The association between emphysema detected on computed tomography and increased risk of lung cancer: a systematic review and meta-analysis

Background: Lung cancer, chronic obstructive pulmonary disease (COPD), and emphysema share common pathophysiological mechanisms, including diffuse chronic inflammation within lung tissue, oxidative stress, and lung destruction. This study aimed to evaluate the effectiveness of computed tomography (CT) imaging in predicting the risk of lung cancer development in patients with emphysema and COPD. Methods: The databases of PubMed, Embase, Web of Science, and Cochrane Library were searched to identify studies examining the relationship between CT-detected emphysema, COPD, and the risk of developing lung malignancy. The severity of emphysema (from trace to severe) was assessed visually and quantitatively on CT. COPD severity was classified from Global Initiative for Chronic Obstructive Lung Disease (GOLD) I to GOLD IV. Quality Assessment of Diagnostic Accuracy Studies, version 2 (QUADAS-2) was used to assess risk of bias in the included studies. Pooled odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were calculated for overall and stratified analyses. Results: Of the 6,114 studies screened, 12 (22,190 patients) were included. The overall pooled OR for lung cancer associated with CT-defined emphysema was 2.45 (95% CI: 2.01-2.99). In studies employing CT-based evaluation methods, the pooled OR for lung cancer was comparable between visual assessment (2.37; 95% CI: 1.93-2.80) and quantitative assessment (2.38; 95% CI: 1.85-3.05). The risk of lung cancer demonstrated a positive correlation with disease severity in both emphysema and COPD cases. Conclusions: CT-defined emphysema was linked to an elevated risk of lung cancer, which was observed across various assessments. Moreover, the severity of COPD was found also to be a risk factor for the development of lung cancer.