Pleural neutrophil-to-lymphocyte ratio may be associated with early disease progression in stage IV non-small cell lung cancer

Background/Aim: While blood neutrophil-tolymphocyte ratio (NLR) has been associated with poor prognosis in NSCLC, however few studies have focused on pleural fluid white blood cell differential count. We conducted a retrospective multicenter cohort study to evaluate the predictive value of pleural NLR in non-small cell lung cancer (NSCLC) patients with malignant pleural effusion (MPE). Patients and Methods: From the multicenter lung cancer cohort, 134 epidermal growth factor receptor (EGFR) wild-type patients with NSCLC were selected for evaluation. Receiver operating characteristic (ROC) curve analysis was performed for pretreatment pleural NLR to determine the cut-off value for predicting disease progression within 100 days after the diagnosis. Results: The low-pleural NLR group showed significantly longer overall survival (OS) and progression free survival (PFS) compared to the high-pleural NLR group. After stratification using quartile cut-off values of pleural NLR, the correlation between risk of disease progression and pleural NLR was shown to be dose-dependent. The multivariate analysis on PFS showed that high-pleural NLR (p=0.004) was an independent predictor for shorter PFS with HR of 1.036 (1.011-1.061). Conclusion: Increased pleural NLR is predictive of early disease progression in EGFR mutation wild-type NSCLC patients with MPE.