Prognostic significance of pretreatment neutrophil-to-lymphocyte ratio in older patients with metastatic cancer.

Background: Treatment options for older patients with malignancies remain suboptimal. An accurate prognostic stratification could inform treatment decisions, which can potentially improve patient outcomes. Here, we sought to investigate whether the neutrophil-to-lymphocyte ratio (NLR) may have prognostic significance in patients with metastatic malignant tumors, with a special focus on older individuals.

Methods: We retrospectively reviewed the clinical records of 3981 patients with histology-proven metastatic cancer who underwent radiotherapy between 2000 and 2013. The pretreatment NLR was determined within 7 days before treatment initiation. Patients aged ≥65 years were considered as older. We analyzed the prognostic significance of NLR for overall survival (OS) across all age groups.

Results: Compared with their younger counterparts, older patients showed a higher NLR (P < 0.001) and a lower OS (P < 0.001). Multivariate analysis revealed that a pretreatment NLR below the median was an independent favorable predictor of OS in both older (hazard ratio [HR]: 0.669, 95.0% CI: 0.605-0.740; P < 0.001) and younger patients (HR: 0.704; 95.0% CI: 0.648-0.765; P < 0.001). Regardless of age, patients who underwent systemic therapy showed more favorable OS, especially when NLR was low. In the older subgroup, the OS of patients with a low pretreatment NLR who did not undergo systemic therapy and of those with high pretreatment NLR who underwent systemic therapy was similar.

Conclusion: A low pretreatment NLR predicts a more favorable OS in older patients with metastatic cancer. The most favorable OS was observed in patients with a low pretreatment NLR who received systemic therapy.