Prognostic significance of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) in untreated and treated stage IV non-small cell lung cancer (NSCLC): An Australian cancer centre experience.

Abstract

e20630 Background: Baseline high NLR predicts poorer outcome in stage IV NSCLC; post-treatment variation in NLR and potential impact on overall survival (OS) is not clear in this group. Prognostic implications of PLR and LMR are not well studied for stage IV NSCLC. We aimed to assess the prognostic role of NLR, LMR and PLR in stage IV NSCLC at diagnosis and post-treatment. Methods: A retrospective descriptive study of 279 patients with Stage IV NSCLC treated at our centre over five year period (2010 to 2015). NLR, PLR and LMR calculated at diagnosis and post first cycle chemotherapy/targeted treatment. Demographic variables summarized. Estimates of Kaplan-Meier survival distributions for OS were generated. Cox regression used to derive OS hazard ratios of predictive variables. Approval from ethics committee obtained. Results: Baseline NLR, PLR and LMR showed strong association with OS. A five-unit increase at baseline (treatment start date) in NLR was associated with an 11% increase in the hazard of death (HR = 1.115, 95% CI: 1.077-1.148) while the same increase in PLR was associated with 0.5% increase in the hazard of death (HR = 1.005, 95% CI:1-1.005). A five-unit increase in LMR at baseline was associated with a 50% reduction in the hazard of death (HR = 0.50, 95% CI:0.260-0.956). Post-treatment NLR, PLR and LMR were examined in 221 patients. Fitted models incorporating adjustment for baseline values demonstrated that increasing NLR correlated with a shorter OS (HR = 1.574, 95% CI:1.295-1.917) but no statistically significant relationship could be demonstrated for PLR nor LMR. Conclusions: While NLR, PLR and LMR showed significant associations with OS prior to treatment, only NLR showed an association with OS after treatment. OS was shorter for high NLR and high PLR at baseline compared to low NLR and low PLR at baseline. OS was longer for high LMR at baseline compared to low at baseline. An increase in NLR post-treatment correlated with a shorter OS. This is the first study examining the prognostic significance of all three ratios in patients with untreated and treated stage IV NSCLC.