What are the guidelines for low-dose computed tomography (low-dose CT) chest screening for lung cancer?

Low-Dose CT Chest Screening Guidelines for Lung Cancer

Annual low-dose CT screening should be offered to asymptomatic individuals aged 55-77 who have smoked 30+ pack-years and either continue to smoke or have quit within the past 15 years. 1

Primary Eligibility Criteria

Strong Evidence-Based Recommendations:

• Primary eligibility group (Strong recommendation, moderate-quality evidence):
  • Age: 55-77 years
  • Smoking history: ≥30 pack-years
  • Current smokers OR former smokers who quit within past 15 years
  • Asymptomatic (no symptoms suggesting lung cancer)
  • Healthy enough to undergo treatment if cancer is detected 1

Extended Eligibility Groups:

• Secondary eligibility group (Weak recommendation, moderate-quality evidence):

  • Age: 50-80 years
  • Smoking history: ≥20 pack-years
  • Current smokers OR former smokers who quit within past 15 years 1

• Risk calculator-based eligibility (Weak recommendation, moderate-quality evidence):

  • Individuals who don't meet above criteria but have high predicted benefit based on validated risk calculators
  • Examples include LYFS-CT, LCDRAT, LCRAT, PLCOm2012, or Bach calculators 1

Who Should NOT Be Screened

• Individuals with comorbidities that substantially limit life expectancy or ability to tolerate evaluation/treatment (Strong recommendation) 1
• Individuals younger than 50 or older than 80 years 1
• Those who quit smoking >15 years ago (without high risk on calculators) 1
• Symptomatic individuals (should receive diagnostic testing instead) 1

Screening Implementation

Pre-Screening Requirements:

• Effective counseling and shared decision-making visit prior to LDCT 1
• Assessment for symptoms suggesting lung cancer 1
• Discussion of benefits, harms, and follow-up testing requirements 1
• Confirmation of willingness to accept treatment if cancer is detected 1

Technical Parameters:

• Programs should define a positive test based on nodule size threshold:
  • 4mm, 5mm, or 6mm in diameter is acceptable 1
  • For part-solid nodules, size based on solid component 1
  • LungRADS reporting system commonly uses 6mm at baseline and 4mm for new nodules on annual scans 1

Follow-Up Management:

• Comprehensive approach to nodule management with multi-disciplinary expertise 1
• Strategies to maximize compliance with annual screening 1
• Strategies to minimize overtreatment of potentially indolent cancers 1

Evolution of Guidelines

The 2021 CHEST guidelines 1 updated the 2018 recommendations 1 with expanded eligibility criteria. The US Preventive Services Task Force similarly expanded their recommendations in 2021 to include individuals aged 50-80 with ≥20 pack-year history 2.

Important Considerations and Pitfalls

• False positives: Small pulmonary nodules are common and most are not malignant 3
• Screening is for asymptomatic individuals only: Symptomatic patients should receive diagnostic testing instead 1
• Adherence challenges: Programs should develop strategies to maximize compliance with annual screening 1
• Implementation barriers: Provider awareness and insurance issues can limit screening uptake 4
• Multidisciplinary approach: Comprehensive nodule management requires expertise from pulmonology, radiology, thoracic surgery, and oncology 1

The evidence suggests that low-dose CT screening for lung cancer results in a favorable but tenuous balance of benefit and harms. Selection of appropriate candidates, quality imaging, proper interpretation, and effective management of findings are critical to maintain this balance 1.