Evaluation of the Neutrophil-Based Inflammatory Indexes SIRI and NHR in Patients with Extensive-Stage Small Cell Lung Cancer Receiving First-Line Immune Checkpoint Inhibitors Plus Chemotherapy.

Abstract

Objective: To determine the predictive value of two neutrophil-based inflammatory indexes - the systemic inflammatory response index (SIRI) and the neutrophil-to-high density lipoprotein ratio (NHR) - in extensive-stage small cell lung cancer (ES-SCLC) patients treated with first-line immune checkpoint inhibitors (ICIs) and chemotherapy.

Methods: From May 2020 to May 2023, we enrolled 101 ES-SCLC patients receiving first-line ICIs and chemotherapy in this study. Clinicopathological features, haematological indicators including the SIRI and NHR, treatment efficacy, and patient outcome data were analyzed.

Results: There was no statistically significant difference in efficacy or outcome among enrolled patients receiving programmed cell death protein 1 (PD-1) or programmed cell death ligand 1 (PD-L1) inhibitors. The baseline SIRI (P=0.136) and NHR (P=0.453) did not perform well in predicting treatment response. The serum SIRI before treatment was not significantly different from that after two treatment cycles (P=0.113). After two treatment cycles, the serum NHR exhibited a significant decrease from its pretreatment value (P=0.004). The dynamics of the serum SIRI and NHR before therapy and at disease progression did not significantly differ (all P>0.05). The median progression-free survival (mPFS) and median overall survival (mOS) of patients were significantly longer in the high-SIRI group than in the low-SIRI group (mPFS: 7.033 vs. 5.900 months, P=0.020; mOS: 16.233 vs. 11.200 months, P=0.012). Moreover, patients in the low-NHR subgroup presented significantly longer mPFS and mOS than did those in the high-NHR subgroup (mPFS: 7.033 vs. 4.900 months, P=0.002; mOS: 13.933 vs. 8.500 months, P=0.006). Finally, multivariate analyses revealed that Eastern Cooperative Oncology Group performance status, the pretreatment serum SIRI, and the pretreatment serum NHR (all P<0.050) can serve as valuable independent predictors for PFS and OS in patients with ES-SCLC.

Conclusions: The baseline serum SIRI and NHR can serve as promising indicators of prognosis, but not treatment response, in ES-SCLC patients receiving first-line ICIs and chemotherapy.