Nephrometry Scores: The Effect of Imaging on Routine Read-out and Prediction of Outcome of Nephron-sparing Surgery.

BACKGROUND/AIM: This study investigated the impact of available preoperative imaging on the reliability and predictive accuracy of RENAL and PADUA nephrometry-scoring systems for renal tumors. PATIENTS AND METHODS: Five urologists determined RENAL and PADUA scores using preoperative imaging data (computed tomography and magnetic resonance imaging) of 100 patients admitted for partial nephrectomy with the following combinations: T0: transverse planes without excretory phase (EP), TC0: transverse and coronal planes without EP, TC1: transverse and coronal planes with EP. Reference standard was obtained by a uro-radiologist. Ischemia time was used as surrogate for surgical complexity. RESULTS: Assignment of EP significantly reduced interobserver-variability among urologists (p<0.0001). Predictive accuracy for surgical complexity or correct assignment to nephrometry risk groups did not depend on image planes or EP. CONCLUSION: Interobserver variability, but not predictive accuracy of nephrometric systems, is affected by additional usage of EP.

Tumor size and invasiveness matters for partial nephrectomy: External validation and modification of the arterial based complexity score.

BACKGROUND: Outcome of partial nephrectomy (PN) depends on anatomic features of the renal tumor, which can be assessed by nephrometry scores. The aim was to externally validate and refine the Arterial Based Complexity (ABC) score and to compare it to established systems. METHODS: Tumors of 300 patients undergoing PN were categorized according to the ABC, RENAL, and PADUA score. Size and tumor invasiveness were combined to form the ABCD score. Correlation analysis and multivariate logistic regression was performed to validate and compare the respective scores as predictors of surgical outcome. RESULTS: The ABC score shows significant correlation with ischemia time (IT) (P < 0.01), opening of the collecting system (CS) (P < 0.01), and conversion to nephrectomy (P = 0.01). In the multivariate analysis, the ABC score was predictive for on-clamp excision (P < 0.01) and opening of the CS (P < 0.01) only. The RENAL and ABCD scores were independent predictors for complications (P = 0.02, P = 0.05), IT (P < 0.01, P = 0.03), on clamp excision (P < 0.01, P < 0.01), and opening of the CS (P < 0.01, P < 0.01). CONCLUSIONS: The ABC score correlates well with surgical parameters. Expanding the score by tumor diameter gives the ABCD system. It has similar predictive effectiveness to the well-established RENAL score, but features simplicity by only assessing invasiveness and tumor size.