Purpose: To address the safety and feasibility of adjuvant single-dose upper urinary tract instillation of mitomycin (ASDM) immediately after therapeutic ureteroscopy for upper tract urothelial carcinoma (UTUC) and to compare urothelial (ipsilateral or bladder) recurrence rates in the ASDM group and controls. Materials and Methods: Between April 2015 and August 2018, 52 patients affected by UTUC were treated by endoscopic ablation, of whom 26 were selected for ASDM. Clinical and perioperative data and 30-day complications were recorded. Urothelial recurrence-free survival (URFS) was evaluated with second-look ureteroscopy (URS) and CT scan/URS every 6 months. Results: ASDM was administered through a Single-J (19/25, 76%) or a Double-J (6/25, 24%) in 25/26 (96%) patients. Median follow-up was 18 months (IQR 10-29). The urothelial recurrence rate was 23.5% and 55.5% in the ASDM group and controls, respectively (p = 0.086). Mean URFS was 28.8 months in the ASDM group vs 18.8 months in controls (log-rank p = 0.067). On multivariate Cox regression, ASDM was associated with a 7.7-fold lower risk of urothelial recurrence (HR = 0.13; 95% CI 0.03-0.65; p = 0.01). Clavien grade ≤II complications occurred in 32% (8/25) and 30.7% (8/26) of the ASDM and control group, respectively (p = 0.9). Two Clavien III complications occurred in the ASDM group: bladder hematuria after concomitant transurethral resection of bladder and obstructive kidney failure in a single-kidney patient. Conclusions: ASDM was well tolerated after therapeutic URS. It appears to reduce the risk of urothelial recurrence in patients affected by low-grade UTUC without bladder tumor. Therefore, its use should be evaluated.
Keywords: kidney-sparing surgery; mitomycin C; recurrence; topical chemotherapy; upper tract urothelial carcinoma.