Nephrometry systems provide important information for treatment planning, patient counseling and comparison between different partial nephrectomy (PN) series. RENAL and PADUA classification are the most popular and widely used nephrometry systems. Objective of the study are: (1) to simplify the original PADUA classification of renal tumors generating a new system able to predict equally or better the risk of overall complications in patients undergoing PN; and (2) to test if the addition of contact surface area (CSA) parameter improves the accuracy of the original and new simplified PADUA classification.
We analyzed the clinical records of 531 patients who underwent PN (open, laparoscopic and robot-assisted) for renal tumours at 5 tertiary academic referral centers from January 2014 to December 2016. The ability of each variable included in the PADUA classification to predict overall complications was tested using binary logistic regression analysis. The variables that were not statistically significant were excluded from the simplified classification. Starting from original and simplified PADUA systems, another two models were generated adding tumor CSA. ROC curve analysis was used to compare the ability of the different 4 models to predict overall complications. Binary logistic regression was used to perform both univariable and multivariable analyses looking for predictors of postoperative complications. Linear regression analysis was used to identify independent predictors of absolute change in eGFR (ACE).
The Simplified PAdua REnal nephrometry (SPARE) score system including 1) rim location; 2) renal sinus involvement; 3) exophytic rate and 4) tumor dimension showed equal performance in comparison with the original PADUA score (AUC 0.657 Vs 0.664). Adding tumor CSA to the original (AUC 0.661) or to the simplified (AUC 0.658) PADUA scores did not increase the accuracy of both systems to predict overall complications. The SPARE system (OR 1.2 - 95%CI 1.1-1.3) was an independent predictor of postoperative overall complications. Age (p<0.001), BMI (p<0.001), Charlson index (p=0.02), preoperative eGFR (p<0.001), and tumor CSA (p=0.005) were independent predictors of ACE. Limitations include the retrospective design and the lack of central imaging review.
The SPARE score is composed by only 4 variables instead of the original six and its accuracy to predict overall complications is similar to that of the original PADUA score. Addition of tumor CSA was not associated with an increase in prognostic accuracy. The SPARE system could replace the original PADUA score to evaluate the complexity of tumors suitable for PN. This article is protected by copyright. All rights reserved.
BJU international. 2019 Apr 09 [Epub ahead of print]
Vincenzo Ficarra, Francesco Porpiglia, Alessandro Crestani, Andrea Minervini, Alessandro Antonelli, Nicola Longo, Giacomo Novara, Gianluca Giannarini, Cristian Fiori, Claudio Simeone, Marco Carini, Vincenzo Mirone
Department of Human and Pediatric Pathology "Gaetano Barresi", Urologic Section, University of Messina, Italy., Division of Urology, San Luigi Gonzaga Hospital Orbassano, University of Turin, Italy., Urology Unit, "Santa Maria Regina degli Angeli" Hospital, Adria (Ro), Italy., Department of Urology, Careggi Hospital, University of Florence, Italy., Urology Unit, ASST, Spedali Civili di Brescia, University of Brescia, Italy., Department of Urology, University of Federico II of Naples, Italy., Department of Oncologic, Surgical and Gastrointestinal Sciences, Urologic Unit, University of Padua, Italy.