In this thesis of Jiali Cai, the prevalence, characteristics, and assessment of lung nodules in a Western general population is investigated. Lung nodules, including clinically relevant and actionable nodules, are not uncommon in a general Western population. Risk factors, including male sex, older age, low educational level, smoking, asbestos exposure, and COPD, all contribute to increased odds for an individual of having lung nodules, with similar associations observed for clinically relevant nodules. A family history of lung cancer contributes to the presence of lung nodules in never-smokers. When examining the CT characteristics of lung nodules, minor differences were identified between smokers and never-smokers. Approximately one-sixth of intermediate-sized solid nodules resolve during short-term follow-up, with younger age and irregular nodule edges being associated with resolving.
To assess the impact of different scan and evaluation protocols, this thesis reports the comparable performance of ultralow-dose CT and regular-dose CT in detecting and measuring nodules, demonstrating the feasibility of dose reduction in screening protocols. However, considerable variability in Lung-RADS performance across different populations was highlighted. Future research should focus on validate and explore (new) factors associated with nodule presence or resolving in diverse setting, refine evaluation protocols, and better correlate CT nodule findings with lung cancer diagnosis. These advancements will enhance lung nodule management in Western general population, particularly for non-smokers, and support the development of cost-effective lung cancer screening programs.
