Narrative review discusses eosinophil abundance associations with lung cancer prognosis and immunotherapy response

This narrative review synthesizes evidence regarding eosinophil abundance in tumor tissues and peripheral blood within the context of lung cancer. The scope encompasses anti-tumor immunity, tumor progression, prognostic outcomes, and response to immune checkpoint inhibitors. The authors do not report specific sample sizes, settings, or follow-up durations for the included data sources.

Key findings indicate that eosinophil abundance is associated with both favorable and unfavorable prognostic outcomes. Specifically, elevated eosinophil counts correlate with improved responses to immune checkpoint inhibitors. However, the review notes that effect sizes, absolute numbers, and p-values are not reported in the source material. The direction of association for general prognostic outcomes is not specified beyond the dualistic nature of the findings.

Significant limitations are acknowledged by the authors. Distinctions between tumor-infiltrating and circulating eosinophils remain incompletely understood. Additionally, the dualistic roles of eosinophils in metastasis and immune modulation remain incompletely understood. These gaps suggest that the evidence base is not yet definitive for clinical application.

Regarding practice relevance, the review underscores the promise of eosinophils as diagnostic and therapeutic targets in precision immuno-oncology. Clinicians should note that the authors advise against inferring causation from association. No adverse events or safety data were reported in this review.