Serum Tumor Markers Are Not Recommended for Lung Cancer Screening
Serum tumor markers should not be ordered for lung cancer screening in adults with risk factors who are concerned about the disease. The appropriate screening test is low-dose computed tomography (LDCT), not blood tests. 1, 2
Why Tumor Markers Are Not Used for Lung Cancer Screening
No Validated Serum Markers for Screening
Current guidelines from NCCN, USPSTF, and the American Cancer Society do not recommend any serum tumor markers for lung cancer screening or early detection. 1
Unlike some other cancers (e.g., PSA for prostate cancer), there are no blood-based biomarkers with sufficient sensitivity and specificity to detect early-stage lung cancer. 3
Tumor markers may be used in the management of diagnosed lung cancer (for monitoring treatment response or recurrence), but they have no role in screening asymptomatic individuals. 3
The Only Recommended Screening Modality
Annual low-dose CT (LDCT) is the only validated screening test for lung cancer that has demonstrated mortality reduction in randomized controlled trials. 1, 2, 4
The National Lung Screening Trial (NLST) demonstrated a 20% reduction in lung cancer mortality with LDCT screening compared to chest radiography. 1, 4
Chest radiography is explicitly not recommended for lung cancer screening, as it does not reduce lung cancer mortality. 1, 2
Who Should Be Screened with LDCT
Current USPSTF Criteria (2021)
Age 50-80 years with ≥20 pack-year smoking history who currently smoke or quit within the past 15 years. 1, 2, 4
Screening should be discontinued once a person has not smoked for 15 years or develops health problems that substantially limit life expectancy or ability to undergo curative lung surgery. 2, 4
NCCN High-Risk Groups
Group 1 (Category 1):
- Age 55-74 years with ≥30 pack-year smoking history who currently smoke or quit within 15 years. 1
Group 2 (Category 2A):
Age ≥50 years with ≥20 pack-year smoking history PLUS one additional risk factor such as: 1, 2, 5
- Personal history of cancer
- Chronic lung disease (COPD, pulmonary fibrosis)
- First-degree relative with lung cancer
- Occupational carcinogen exposure (asbestos, arsenic, chromium, nickel, silica)
- Radon exposure
The NCCN panel removed the upper age cutoff in 2021, stating that screening should continue as long as the individual remains a candidate for curative-intent treatment, rather than using an arbitrary chronological age. 1
Important Exclusions
Individuals younger than 50 years should not be screened, regardless of smoking history or family history. 2, 6, 5
Secondhand smoke exposure alone is not considered an independent risk factor sufficient to warrant screening. 2
Patients with health problems that preclude curative treatment or require home oxygen should not be screened. 2
Essential Implementation Requirements
Screening Must Occur in High-Quality Centers
- LDCT screening should only be performed at high-volume, high-quality centers with: 1, 2
- Multidisciplinary teams (chest radiology, pulmonary medicine, thoracic surgery)
- Expertise in LDCT interpretation and lung nodule management
- Access to comprehensive diagnostic and treatment services
Mandatory Shared Decision-Making
- Clinicians must engage in shared decision-making discussions that include: 1, 2
- Benefits of screening (20% reduction in lung cancer mortality)
- Harms of screening (false positives, overdiagnosis in 10-12% of cases, radiation exposure, anxiety)
- The critical importance of smoking cessation
Smoking Cessation Is the Priority
Vigorous smoking cessation counseling is the single most effective intervention to reduce lung cancer risk, more effective than screening itself. 2, 6
Combined behavioral counseling and pharmacotherapy (nicotine replacement, bupropion, or varenicline) yields higher quit rates than either component alone. 2, 6
Current smokers must be referred to cessation programs, and screening is not a substitute for quitting. 1, 2
Common Pitfalls to Avoid
Do Not Order These Tests
Serum tumor markers have no role in lung cancer screening. 3
Chest X-ray does not reduce lung cancer mortality and should not be used for screening. 1, 2
Sputum cytology lacks adequate sensitivity and specificity for screening. 2, 3
Standard-dose chest CT delivers excessive radiation compared to low-dose protocols and is not appropriate for screening. 2
Screening Frequency Matters
Annual LDCT is required; one-time screening does not confer the demonstrated mortality benefit. 2, 4
The NLST protocol used annual screening, and this is the only interval with proven efficacy. 1, 4
Do Not Screen Ineligible Patients
Screening individuals who do not meet eligibility criteria exposes them to radiation, false positives requiring invasive follow-up, and overdiagnosis without proven benefit. 2, 6
Using only the narrow NLST criteria (age 55-74, ≥30 pack-years) would identify only 27% of patients currently being diagnosed with lung cancer, which is why NCCN expanded criteria to include additional risk factors. 1, 2
The Bottom Line
For an adult concerned about lung cancer, assess their eligibility for LDCT screening based on age, smoking history, and additional risk factors. If they meet criteria, refer them to a high-quality screening center after shared decision-making. If they do not meet criteria, focus on smoking cessation counseling and avoid ordering serum tumor markers, which have no validated role in lung cancer screening. 1, 2, 4