Lung Cancer Screening Guidelines

Eligibility Criteria

• The National Comprehensive Cancer Network (NCCN) defines two high-risk groups eligible for low-dose CT (LDCT) screening: individuals aged ≥50 years with ≥20 pack-year smoking history who currently smoke or quit within 15 years, and individuals aged ≥50 years with ≥20 pack-year smoking history plus one additional risk factor, which can include family history 1, 2, 3
• Having a first-degree relative with lung cancer increases risk by 1.8-fold (95% CI: 1.6-2.0), with greater risk associated with multiple affected family members or young age at diagnosis 4, 5

Primary Prevention

• The NCCN strongly counsels against ever starting smoking, as tobacco smoking accounts for approximately 85% of lung cancer deaths, with no risk-free level of tobacco exposure and a clear dose-response relationship 6

Risk Factor Documentation

• Documenting specific family history details, such as which relative(s), age at diagnosis, and smoking status, is important for assessing personal risk, with multiple affected family members or young age at diagnosis in relatives increasing personal risk 4, 5

Future Screening Eligibility

• If an individual remains a never-smoker, they will not meet screening criteria based on current guidelines, regardless of family history, but if they develop a smoking history, they would become eligible for screening at age 50 with ≥20 pack-years of smoking history, given their family history as an additional risk factor 1, 2, 3

Common Pitfalls to Avoid

• The NCCN recommends avoiding low-dose CT screening based on family history alone in young patients, as it exposes patients to unnecessary radiation without proven benefit, and instead focusing on primary prevention through tobacco avoidance 3, 4, 5, 6