Purpose <p>Upper tract urothelial carcinoma developing after radical cystectomy presents a technical challenge because complete ureteral removal to the ileal anastomosis is often hindered by postoperative adhesions. This study evaluated the prognostic impact of the completeness of ureteral excision including the ileal cuff in patients undergoing nephroureterectomy for upper tract recurrence after radical cystectomy.</p> Methods <p>We retrospectively analyzed 30 patients who underwent nephroureterectomy for recurrent upper tract urothelial carcinoma after radical cystectomy between 2001 and 2024. Patients were divided into the Cuff group (complete ureteral excision including the ileal cuff, <i>n</i> = 18) and the Cuff_Fail group (failed or omitted distal excision, <i>n</i> = 12). Survival outcomes were compared using Kaplan–Meier analysis, and Firth’s penalized Cox regression was applied to adjust for small-sample bias.</p> Results <p>Among 2,148 patients who underwent radical cystectomy, 30 (1.4%) later required nephroureterectomy for upper tract recurrence after a median interval of 49 months. The 5-year cancer-specific survival rate was significantly higher in the Cuff group than in the Cuff_Fail group (74.3% versus 30.6%, <i>p</i> = 0.013). Multivariate analysis identified incomplete ureteral removal as an independent predictor of poorer cancer-specific survival (hazard ratio 3.41; 95% confidence interval 1.09–12.32; <i>p</i> = 0.035).</p> Conclusion <p>In nephroureterectomy for upper tract recurrence after radical cystectomy, complete ileal cuff excision was associated with improved cancer-specific survival. These hypothesis-generating findings require validation in larger multi-center cohorts.</p>