Introduction: Nephrotoxicity from platinum-based neoadjuvant and adjuvant chemotherapy for upper tract urothelial carcinoma (UTUC) must be considered in the context of definitive surgical timing. We developed a predictive nomogram for eGFR estimation after radical nephroureterectomy (RNU) using a multi-institutional cohort to aid with decisions regarding sequencing of nephrotoxic chemotherapy before or after surgery. Methods: Patients undergoing RNU for UTUC from 2000-2020 were included. Patients with solitary kidney, prior cystectomy, or neoadjuvant chemotherapy were excluded. eGFR values were normalized using the CKD-EPI equation. Patients were randomly allocated 2:1 into test and validation sets. Test data were used to identify covariates independently associated with eGFR 1-3 months after RNU using univariable linear regression. Backward selection was applied for model construction, including all variables with p<0.05 on multivariable linear regression in the nomogram. The nomogram was then subjected to validation. Pearson coefficients assessed correlation between observed and predicted post-RNU eGFR. Results: 1095 patients were included in analysis. Median eGFR pre-operatively and 1-3 months post-RNU was 60.0 and 43.3mL/min/1.73m2, respectively. Significant independent predictors of eGFR post-RNU in the test cohort included age (-0.28, 95% CI -0.37;-0.19), diabetes (-2.53, 95% CI -4.61;-0.46), tumor size (1.02, 95% CI 0.58;1.46) and pre-RNU eGFR (0.4, 95% CI 0.35;0.45). The nomogram (Fig. 1) exhibited R=0.71 (95% CI 0.65,0.76; Figure 2) in the validation set with 80% accuracy (% predicted eGFR values within 30% of observed). Conclusions: We generated a nomogram to predict post-RNU renal function with moderate accuracy using independent predictors of eGFR change after RNU. These data can be used in patient counseling to better personalize the sequencing of nephrotoxic chemotherapy in the neoadjuvant and adjuvant settings in a risk-stratified approach. SOURCE OF Funding: Urology Care Foundation Research Scholars Award to PJH (IRG 85-001-25), Monteleone Family Foundation for Research in Bladder and Kidney Cancer and the Eleanor and Scott Petty Fund for Upper Tract Urothelial Carcinoma Research (SFM).
