 2
• Screening carries risks including false positives (leading to unnecessary procedures), radiation exposure, and potential overdiagnosis 5
• The optimal duration of screening beyond annual intervals is not definitively established 1

The most recent and highest quality evidence strongly supports annual screening for eligible high-risk individuals, with clear criteria for both starting and stopping the screening program.