Quantitative severity of pulmonary emphysema as a prognostic factor for recurrence in patients with surgically resected non-small cell lung cancer

Abstract

Background Pulmonary emphysema is a major component of chronic obstructive pulmonary disease and lung cancer. However the prognostic significance of quantitative emphysema severity in patients with lung cancer is unclear. We analyzed whether numerical emphysema value is a prognostic factor for recurrence in patients with surgically resected non-small cell lung cancer. Methods We quantified emphysema severity of the whole lung and regional lobes in 45 patients (mean age 68.0 years) using an automated chest computed tomography-based program. Predictive factors for recurrence were investigated using a Cox proportional hazards model. Recurrence-free and overall survival was compared after dichotomization of patients according to whole lung emphysema severity. Results The mean percentage emphysema ratio of the whole lung was 1.21 +/- 2.04. Regional lobar emphysema severity was highest in the right middle lobe (1.93 +/- 0.36), followed by right upper (1.35 +/- 2.50), left upper (1.34 +/- 2.12), left lower (1.05 +/- 2.52), and right lower (0.78 +/- 2.28) lobes. The low severity group showed significantly longer overall survival compared to the high severity group (log-rank test, P = 0.018). Quantitative emphysema severity of the whole lung (hazard ratio 1.36; 95% confidence interval 1.0-1.73) and stage III (hazard ratio 6.17; 95% confidence interval 1.52-25.0) were independent predictors of recurrence after adjusting for age, gender, smoking status, and forced expiratory volume in one second. Conclusion The severity of whole lung emphysema was independently associated with recurrence. Patients with non-small cell lung cancer and marginal pulmonary emphysema at lower severity survive longer after curative-intent surgery.