Distinct Predictors of Early Postoperative and Long-Term Renal Function Decline Following Radical Nephroureterectomy for Upper Tract Urothelial Carcinoma.

OBJECTIVES: This study aimed to evaluate early postoperative and long-term changes in renal function following radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC) and to identify factors associated with each phase. METHODS: We retrospectively reviewed 168 patients who underwent RNU for UTUC between 2007 and 2022. Renal function was assessed using estimated glomerular filtration rate (eGFR). Early postoperative renal function decline (RFD) was defined as the percentage decrease in eGFR from preoperative values to 1 month post-surgery. Factors associated with early postoperative RFD were evaluated using multivariable linear regression analyses. Long-term RFD was assessed using serial eGFR measurements obtained from 1 month after surgery onward and was analyzed with multivariable linear mixed-effects models. RESULTS: The median follow-up period was 74.5 months. The median preoperative eGFR and early postoperative RFD were 53.1 mL/min/1.73m2 and 30.4%, respectively. Multivariable analysis demonstrated that lower clinical stage, absence of hydronephrosis, absence of neoadjuvant chemotherapy, and a preoperative eGFR ≥ 45 mL/min/1.73 m2 were independently associated with greater early postoperative RFD. Overall renal function remained relatively stable following the initial postoperative decline. Multivariable analysis identified hypertension and preoperative proteinuria as independent predictors of progressive long-term RFD. Patients with both hypertension and proteinuria experienced greater long-term RFD compared to those with zero or one risk factor. CONCLUSIONS: Predictors of early postoperative RFD differed from those of progressive long-term RFD following RNU. These findings suggest that early and long-term postoperative renal functional changes may need to be considered separately in clinical decision-making and patient counseling.