Comparative outcomes of radical nephroureterectomy and kidney-sparing surgery in the treatment of high-grade upper tract urothelial carcinoma.

e16609 Background: Patients with upper tract urothelial carcinoma (UTUC) can be managed via radical nephroureterectomy (RNU) or kidney-sparing surgery (KSS) depending on pathology and patient characteristics. Unfortunately, UTUC is a rare disease lacking high-level evidence regarding clinical and oncologic outcomes after management. This study compares outcomes of RNU to KSS for high-grade (HG) UTUC. Methods: We retrospectively reviewed all patients with >1 year follow-up treated for HG UTUC at our institution from 2015-2021. Oncologic and clinical outcomes were recorded. Procedure burden was analyzed as total procedures under anesthesia, anesthesia time, days hospitalized, and estimated cost of care. Results: We identified 17 patients treated with KSS and 46 with RNU. There was no significant difference in 5-year overall survival, 3-year metastasis-free survival, or 3-year recurrence-free survival with KSS compared to RNU (Table). The average change in GFR was 17.9 ± 18.3 mL/min/1.73 m² and 24.8 ± 21.0 mL/min/1.73 m² for patients who underwent KSS and RNU, respectively (p = 0.33). Renal function was preserved (GFR decline <10 mL/min/1.73 m²) 2 years after surgery in 100.0% of patients who had KSS compared to 97.1% of patients who had RNU (p = 0.081). Patients who had KSS experienced a higher total number of procedures but fewer perioperative complications than those who had RNU with 3.4 ± 1.7 procedures vs 2.1 ± 1.7 procedures, respectively (p = 0.016), and 0% vs 41% of patients experiencing complications, respectively (p = 0.0098). Total anesthesia time and days hospitalized for KSS were similar to RNU at 400 ± 218 minutes vs 474 ± 185 minutes (p = 0.26) and 5.5 ± 4.3 days vs 6.8 ± 4.6 days, respectively (p = 0.36). Patients with KSS experienced a lesser in network but similar out of network cost of care to RNU patients at $7881 ± $4438 vs $10799 ± $4539 (p = 0.020) and $22159 ± $12401 vs $24523 ± $11282, respectively (p = 0.46). Conclusions: There were similar oncologic and clinical outcomes in HG UTUC patients treated with KSS or RNU. Patients treated with KSS endured a greater procedural load than patients who had RNU but at a reduced in network cost and with fewer complications. Larger datasets are needed to further evaluate outcomes and treatment burdens of RNU vs KSS as HG UTUC treatment. [Table: see text]