Accurate prognostic tools are essential for guiding therapeutic decisions and follow-up strategies in patients with urothelial bladder cancer undergoing radical cystectomy. Although decision tree models have shown promise in predicting cancer-specific outcomes, their clinical utility depends on external validation across diverse populations. This study aimed to externally validate a previously published decision tree model for predicting cancer-specific mortality using an independent multi-centre cohort from south-east Spain.
A multi-centre retrospective cohort study was conducted across five university hospitals in south-east Spain. A total of 553 patients with histologically confirmed urothelial bladder cancer who underwent standard radical cystectomy between 2004 and 2025 were included. A decision tree model originally developed using the Surveillance, Epidemiology, and End Results (SEER) database to predict cancer-specific survival was externally validated. The development and validation cohorts were comparatively analysed using chi-square tests and analysis of variance. Model discrimination was assessed using the concordance index (C-index) and calibration plots. Clinical utility was evaluated using decision curve analysis (DCA).
The C-index was 0.733 in the Spanish validation cohort, indicating good discriminative performance. DCA demonstrated a net benefit of using the model over a "treat-all" strategy at threshold probabilities >25%. Despite demographic and staging differences between the validation and original cohorts, the model maintained its predictive accuracy.
This study provides formal external validation of a decision tree model for predicting cancer-specific mortality after radical cystectomy, demonstrating robust performance and supporting its use in clinical settings in south-east Spain.
Archivos espanoles de urologia. 2026 May [Epub]
Pau Sarrio-Sanz, Jose Vicente Segura-Heras, Miriam Artés-Artés, Marina Belda-Ferre, Natalia Vidal-Crespo, Pedro Martinez-Meneu, Laura Martínez-Cayuelas, Helena Pérez-Seoane Ballester, Vicente Francisco Gil-Guillen, Luis Gómez-Perez, Manuel Angel Ortiz-Gorraiz
Urology Services, University Hospital of San Juan de Alicante, 03540 San Juan de Alicante, Spain., Instituto Centro de Investigación Operativa, Miguel Hernández University, 03203 Elche, Spain., Urology Services, University Hospital Reina Sofia, 30003 Murcia, Spain., Urology Services, University and General Hospital of Elche, 03540 Elche, Spain., Urology Services, University Clinic Hospital Virgen de la Arrixaca, 30003 Murcia, Spain., Urology Services, University General Hospital Castellón, 12004 Castellon, Spain., Clinical Medicine Department, Miguel Hernández University, 03540 San Juan de Alicante, Spain.