Development and Validation of a Neutrophil Percentage-to-Albumin Ratio-Based Nomogram for Predicting Overall Survival in Locally Advanced Nasopharyngeal Carcinoma

Purpose: Hematology-based inflammatory-nutritional composite indices are robust prognostic biomarkers for malignancies due to their survival correlation. This study explored the prognostic value of the neutrophil percentage-albumin ratio (NPAR) - a composite marker reflecting systemic inflammation and nutrition - in locally advanced nasopharyngeal carcinoma (LA-NPC), whose predictive role in LA-NPC survival remains underexplored. Patients and Methods: A retrospective study of 536 LA-NPC patients who received definitive radiotherapy at Guangxi Medical University Cancer Hospital was conducted. Patients were randomized into training (n=321, 60%) and validation (n=215, 40%) cohorts via the `sample()` function in R. NPAR and other continuous variables were dichotomized using optimal cut-offs from the `survminer` package in R. Kaplan-Meier and Log-rank analyses compared survival; least absolute shrinkage and selection operator (LASSO) regression identified key prognostic parameters, with univariate and multivariate Cox regression confirming independent survival factors. A prognostic nomogram was built from these factors, and its predictive efficacy was evaluated via calibration curves (accuracy), Harrell's C-index (discrimination), time-dependent receiver operating characteristic (tROC) curves, and decision curve analysis (DCA; clinical utility). Results: Multivariate Cox regression for overall survival (OS) in the training cohort identified NPAR, age, TNM stage, pretreatment EBV DNA level, and hypertension as independent prognostic factors for LA-NPC. A nomogram integrating these five variables was constructed. Calibration curves, C-index, tROC curves, and DCA confirmed that the nomogram accurately predicted 3- and 5-year OS probabilities, with high consistency between predicted and observed outcomes. Furthermore, the nomogram outperformed the 8th edition TNM staging system in terms of predictive performance, as evidenced by superior C-index, tROC, and DCA results. Conclusion: NPAR, an accessible routine blood-based hematological biomarker, is a promising prognostic indicator for LA-NPC. The nomogram integrating NPAR and key clinical parameters enables more accurate personalized treatment stratification, facilitating precision management and yielding translational potential for improved LA-NPC outcomes.