title: Impact of COPD and emphysema on survival of patients with lung cancer: A meta-analysis of observational studies.
abstract: Both COPD and emphysema are associated with an increased incidence of lung cancer, but the impacts of these comorbidities on lung cancer prognosis are still unclear. Herein, we conducted a meta-analysis to clarify whether the presence of these comorbidities indicates poor survival in patients with lung cancer. A comprehensive search was conducted using PubMed, Embase, Web of Science, ASCO Abstracts and Cochrane library for articles published before 1 June 2015. Papers referenced by the obtained articles were also reviewed. Main outcomes were overall survival (OS) and disease-free survival (DFS) in patients with lung cancer. Pooled hazard ratio (HR) and 95% confidence intervals (CIs) were calculated using random-effects models. Subgroup and sensitivity analyses were also conducted. Of 58 full texts reviewed, 26 met our inclusion criteria that were derived from 21 and seven studies examining the impacts of COPD and emphysema on survival of lung cancer, respectively. Meta-analyses revealed that concomitant COPD was associated with poorer OS (HR, 1.17; 95% CI: 1.10-1.25, n = 20), which was independent of tumour staging, diagnostic criteria of COPD or location, and DFS (HR, 1.52; 95% CI: 1.04-2.23, n = 6) with high heterogeneity (I(2) = 78%). The presence of emphysema in patients with lung cancer predicted worse OS (HR, 1.66; 95% CI: 1.25-2.22, n = 7), but not poorer DFS. The presence of COPD and emphysema are robust predictors of poor survival in patients with lung cancer. Early detection of these diseases should be taken into account for lung cancer surveillance and management.
authors.affiliation: Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Yong-Hua
authors.initials: YH
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Wei-Jie
authors.initials: WJ
authors.lastname: Guan
authors.affiliation: Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Hua-Qi
authors.initials: HQ
authors.lastname: Wang
authors.affiliation: Department of Emergency Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.
authors.forename: Rong-Chang
authors.initials: RC
authors.lastname: Chen
authors.affiliation: Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Zhang
mesh_terms: D015897:Comorbidity; D019468:Disease Management; D018572:Disease-Free Survival; D042241:Early Diagnosis; D006801:Humans; D008168:Lung / Q000473:pathology*; D008175:Lung Neoplasms / Q000453:epidemiology / Q000473:pathology; D009367:Neoplasm Staging; D064887:Observational Studies as Topic; D011379:Prognosis; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology; D011656:Pulmonary Emphysema / Q000175:diagnosis / Q000453:epidemiology
keywords: chronic obstructive pulmonary disease; lung cancer; meta-analysis; prognosis