Prognostic Value of the Prognostic Nutritional Index in Patients with Metastatic Melanoma

Prognostic outcomes vary considerably among patients with metastatic melanoma. We examined the association of the prognostic nutritional index (PNI), neutrophil-to-lymphocyte ratio (NLR), and systemic immune-inflammation index (SII) with overall survival in this patient population.

We retrospectively evaluated 60 patients with metastatic melanoma treated at a single center. PNI was derived from serum albumin and absolute lymphocyte count. A cut-off of 52 was identified by ROC analysis and used to define the PNI groups. Overall survival was analyzed using the Kaplan-Meier method and Cox proportional hazards regression. PNI was entered into separate multivariable models with NLR or SII.

Overall survival was longer in patients with PNI ≥52 than in those with PNI <52 (log-rank p = 0.008). PNI, NLR, SII, and immunotherapy use were associated with OS in univariate Cox analysis. After multivariable adjustment, PNI remained significant in the model containing NLR (HR: 0.36, 95% CI: 0.15-0.85; p = 0.020) and in the model containing SII (HR: 0.37, 95% CI: 0.16-0.88; p = 0.024). Immunotherapy use was also independently associated with OS, whereas NLR and SII were not. PNI remained associated with OS when analyzed as a continuous variable (HR: 0.91, 95% CI: 0.84-0.98; p = 0.008). The AUC for PNI was 0.706 (95% CI: 0.551-0.833; p = 0.015).

Higher PNI was independently associated with longer overall survival in this cohort of patients with metastatic melanoma. These findings support further investigation of PNI as a readily available prognostic marker, although validation in larger independent cohorts is needed.