Pulmonary function is implicated in the prognosis of metastatic non-small cell lung cancer but not in extended disease small cell lung cancer

Background: The impacts of pulmonary function in patients with metastatic non-small cell lung cancer (NSCLC) and extended disease stage small cell lung cancer (SCLC-ED) treated with palliative chemotherapy remain to still be determined. Methods: Results of spirometry performed in 449 patients with either stage IV NSCLC (n=313) or SCLC-ED (n=136) at diagnosis were reviewed retrospectively. Overall survival (OS) was estimated using the Kaplan-Meier method and compared via a log-rank test. Multivariate analysis was performed using a Cox proportional hazards regression model. Results: The presence of chronic obstructive pulmonary disease (COPD) was not a risk factor for OS in either NSCLC or SCLC. However, NSCLC patients with COPD with a forced expiratory volume in one second (FEV1) value of less than 80% predicted were associated with a worse OS in both univariate and multivariate analyses [hazard ratio (HR): 1.43; 95% confidence interval (CI): 1.04–1.97; P=0.03]. Intriguingly, only the OS of NSCLC patients treated with chemotherapeutic agents was affected by the airflow limitation FEV1 value of less than 80% predicted (P=0.02). Patients with an FEV1 value of less than 80% predicted treated with targeted agents were not associated with OS (P=0.24). On the other hand, NSCLC patients with COPD were significantly linked to the occurrence of pulmonary complications during palliative therapy (P=0.01) but not associated with death resulting from pulmonary complications (P=0.22). Conclusions: Careful attention is required when chemotherapeutic agents are administered to patients with metastatic NSCLC with accompanying COPD with a FEV1 value of less than 80% predicted.