Abstract
BACKGROUND: Several nephrometry scores have been proposed and applied in the adult population. We previously established a novel model to predict the feasibility of nephron-sparing surgery (NSS) in pediatric bilateral Wilms tumor (WT) patients. This study aimed to evaluate whether our model had better predictive performance compared to other scores. METHODS: Data from 58 patients during the period 2008-2019 were retrospectively reviewed. Nephrometry scores, including RENAL [radius (R), exophytic/endophytic (E), nearness to collecting system/sinus (N), anterior/posterior (A), and location relative to polar lines (L)], PADUA (preoperative aspects and dimensions used for an anatomical classification), and SPARE (Simplified PADUA REnal) scores, were calculated. A senior radiologist and a senior urologist independently reviewed computed tomography (CT) or magnetic resonance scans while blinded to clinical outcomes. A urology resident re-evaluated the imaging scans using our RSR [relation with collecting system (R), size (S), remaining renal parenchyma (R)] model. The areas under the curve (AUCs) were compared. Inter-rater reliability of the RSR model was assessed using kappa statistics and intraclass correlation coefficient (ICC). RESULTS: The AUC was 0.982 for the RSR model, which outperformed the other three scores. Decision curve analysis (DCA) showed the same results. Compared to the RENAL score, the RSR model showed significant reclassification ability [0.573 (95% confidence interval: 0.161, 1.204), P=0.03]. Significant overall discrimination ability was found with RSR compared to the other three scores (P<0.001). The ICC value was 0.871 for S, and the kappa values of the two R indicators were 0.806 and 0.777, respectively. A web-based calculator was constructed. CONCLUSIONS: The RSR model's predictive performance outperforms the established adult nephrometry scores while offering overall fair interobserver agreement. A web-based calculator could help to make personalized treatment decisions.