Jie Dai, Ming Liu, Gening Jiang and Ping Yang
Background: Chronic obstructive pulmonary disease (COPD) is a common comorbid disease in lung cancer. The prognostic significance of COPD preceding lung cancer diagnosis is still controversial and the magnitude of its impact remains unclear. The purpose of this study was to summarize and quantify the effect of preexisting COPD on overall survival of lung cancer patients.
Methods: A systemic literature research of PubMed database was performed to identify relevant and select qualified studies. The overall survival of lung cancer patients with or without COPD was compared. The pooled log (hazard ratio [HR]) and its standard error were calculated as outcome variables.
Results: A total of 16 studies were included. Overall, COPD was an adverse prognostic factor (HR, 1.22; 95%CI, 1.18-1.27), and the association remained significant in both Asians (HR, 1.33; 95%CI, 1.18-1.51) and Caucasians (HR, 1.21; 95%CI, 1.16-1.26). A stratified analysis showed the pooled HR was significant in non-small cell lung cancer (HR, 1.23; 95%CI, 1.16-1.30) or mixed types (HR, 1.16; 95%CI, 1.03-1.30) but not in small cell lung cancer (HR, 1.01; 95%CI, 0.87-1.17). Additionally, the pooled HR was significant in early stage lung cancer (HR, 1.35; 95%CI, 1.12-1.63) but not in late stage (HR, 1.08; 95%CI, 0.92-1.27). In patients treated with surgery, the presence of COPD was associated with approximately 30% worse survival (HR, 1.31; 95%CI, 1.13-1.51).
Conclusions: COPD has a deleterious impact on survival of lung cancer regardless of the ethnic groups studied. In addition, the impact appears to be more pronounced in patients with non-small cell lung cancer, at an early-stage, and who received surgical treatment.
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