Clinical Characteristics and Risk Factors for Recurrence or Progression of Pediatric Intracranial Pilocytic Astrocytoma: A Single-center Retrospective Study

Objective To identify risk factors for recurrence or progression in pediatric intracranial pilocytic astrocytoma (PA) and develop a prognostic model for 5-year progression-free survival (PFS). Methods This retrospective study included patients under 18 diagnosed with PA (2010–2024). Variables with P < 0.1 in univariate analysis were entered into multivariate Cox modeling, with the final model selected by bidirectional stepwise selection using the lowest Akaike information criterion (AIC). Model performance was assessed by concordance index (C-index), time-dependent receiver operating characteristic (ROC) curves, time-dependent area under the curve (AUC), calibration curves, and decision curve analysis (DCA). Internal validation was performed by bootstrapping, and a nomogram was constructed for risk stratification. Kaplan-Meier (K-M) and log-rank tests were used to compare survival outcomes. Results Seventy-two patients were included. Age ≤ 3 years (HR = 0.13, P = 0.02), supratentorial tumor location (HR = 7.69, P = 0.02), and Ki-67 ≥ 5% (HR = 16.42, P < 0.001) were independent predictors of recurrence/progression. The model showed excellent discrimination (C-index = 0.92; bootstrap-corrected = 0.89) and good calibration. Time-dependent AUCs at 1, 3, and 5 years were 0.906, 0.911, and 0.911, respectively. The nomogram showed that Ki-67 contributed the greatest prognostic weight, followed by age and tumor location. Patients with higher total scores (> 158.76) had significantly shorter 5-year PFS. Conclusions This nomogram may assist clinicians in estimating postoperative prognosis in children and adolescents with PA. It provides a foundation for future studies incorporating larger cohorts and molecular markers, and may help identify high-risk patients even after gross total resection (GTR).