The prognostic impact of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio on patients with small cell lung cancer receiving first-line platinum-based chemotherapy: a systematic review and meta-analysis

The prognostic significance of Neutrophil-to-Lymphocyte Ratio (NLR) and Platelet-to-Lymphocyte Ratio (PLR) in Small Cell Lung Cancer (SCLC) patients receiving platinum-based chemotherapy is debated.

This study aims to elucidate their roles in survival outcomes. A systematic search across PubMed, Embase, Web of Science, and Cochrane Library identified relevant studies. The Newcastle-Ottawa Scale (NOS) evaluated study quality. Meta-analysis was conducted using random-effects and fixed-effects models, supplemented by sensitivity analysis.

A total of 11 studies with 3,634 SCLC patients were included. Patients with high NLR had significantly decreased overall survival (OS) (HR = 1.39, 95% CI: 1.18–1.59, P < 0.001) and progression-free survival (PFS) (HR = 1.52, 95%CI: 1.27–1.78, P < 0.001). The OS was not statistically different between high and low PLR groups (HR = 1.13, 95%CI: 0.84–1.43, P = 0.265). Subgroup analysis revealed that OS in high NLR group was significantly lower across different strata, and OS in the high PLR group was significantly lower among patients with limited-stage SCLC (LS-SCLC) and populations with a PLR cutoff value < 160.

High NLR is associated with poor OS and PFS in patients with SCLC receiving first-line platinum-based chemotherapy. PLR does not significantly impact OS, except in LS-SCLC patients and populations with a PLR cutoff value < 160. These findings require further validation from prospective studies.