Complications following repeated ureteroscopy for <scp>UTUC</scp> : The price to pay for nephron‐sparing surgery

Objective To evaluate the safety profile of, and identify predictors of complications in patients undergoing, endoscopic conservative upper tract urothelial carcinoma (UTUC) management at a high‐volume tertiary centre. Methods We retrospectively reviewed 67 patients treated conservatively for UTUC, undergoing a total of 268 ureteroscopy (URS) procedures (2015–2025). Complications were collected via chart review and patient interviews from the first URS to last follow‐up and graded according to the Clavien–Dindo classification. Univariable logistic regression was used to assess predictors of complications and ureteral stenosis (US). Cumulative incidence plots depicted time‐to‐complication events. Renal function was evaluated using serial estimated glomerular filtration rate measurements and analysed through individual trajectories and locally estimated scatterplot smoothed trends. Results The median number of URS per patient was three (interquartile range 2–5). At least one complication occurred in 32 patients (47%). Clavien–Dindo I–II and IIIa‐b events accounted for 87% and 13% of complications, respectively. Twelve patients (18%) developed endoscopic evidence of US; of these, three (25%) were treated endoscopically and two (16%) ultimately required radical nephroureterectomy. The 5‐year cumulative incidence of any and major complications (Clavien–Dindo ≥ 3) was 62% (95% confidence interval 43–75) and 14% (95% confidence interval 2–25), respectively. On univariable analysis, the number of URS was the only variable significantly associated with both any complication (odds ratio 1.41 per URS, P = 0.012) and US (odds ratio 1.20 per URS, P = 0.042). The predicted risk of US reached 22.7% after six URS. Over 50 months, mean estimated glomerular filtration rate declined by &gt;20 mL/min/1.73 m 2 in the overall cohort, whereas the mean decline was limited to ~10 mL/min/1.73 m 2 in patients who did not undergo RNU or require intervention for US or hydronephrosis. Conclusions Conservative management of UTUC is associated with a cumulative risk of mostly low‐grade complications. Prolonged endoscopic follow‐up may increase the likelihood of US in a subset of patients. These findings support informed patient counselling and individualized surveillance planning.