Diagnostic ureteroscopy prior to nephroureterectomy for urothelial carcinoma is associated with a high risk of bladder recurrence despite technical precautions to avoid tumor spillage.

Bladder recurrence after diagnostic ureteroscopy + nephroureterectomy was high despite technical precautions to avoid contact of bladder mucosa with contaminated urine from the upper urinary tract. Post-DFU endovesical instillation should be investigated.