Neutrophil to lymphocyte ratio, PD-L1 expression, and survival in patients with advanced non-small cell lung cancer receiving first-line immune checkpoint inhibitor therapy.

Abstract

46 Background: Neutrophil to lymphocyte ratio (NLR) is known to be prognostic for patients with various types of cancer, including those who are treated with immune checkpoint inhibitors (ICI). We evaluated NLR at baseline and during early phase of treatment for patients with advanced non-small cell lung cancer (NSCLC) who received ICI to evaluate its prognostic value in first line ICI therapy and its relationship to programmed death-ligand 1 (PD-L1) expression. Methods: We retrospectively evaluated patients with advanced NSCLC who received ICI as first line therapy from 2016 to 2018. NLR was calculated as ratio of absolute neutrophil/lymphocyte counts and was consider elevated if ≥5. PD-L1 expression by immunohistochemistry was performed as standard of care with 22C3 antibody. Kaplan Meier analysis was used for survival. Wilcoxon-Mann-Whitney test was used to evaluate PD-L1 expression between groups. All Calculation was performed using SAS V9.4. Results: A total of 78 patients were included in this study; 28 received pembrolizumab monotherapy, 45 received pembrolizumab, carboplatin, and pemetrexed, and 5 received other pembrolizumab combinations. Patients with baseline NLR < 5 before initiating ICI had median estimated OS of 46.1 months (79.4% patient still alive and 95% CI not reached) compare to median OS of 10.7 months (95% CI lower limit 6.4 and upper limit not reached) for patients with NLR ≥5, P < 0.001. Similar association between NLR and OS can be seen when NLR were repeated immediate before the cycle 2 with P = 0.001. We observed an association between baseline NLR and PD-L1 expression. The median PD-L1 tumor proportion score (TPS) was 60% (Interquartile Range 1-80) for patients with baseline NLR < 5 vs 20% (IQR 0-60) for patients with NLR ≥5, P = 0.037. Conclusions: We confirmed the prognostic value of NLR for patients with advanced NSCLC at baseline and during early treatment in patients with NSCLC receiving first line ICI treatment. We also found an association between elevated NLR and lower PD-L1 expression. Future study with larger cohort is still needed to further delineate these relationships.