Medicine
Cost-effectiveness of Lung Cancer Screening with Low-Dose CT
Quick fact
Modeling studies have shown that screening long-term smokers with low-dose CT costs about $81,000 per quality-adjusted life year gained, which is right at the common US willingness-to-pay threshold of $100,000–$150,000, making it borderline cost-effective for high-risk groups.
Why this is interesting
Lung cancer is the leading cause of cancer death, but not every CT scan is worth the money. How do we decide whether screening is actually cost-effective?
Read the full explanation
Understanding Cost-effectiveness of Lung Cancer Screening with Low-Dose CT
Think of cost-effectiveness analysis like a budget-conscious car buyer: you want the most safety per dollar. For lung cancer screening, we compare the extra cost of low-dose CT (including follow-up tests and procedures) against the extra health benefit, measured in quality-adjusted life years (QALYs). A QALY combines quantity and quality of life—a year in perfect health is 1 QALY, and a year with reduced health is less. Screening a smoker aged 55–80 with a 30 pack-year history catches early-stage cancers, which are more treatable, adding healthy years. But it also leads to false alarms and invasive biopsies for benign nodules. The analysis adds up all these costs and outcomes, then calculates the incremental cost-effectiveness ratio (ICER)—the cost per additional QALY gained. If that ratio falls below a society's willingness-to-pay threshold (e.g., $100,000 per QALY in the US), the screening is considered cost-effective.
A deeper explanation
The mechanism of cost-effectiveness analysis (CEA) for lung cancer screening involves decision models, typically Markov or microsimulation, that simulate the natural history of lung cancer in a target population. These models incorporate probabilities of nodule detection, biopsy, surgery, and treatment outcomes, as well as the costs of CT scans, follow-up imaging, and procedures. They also include the long-term effects on survival and quality of life. The key output is the incremental cost-effectiveness ratio (ICER), calculated as (Costscreening – Costnoscreening) / (QALYsscreening – QALYsnoscreening). Screening is deemed cost-effective if the ICER is below a society's willingness-to-pay threshold. For low-dose CT, the US Preventive Services Task Force and other bodies found that screening high-risk groups (older, heavy smokers) yields an ICER within acceptable ranges, especially when risk-stratified. However, the benefit shrinks and costs rise when applied to lower-risk groups, and harms like overdiagnosis (detecting cancers that wouldn't cause symptoms) and false positives can significantly increase downstream costs and reduce QALYs. This is why cost-effectiveness analyses are crucial for setting screening policies—they balance patient benefit against financial and psychological harms.