New research presented this week at the European Congress of Radiology 2026 (ECR 2026) suggests that a person’s body composition, as measured by CT scans, could play a significant role in predicting lung cancer risk. The findings, focused on men undergoing lung cancer screening, highlight how factors like muscle mass and fat distribution vary with age and smoking history, potentially offering a more nuanced approach to risk assessment. This development in lung cancer screening could lead to more personalized preventative care.
Researchers analyzed low-dose chest CT scans from 4,435 male participants in the NELSON lung cancer screening trial, utilizing an artificial intelligence-based system to assess body composition. The participants had an average age of 59.4 years and a mean smoking history of 42.2 pack-years. The analysis focused on quantifying skeletal muscle area (SMA) and subcutaneous adipose tissue area (SAT) at specific vertebral levels – T5, T8 and T10 – to calculate a fat-to-muscle ratio (FMR). This detailed assessment provides a more comprehensive picture of thoracic body composition than traditional screening methods.
The study revealed striking differences in body composition between current and former smokers. Current smokers, comprising 55% of the study group, exhibited significantly lower levels of both SAT and SMA compared to former smokers (45%). Specifically, current smokers had an average SAT of 372 cm² versus 441 cm² in former smokers (p<0.001), and SMA measured 501 cm² compared to 507 cm² (p<0.001). The fat-to-muscle ratio was also notably lower among current smokers, at 0.74 compared to 0.87 in former smokers (p<0.001). These findings underscore the impact of smoking on body composition and its potential link to lung cancer risk.
Age-Related Shifts in Body Composition
Beyond smoking status, the research also identified clear age-related changes in body composition. As participants aged, skeletal muscle area steadily declined, dropping from an average of 515 cm² in those aged 50–54 years to 472 cm² in individuals 70 years and older (p<0.001). Conversely, subcutaneous adipose tissue increased with age, rising from 376 cm² to 443 cm² over the same period (p<0.001). The fat-to-muscle ratio also increased, moving from 0.70 to 0.90 (p<0.001). Importantly, these associations remained significant even after accounting for smoking status and cumulative smoking exposure, suggesting an independent effect of age on body composition.
These changes in body composition are not merely observational; they have potential implications for lung cancer risk. Muscle loss, known as sarcopenia, is increasingly recognized as a factor associated with poorer health outcomes, including increased susceptibility to chronic diseases. Similarly, changes in fat distribution can influence inflammation and metabolic function, potentially contributing to cancer development. Understanding these relationships is crucial for refining lung cancer screening strategies.
Improving Risk Stratification with CT Metrics
The researchers suggest that establishing reference values for CT-based body composition measures could significantly improve risk stratification within lung cancer screening populations. By incorporating these metrics into existing screening protocols, clinicians may be able to identify individuals at higher risk who could benefit from more intensive monitoring or preventative interventions. This personalized approach could lead to earlier detection and improved outcomes for those most vulnerable to lung cancer.
However, the study authors emphasize that further research is needed to determine how these body composition markers correlate with actual clinical outcomes in lung cancer screening settings. Although the findings provide a strong foundation for future investigations, more data is required to validate the predictive power of these CT-based measures. The NELSON trial, a large-scale study evaluating lung cancer screening with volume CT, provides a valuable dataset for this ongoing research. According to the NELSON trial, volume CT lung-cancer screening of high-risk individuals can reduce mortality.
The study, presented at ECR 2026, builds on growing evidence that body composition is a critical factor in overall health and disease risk. While the initial findings focus on men, researchers plan to investigate these relationships in women as well. The ultimate goal is to develop a more comprehensive and individualized approach to lung cancer screening, maximizing the benefits of early detection while minimizing unnecessary interventions.
The next step in this research involves analyzing the relationship between these body composition markers and the incidence of lung cancer within the NELSON study cohort, as detailed in the research presented by Xin Y et al. At the ECR Congress on March 4-8, 2026. This analysis will provide crucial insights into the predictive value of CT-based body composition measures and their potential to improve lung cancer screening strategies.
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