Emphysema and lung cancer in population-based CT screening

Population screening for emphysema and lung cancer using CTScreening for lung cancer using CT is an effective strategy to reduce lung cancer mortality, but also leads to suboptimal referrals in retrospect. It is important to arrive at an optimal definition of a group of people who may be eligible for this screening. This thesis looked at the role of emphysema in identifying this group, both in the general Chinese and Dutch populations. First, we looked at the prevalence of emphysema and the epidemiological and radiological characteristics of emphysema based on CT. Then, the association of emphysema with lung cancer and lung nodules was examined. The main findings of this thesis show that Chinese never-smokers have a higher prevalence of CT-detected emphysema than the Dutch general population. Based on analysis of studies with a total of more than 107,000 participants, it appears that individuals with emphysema detected on CT have an increased risk of lung nodules and lung cancer. This risk increases with the severity of the emphysema. This applies to both emphysema diagnosed by visual and quantitative assessment on CT. In population screening with CT, the emphysema determination can be considered a predictor for lung cancer. This knowledge can be used to improve inclusion criteria and optimal frequency for lung cancer screening. In addition, uniform approaches for CT-based emphysema determination should be adopted to reliably determine the true burden of emphysema in different population groups and based on different CT systems