What are the guidelines for lung cancer screening in high-risk individuals, particularly those with a significant smoking history?

Lung Cancer Screening Guidelines for High-Risk Individuals

Annual low-dose computed tomography (LDCT) screening is recommended for individuals aged 50-80 years with a ≥20 pack-year smoking history who currently smoke or have quit within the past 15 years. 1

Eligibility Criteria for Lung Cancer Screening

Primary High-Risk Population

• Adults aged 50-80 years with a ≥20 pack-year smoking history who currently smoke or have quit within the past 15 years 1
• This represents the most recent USPSTF recommendation (2021), which expanded eligibility from the previous 2013 criteria (ages 55-80 years with ≥30 pack-year history) 1
• The expanded criteria are estimated to increase screening eligibility and result in more lung cancer deaths averted and life-years gained 2

Additional High-Risk Populations to Consider

• Individuals aged ≥50 years with ≥20 pack-year smoking history and additional risk factors (such as family history of lung cancer, occupational exposures, radon exposure, history of lung disease) 3, 4
• Long-term cancer survivors aged 55-79 years 3
• Individuals with a smoking history of <30 pack-years may also benefit from screening, though evidence is less robust 3

Screening Protocol

Screening Modality and Technique

• Screening should be performed using LDCT with the following parameters 3:
  • 120-140 kVp, 20-60 mAs
  • Average effective dose of 1.5 mSv or less
  • Collimation of 2.5 mm or less

Frequency and Duration

• Annual screening is recommended 3
• Screening should be discontinued when 1:
  • The individual has not smoked for 15 years
  • The individual develops a health problem that substantially limits life expectancy
  • The individual is no longer a candidate for curative lung surgery

Management of Positive Findings

• A nodule size of 5 mm or more indicates a positive result requiring 3-month follow-up CT 3
• Nodules of 15 mm or more should undergo immediate further diagnostic procedures 3
• Follow-up CT should be performed as a limited LDCT scan covering only the area of the nodule 3

Implementation Considerations

Screening Setting Requirements

• Screening should be performed in organized screening programs with expertise in LDCT screening 3
• Programs should have access to a multidisciplinary team with expertise in evaluation, diagnosis, and treatment of abnormal lung findings 3
• Teams should include board-certified thoracic surgeons, thoracic radiologists, pulmonologists, and oncologists 3

Patient Education and Shared Decision-Making

• Individuals should be counseled about potential benefits and harms of screening 3
• Benefits include reduced lung cancer mortality (20-25% reduction compared to no screening) 1, 5
• Harms include false-positive results (27.3% in initial screening round), unnecessary invasive procedures, radiation exposure, and potential overdiagnosis 5, 6

Quality Assurance

• Individuals who are screened should be enrolled in a registry to capture data on follow-up testing, radiation exposure, patient experience, and smoking behavior 3
• Quality metrics should be developed to enhance benefits and minimize harms 3

Common Pitfalls and Caveats

• False-positive results are common (27.3% in initial screening) and can lead to unnecessary anxiety and procedures 5, 6
• For every 1000 persons screened, false-positive results may lead to approximately 17 invasive procedures 5
• Overdiagnosis (detection of cancers that would not have caused symptoms or death) estimates vary widely from 0% to 67% 5
• Incidental findings are common (4.4%-40.7% of persons screened) and require appropriate management 5
• Risk-based approaches using prediction models may improve screening efficiency compared to using age and smoking history alone 7