Metachronous Contralateral Recurrence in Upper Tract Urothelial Carcinoma: A Multi-Institutional Competing-Risks Analysis From the ROBUUST 3.0 Registry.

INTRODUCTION

The purpose of this study was to define the incidence and predictors of metachronous contralateral recurrence in upper tract urothelial carcinoma and develop a risk score for tailored surveillance.

METHODS

We analyzed 3024 patients surgically treated with curative intent from a multi-institutional registry (ROBUUST 3.0). A composite risk score assigned 1 point each for prior bladder cancer, tumor multifocality, and estimated glomerular filtration rate at discharge < 60 mL/min/1.73 m2. Patients were stratified into low (0 points), intermediate (1-2 points), and high (3 points) risk. Cumulative incidence was estimated using competing-risks regression models, accounting for death and distant metastasis and internally validated using a cause-specific proportional hazards model.

RESULTS

Twenty patients (0.7%) developed contralateral recurrence over a median 26.5 months. Recurrence was significantly associated with prior bladder cancer (80% vs 31.5%, P < .001), tumor multifocality (55% vs 20%, P = .001), and lower estimated glomerular filtration rate at discharge (39 vs 48 mL/min/1.73 m2, P = .01). Three-year cumulative incidence rates were 0.7% (low risk), 0.9% (intermediate risk), and 10.5% (high risk; P < .001). High-risk patients faced an estimated 17-fold increased hazard vs low-risk patients. The model demonstrated excellent discriminative accuracy (Concordance Index 0.81).

CONCLUSIONS

Contralateral recurrence is rare but heavily dependent on prior bladder cancer, multifocality, and impaired renal function. Our internally validated risk score accurately stratifies patients, facilitating surveillance de-escalation for low-risk individuals and intensive monitoring for high-risk patients.