Development of a Pocket Nomogram to Predict Cancer and Disease Specific Survival After Radical Cystectomy For Bladder Cancer: The CRAB Nomogram

Objectives: To develop an easy tool to predict cancer specific (CSS) and disease-free survival (DFS) in patients with bladder cancer treated with radical cystectomy.

Methods: Data from a consecutive series of 2395 patients with primitive or progression to muscle invasive bladder cancer (MIBC) undergone to radical cystectomy and lymph nodes dissection in 5 centers were evaluated. Using Cox proportional hazards analyses, the Cancer of the bladder risk assessment (CRAB) nomogram was generated. Accuracy of the nomogram was evaluated by Harrell's C test. Internal validation of the model was performed using 200 bootstraps.

Results: Median age was 66 (IQR 58/73) years; 612/2395 (26%) patients presented an advanced pathological stage (≥pT3a); 478/2395 (20%) presented positive lymph nodes. Overall, 729/2395 (30%) presented local or distant recurrence with a median DFS of 42 (IQR 14/89) months. Overall, 642/2395 (27%) died of bladder cancer with a median follow up of 48 (IQR 22/92) months. On univariate Cox proportional hazards analyses, age, stage, and lymph nodes density were a significant predictor of 3 and5 years CSS and DFS. Accuracy of the CRAB nomogram was 0.73 and 0.71 respectively.

Conclusion: CRAB nomogram can be a practical and easily applicable tool that may help urologists to classify the long-term CSS and DFS of patients treated with radical cystectomy and to predict the oncological outcome.