Real-world Feasibility of Adjuvant Nivolumab for High-risk Upper Tract Urothelial Carcinoma After Radical Nephroureterectomy.

BACKGROUND/AIM: Adjuvant nivolumab is an important postoperative option for high-risk muscle-invasive urothelial carcinoma, but upper tract urothelial carcinoma (UTUC)-specific real-world evidence remains limited. This study evaluated oncologic outcomes, feasibility, and safety of adjuvant nivolumab after radical nephroureterectomy in patients with high-risk UTUC. PATIENTS AND METHODS: We retrospectively analyzed 21 consecutive patients with high-risk UTUC who received adjuvant nivolumab at the Kansai Medical University group between April 2022 and March 2025. Metastasis-free survival (MFS), overall survival (OS), treatment completion, and treatment-related adverse events (AEs) were assessed. Survival was estimated using the Kaplan-Meier method. RESULTS: The median age was 76 years, and 14 patients (66.7%) had received neoadjuvant chemotherapy. The median follow-up from nivolumab initiation was 744 days. Median MFS and OS were not reached. The 12- and 24-month MFS rates were both 80.1%, while the 12- and 24-month OS rates were 90.0% and 84.4%, respectively. The median treatment duration was 34 weeks, and 10 patients (47.6%) completed the planned 48-week course. Any treatment-related AE occurred in nine patients (42.9%), and seven discontinued treatment because of grade 3 AEs. CONCLUSION: This early real-world study suggests that adjuvant nivolumab is feasible and may provide favorable short-term disease control in selected patients with high-risk UTUC after radical nephroureterectomy. These findings support its potential role as a postoperative option for selected patients, particularly when delivery of additional platinum-based therapy is difficult.