Co-occurrence of bronchiectasis, airway wall thickening, and emphysema in Chinese low-dose CT screening

Objective: To assess the co-occurrence of incidental CT lung findings (emphysema, bronchiectasis, and airway wall thickening) as well as associated risk factors in low-dose CT (LDCT) lung cancer screening in a Chinese urban population.

Methods: Data from 978 participants aged 40-74 years from the Chinese NELCIN-B3 urban population study who underwent LDCT screening were selected. CT scans were reviewed for incidental lung findings: emphysema, bronchiectasis and airway wall thickness. Emphysema was defined in three ways (≥ trace, ≥ mild, or ≥ moderate) depending on severity. Participants were described and stratified by presence or absence of incidental lung findings. Logistic regression analyses were performed to examine the relationship between participant characteristics and CT findings.

Results: Mean age was 61.3 years ± 6.8 and 533 (54.6%) were female. 48% of participants had incidental lung findings: 19.9% had emphysema (≥ mild), 9.2% had bronchiectasis, and 35.7% had airway wall thickening. Among 978 participants, 2.1% showed all three findings. Multivariable analysis showed that higher age (OR: 1.06; 95% CI: 1.04-1.08; p < 0.001), male sex (OR: 1.68; 95% CI: 1.14-2.47; p = 0.008) smoking history (OR: 1.76; 95% CI: 1.02-3.03; p = 0.04 for former smokers; OR: 2.45; 95% CI: 1.59-3.78; p < 0.001 for current smokers), and the presence of respiratory symptoms (OR: 1.42; 95% CI: 1.01-2.00; p = 0.04) were associated with the risk of having at least one incidental lung findings. When different definitions of emphysema were used, the results remained consistent.

Conclusion: In a Chinese urban population undergoing LDCT lung cancer screening, 48% had at least one incidental CT lung finding, which was associated with higher age, male sex, questionnaire-based respiratory symptoms and smoking history.

Key points: Question Reporting of incidental lung findings that indicate lung disease risk lacks consensus in the cancer screening setting and needs evidence of co-occurrence in general populations. Findings Almost half of the 978 participants had at least one incidental lung CT finding; these were associated with older age, male sex, respiratory symptoms, and smoking history. Clinical relevance Incidental lung findings and related risk factors are often observed in low-dose CT lung cancer screening, and careful consideration of their relevance should be given to their inclusion in future screenings.