Differences of Low-Dose Computed Tomography Findings Between Smokers and Nonsmokers Based on Smoking Cessation Program

Abstract

Background: There are many more trials for low-dose chest computed tomography (LDCT) screening than for chest radiography, as a recent study shows that low-dose chest CT screening for smokers may reduce lung cancer mortality. Objectives: To assess the differences of low-dose CT imaging features between smokers and non-smokers. Patients and Methods: A retrospective review of all current smokers who visited our hospital between August 2015 and May 2016 to quit smoking and who had received chest LDCT was conducted. The patients had received an LDCT screening during the same period; non-smokers were considered as the control group. The retrospective interpretation for the nodule numbers and size, lymphadenopathy, emphysema, bronchiectasis, as well as coronary artery calcifications was performed at univariate and multivariate analyses. Results: Among 304 patients (130 in the non-smoker group and 174 in the smoker group), the number and diameter of nodules, pleural lesions, lymphadenopathy, and bronchiectasis were not significantly different between the smoker and non-smoker groups. Emphysema was detected in 11 (8.5%) patients in the non- smoker group and 75 (43.1%) in the smoker group. Coronary artery calcifications developed in 22 patients (16.9%) in the non-smoker group and 60 patients (34.5%) in the smoker group. Respiratory bronchiolitis developed in two patients (1.5%) in the non-smoker group and 13 patients (7.5%) in the smoker group. With an increase in the smoking period, emphysema and coronary artery calcifications significantly increased (P = 0.002 and P = 0.007, respectively). Conclusion: In the LDCT findings, emphysema, coronary artery calcifications, and respiratory bronchiolitis were significantly different between smokers and non-smokers. In multivariate analysis, emphysema was only significantly different between smokers and non-smokers. With an increase in the smoking period, the occurrence of emphysema and coronary artery calcifications increased as well at univariate and multivariate analysis.