Low‑Dose CT for Lung Cancer Screening in a High‑Risk Population
Lung cancer remains the leading cause of cancer‑related death worldwide. Early detection is the most effective way to improve survival, and low‑dose computed tomography (LDCT) has emerged as the preferred screening tool for individuals at elevated risk. This article reviews the evidence, implementation strategies, and international perspectives on LDCT screening for high‑risk groups.
Who Is Considered High Risk?
Guidelines from the United States Preventive Services Task Force (USPSTF) and the European Society of Radiology define high risk primarily by age and smoking history:
- Age: 55–80 years (some programs extend to 50 years).
- Smoking exposure: ≥30 pack‑years, current smokers, or those who quit within the past 15 years.
- Additional risk factors: occupational exposure (asbestos, radon), family history of lung cancer, or chronic obstructive pulmonary disease (COPD).
Risk‑prediction models, such as the PLCOm2012, can further refine eligibility by incorporating comorbidities and demographic variables.
Evidence Supporting LDCT Screening
Key Clinical Trials
Two large randomized trials have established the mortality benefit of LDCT:
- National Lung Screening Trial (NLST): Conducted in the United States, the NLST enrolled 53,454 participants and demonstrated a 20% reduction in lung‑cancer mortality with annual LDCT compared with chest X‑ray.
- NELSON trial: Conducted in the Netherlands and Belgium, NELSON confirmed a 26% reduction in mortality for men and a 61% reduction for women after three LDCT screens over a 10‑year follow‑up.
