The Simplified PADUA REnal (SPARE) nephrometry system: a novel classification of parenchymal renal tumours suitable for partial nephrectomy

Abstract

Objective To simplify the original Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) classification of renal tumours, generating a new system able to predict equally or better the risk of overall complications in patients undergoing partial nephrectomy (PN); and to test if the addition of the contact surface area (CSA) parameter improves the accuracy of the original PADUA and new Simplified PADUA REnal (SPARE) nephrometry classification systems. Patients and Methods We analysed the clinical records of 531 patients who underwent PN (open, laparoscopic and robot‐assisted) for renal tumours at five tertiary academic referral centres 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 SPARE classification. In addition to the original PADUA and SPARE systems, another two models were generated adding tumour CSA. Receiver operating characteristic curve analysis was used to compare the ability of the four different 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 estimated glomerular filtration rate (eGFR; ACE). Results The SPARE nephrometry score system including: (i) rim location, (ii) renal sinus involvement, (iii) exophytic rate, and (iv) tumour dimension; showed equal performance in comparison with the original PADUA score (area under the curve [AUC] 0.657 vs 0.664). Adding tumour CSA to the original PADUA (AUC 0.661) or to the SPARE (AUC 0.658) scores did not increase the accuracy of either system to predict overall complications. The SPARE system (odds ratio 1.2, 95% confidence interval 1.1–1.3) was an independent predictor of postoperative overall complications. Age (P < 0.001), body mass index (P < 0.001), Charlson Comorbidity Index (P = 0.02), preoperative eGFR (P < 0.001), and tumour CSA (P = 0.005) were independent predictors of ACE. Limitations include the retrospective design and the lack of central imaging review. Conclusions The new SPARE score is comprised of only four variables instead of the original six and its accuracy to predict overall complications is similar to that of the original PADUA score. Addition of tumour CSA was not associated with an increase in prognostic accuracy. The SPARE system could replace the original PADUA score to evaluate the complexity of tumours suitable for PN.

Comparison of the RENAL, PADUA, DAP, NePhRO, and SPARE scores for retroperitoneal laparoscopic partial nephrectomy.

“…The SPARE score is less involved and may be easier to calculate than the PADUA score. Nevertheless, the ability of the SPARE score to predict complications in PN is similar to that of the PADUA score 15 .…”

“…20 The SPARE score may re ect the trend of score development. The SPARE scoring system streamlines the elements of the score, removing the less consistent elements of the polar location and removing the involvement of the UCS, which is di cult to determine 15 . In most previous nephrometry scoring systems, the assignment is usually 1, 2, or 3.…”

“…Images were reviewed electronically by experienced urologists, and the morphological features of the tumors were identi ed and evaluated according to established criteria. 8,9,10,11,15 Then, scores were generated according to the tumor features observed. Each patient's American Society of Anesthesiologists (ASA) score, WIT, OT, EBL, and postoperative complications were obtained from the original operation data and electronic medical records.…”

“…From RENAL to the latest ABC 14 and SPARE 15 scoring systems, these systems are constantly being optimized. 16 These scoring systems are widely used and were designed with open or transperitoneal operations in mind.…”

Assessment of Complexity of Organ preserving Surgery of Kidney Tumors, Systems and Scales of Nephrometry

“…Міждисциплінарна угода між урологами та рентгенологами може бути додатково розширена за допомогою нової спрощеної версії класифікації PADUA, нещодавно запропонованої Ficarra et al Спрощена нефрометрична система PADUA REnal (SPARE) не включає два показники оцінки оригінальної системи PADUA, щодо оцінки полярного розташування пухлини та ураження верхньої частини збиральної системи нирки, що є найбільш складними крокам у калькуляції балів [38]. Зараз проводяться перспективні дослідження для оцінки цієї системи.…”