The Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival after radical cystectomy for urothelial carcinoma of the bladder: External validation in a cohort of Korean patients.

•Externally validated the Cancer of the Bladder Risk Assessment (COBRA) score to predict cancer-specific survival using Korean urothelial carcinoma of the bladder (UCB) patient cohort.•Compared with the American Joint Committee on Cancer staging system, The COBRA score showed a higher predictive accuracy, better calibration, and meaningful clinical net benefit.•Our results indicate the COBRA score can be served as a potential predictive tool for predicting survival outcomes after radical cystectomy in external UCB patients.