Association of baseline neutrophil-to-lymphocyte ratio and prognosis in melanoma patients treated with PD-1/PD-L1 blockade: a systematic review and meta-analysis

Immunotherapy treatments that target programmed cell death receptor-1 (PD-1) or its ligand (PD-L1) have revolutionized the treatment of metastatic melanoma and currently represent the standard first-line treatment for this type of cancer. However, it is still not entirely clear which biomarkers are cost-effective, simple, and highly reliable. This systematic review and meta-analysis aims to analyze the predictive value of the baseline neutrophil-lymphocyte ratio (NLR) regarding disease progression and overall survival of patients with metastatic melanoma undergoing treatment with PD-1/PD-L1 blockade. PubMed, Scopus, and Web of Science were searched for studies comparing high versus low NLR. We performed the meta-analysis using RStudio v4.4.2 software. A total of 20 studies and 2691 patients were included, all with diagnoses of melanoma. The majority of the individuals were male 2278 (84, 65%). The median overall survival (OS) and progression-free survival (PFS) ranged from 5.0 to 44.4 and from 1.8 to 15.0 months, respectively. Compared with the high NLR ratio, the low exposure group achieved better rates of OS [hazard ratio (HR), 2.07; 95% CI, 1.73-2.48; P < 0.00001; I² = 47%]. Regarding PFS, there was a statistically significant difference between groups with tendencies toward the low NLR exposure group (HR, 1.59; 95% CI, 1.39-1.81; P < 0.00001; I²=31%]. This systematic review and meta-analysis revealed significant lower OS in melanoma patients treated with PD-1/PD-L1 blockade who had elevated baseline NLR values. Furthermore, an increased PFS was observed in patients with a lower baseline NLR value. This study highlights NLR as an important prognostic biomarker for patients with metastatic melanoma who are candidates for treatment with PD-1 and PD-L1.