Prognostic value of the prognostic nutritional index for patients with renal cell carcinoma: an update systematic review and meta-analysis

OBJECTIVE: This study aimed to comprehensively evaluate the prognostic value of the prognostic nutritional index (PNI) for patients with renal cell carcinoma (RCC) through an updated systematic review and meta-analysis, providing reliable evidence for clinical practice. METHODS: Following the PRISMA 2020 guidelines, a systematic literature search was conducted across PubMed, Embase, Web of Science, and the Cochrane Database from inception to October 2025. Observational studies evaluating the association between PNI and overall survival (OS), progression-free survival (PFS), and cancer-specific survival (CSS) in patients with RCC were included. Two researchers independently screened the studies, extracted data, and assessed quality using the Newcastle-Ottawa Scale. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were pooled using a random-effects model. Heterogeneity was assessed using the Cochran’s Q test and the I² statistic. Publication bias was analyzed using the Egger’s test and the trim-and-fill method. RESULTS: A total of 14 studies, involving 7147 patients, were included. Meta-analysis showed that higher PNI was associated with significantly improved OS (HR = 0.43, 95% CI: 0.33–0.58, P < 0.00001), PFS (HR = 0.46, 95% CI: 0.35–0.61, P < 0.00001), and CSS (HR = 0.60, 95% CI: 0.45–0.79, P = 0.0003). Moderate to high heterogeneity was observed for OS and PFS (I²=63%-69%), but sensitivity analyses were robust. Publication bias testing revealed a slight bias in OS, and the results remained unchanged after trimming and filling adjustment. CONCLUSION: PNI is an independent prognostic factor for RCC patients, with higher PNI significantly associated with better survival outcomes. PNI integrates nutritional and inflammatory status and is a simple and low-cost clinical tool suitable for risk stratification and personalized management. Future prospective studies are needed to verify its clinical utility and optimize the cutoff criteria.