Prognostic role of the baseline neutrophil‒eosinophil ratio in cancer patients: a meta-analysis and systematic review.

BACKGROUND

Inflammation impacts the prognosis of numerous types of tumors. Inflammatory indicators such as the neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and neutrophil-to-eosinophil ratio (NER) have emerged as potential prognostic markers and are closely correlated with the outcomes of cancer patients. However, the connection between NER and cancer prognosis remains incompletely understood. Therefore, we conducted a meta-analysis to investigate the potential of the inflammatory marker NER as a prognostic indicator in cancer patients.

METHODS

A thorough search was conducted across PubMed, Embase, Web of Science, and the Cochrane Library, with a cutoff date of August 2024. Relevant data were extracted, and hazard ratios (HRs) and relative risks (RRs), along with their corresponding 95% confidence intervals (CIs), were calculated to assess the prognostic impact of the NER on overall survival (OS), progression-free survival (PFS), and the objective response rate (ORR). Stata version 18 statistical software was utilized for the meta-analysis of the literature that met the inclusion criteria.

RESULTS

Seven cohort studies encompassing a total of 1,336 cancer patients were included in this meta-analysis. These findings indicate that lower NER is associated with improved PFS in cancer patients. Additionally, in cancer patients undergoing immunotherapy, lower NER levels are linked to a better ORR. A lower NER is correlated with improved OS and ORR in patients with metastatic renal cancer who are receiving immunotherapy.

CONCLUSION

In cancer patients, elevated NER is associated with poorer PFS and ORR. Similarly, high NER levels in patients with metastatic renal cell carcinoma undergoing immunotherapy are linked to worse OS and ORR. The inflammatory marker NER, which serves as an efficacious prognostic indicator for cancer patients, offers profound insights into related cancers in the context of immunotherapy. In the future, high-quality prospective studies are warranted to corroborate these findings.