Pre-treatment NLR and Changes in NLR Are Associated With Survival Following the Initiation of Immune Checkpoint Inhibitor Therapy in Patients With Non-small Cell Lung Cancer

Background/Aim: The pre-treatment neutrophil/lymphocyte ratio (NLR) has been associated with survival after the initiation of immune checkpoint inhibitor (ICI) therapy. However, information regarding a change in NLR after ICI therapy is scarce. We conducted this retrospective study to investigate the association between a change in NLR and outcomes in patients with non-small cell lung cancer (NSCLC) who were treated with ICI therapy. Patients and Methods: Data on patients with NSCLC who were treated with ICI therapy, including PD-1/PD-L1 antibody monotherapy and combination therapy with cytotoxic agents or CTLA-4 antibody between 2017 and 2023, were analyzed. Pre-treatment NLR and the change in NLR following treatment initiation were evaluated. Pre-treatment NLR was measured within 14 days before the day of treatment initiation and compared with that measured 56 days (±14 days) after treatment initiation. Results: A total of 121 patients were included in the study. The Cox proportional hazards model revealed that a pre-treatment NLR of ≥5 (p=0.019) and an increase in NLR following treatment initiation (p=0.006) were independently associated with the risk of progression. Conversely, a tumor PD-L1 expression level of ≥50% (p=0.033) was associated with a reduced risk of progression. Multiple logistic regression analysis showed that the concomitant use of cytotoxic agents (p=0.029) was associated with a decrease in NLR and that liver metastases (p=0.014) were associated with an increase in NLR. Conclusion: Pre-treatment NLR and a change in NLR were associated with progression-free survival after the initiation of ICI therapy. Furthermore, concomitant use of cytotoxic agents and liver metastases may be associated with a change in NLR.