Relationship Between Emphysema and Lung Cancer Risk: Preliminary Results

Purpose of the Study: To determine the relationship between lung cancer and emphysema by using high-precision 3D image analysis tools on volumetric thin-section CT data. Methods: Low-dose thin-section CT emphysema features of subjects with either symptomatic or screening-trial detected lung cancer (n=40) were compared with those of 992 controls recruited by the same lung cancer screening trial. All CT scans were obtained according to the same protocol and analyzed with a prototypical emphysema detection software (MeVis research), which provides a region-based assessment of the following parameters: lung volumes, mean lung density, emphysema index and four classes of emphysema clusters with different volumes. Multiple regression models were used to assess emphysema features as potential risk factor for lung cancer, after allowance for gender, age, body mass index (BMI), smoking history, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio. Results: We found no compelling evidence to suggest that any emphysema feature was associated with lung cancer. However, the likelihood of lung cancer was significantly higher amongst those with an FEV1/FVC ratio 8804; 92% predicted [odd ratio= 5.33, 95% confidence interval (CI) 1.79-15.86]. Conclusions: These results suggest an increased risk of lung cancer associated with airway obstruction. However, emphysema phenotypes as determined by thin-section CT were not associated with an increased risk of lung cancer.