Prognostic nutritional index and survival outcomes in cervical cancer: an updated systematic review and meta-analysis

Cervical cancer is one of the most common malignancies among women globally. The Prognostic Nutritional Index (PNI) has been widely explored in cervical cancer studies, but its prognostic value has remained inconsistent across studies. This meta-analysis aimed to explore the prognostic significance of PNI in cervical cancer. PubMed, Embase, Web of Science, and the Cochrane Library were searched from inception to July 13, 2025. Studies analyzing the association between PNI and clinical outcomes were retrieved. The main outcomes were overall survival (OS) and progression-free survival (PFS). A random-effects model was used to calculate pooled hazard ratios (HRs) along with their 95% confidence intervals (CIs). Sensitivity and subgroup analyses were performed to assess robustness and identify potential sources of heterogeneity. This analysis included 17 studies, which were divided into 22 independent cohorts with 5,007 patients. Pooled multivariate-adjusted HRs showed that lower PNI was significantly associated with worse OS (HR = 1.57, 95% CI: 1.37–1.79) and PFS (HR = 1.53, 95% CI: 1.29–1.82). Significant heterogeneity was observed for both OS and PFS (OS: I² = 79%; PFS: I² = 72%). Subgroup analysis suggested that age, study region, sample size, and PNI cut-off value were the primary sources of heterogeneity. In the single study conducted in India and in studies with a PNI cut-off value < 48, the association between PNI and PFS was not statistically significant. Low PNI was significantly associated with poor OS and PFS in cervical cancer patients. A PNI cut-off value ≥ 48 was associated with prognostic outcomes and may serve as a preliminary reference for clinical risk stratification. However, this finding is exploratory. Due to heterogeneity, publication bias, and residual confounding factors, the independent prognostic value of PNI should be interpreted with caution. Large-scale, multi-center prospective studies are needed to further validate the prognostic value of PNI across different populations and to explore its standardized cut-off value.