Defining Renal Masses: Comprehensive Comparison of RENAL, PADUA, NePhRO, and C-Index Score

doi:10.1016/j.clgc.2016.07.029

Clinical Genitourinary Cancer

Volume 15, Issue 2, April 2017, Pages 248-255.e1

https://doi.org/10.1016/j.clgc.2016.07.029 Get rights and content

Abstract

Background

Nephrometry scores are designed for standardized reporting of renal tumors and predicting complications. Multiple scores are available, but there is a lack of systematic comparison.

Patients and Methods

A total of 305 consecutive patients admitted for open partial nephrectomy to 2 urological hospitals were prospectively assessed. Five cases with conversion to radical nephrectomy were excluded from further analysis. RENAL, PADUA, C-index, and NePhRO scores were obtained from preoperative sectional imaging. Additionally, interobserver variance between 2 urologists and a radiologist was analyzed for 50 patients. Linear and ordered logistic regression was used to evaluate the association between scores and surgical parameters. Receiver operating characteristic analysis was employed to assess the predictive value for requirement of ischemia and opening of the collecting system.

Results

High interobserver agreement was observed for RENAL (0.92 and 0.80), PADUA (0.81 and 0.85), NePhRO (0.94 and 0.82), and the C-index (0.98 and 0.95). All scores showed a significant association with opening of the collecting system (P < .016), requirement of on-clamp excision (P < .001), and ischemia time (P < .001). Logistic regression identified RENAL, PADUA, and NePhRO score to be an independent predictor for severe complications (P = .016, P = .011, and P = .005). No correlation was found for the C-index (ß = 0.98; P = .779). Predictive effectiveness for opening of the collecting system and for on-clamp excision showed comparable area under the curve values for the 4 scores.

Conclusion

All scoring systems represent objective and reproducible measurement tools for renal tumor complexity, that correlate well with surgical outcome. RENAL, PADUA, and NePhRO score are comparable and seem to be superior to the more complex C-index system.

Introduction

Over the past decades, the incidental diagnosis of renal tumors has increased due to the growing use of modern imaging modalities.¹ Partial nephrectomy (PN) has emerged as the therapy of choice for small renal masses. It should be given preference over radical nephrectomy if technically possible.2, 3

To improve risk stratification of renal masses prior to nephron-sparing surgery (NSS), anatomy-based nephrometry scores (NScs) have been developed.⁴ They allow standardized reporting of renal tumors and measure surgical complexity regarding the important anatomical aspects of a renal mass.4, 5 Because different NScs correlate well with key surgical parameters such as ischemia time (IT), complications, or blood loss. they play an important role in clinical assessment and comparison within clinical trials and studies.⁵ NSc measurements have consequently become an important part of studies on NSS.5, 6

To this day, more than 10 different NScs have been published.⁴ The majority of these tools aim to predict surgical complexity and overall complications.⁴ A major drawback in nephrometry is the availability and use of various scores, limiting the transfer and reproducibility of findings.⁶ Whereas some scores did not attract broad interest by being too complex or inaccurate, there are still a handful of well-established scores that have already proven a good performance in measuring tumor complexity, leaving urologists with a difficult choice.4, 7 Among these is the RENAL score, which was introduced as the first NSc by Kutikov and Uzzo, followed by the PADUA score and the C-index score. Whereas for determining the RENAL and PADUA scores, points for different anatomical aspects are assigned and added, the C-index measures the ratio of the tumor size and the distance between the center of the kidney to the center of the renal mass.8, 9, 10 In 2014, the NePhRO score was published as a simple and superior NSc, and was validated with promising results.11, 12 These scores have been validated successfully for predicting outcome of PN; however, respective studies show inconsistent results.6, 13, 14 There is still a lack of systematic comparisons of the predictive value for clinical outcome of the existing NScs.

The aim of this study was to provide a comprehensive comparison of the RENAL, PADUA, C-index, and NePhRO scores. The respective tools were compared regarding their interobserver agreement as well as their significance in prediction of the surgical outcome of open PN.

Section snippets

Study Design and Data Collection

We included 305 consecutive patients admitted for open partial nephrectomy (OPN) to 2 urological clinics (University Medical Center, Mannheim [n = 240] and Urological Clinic Munich-Planegg [n = 65]) between 2013 and 2015. We prospectively collected patients' characteristics, histopathologic findings, and surgical outcome. Postoperative complications were assessed using the Clavien classification with a follow-up of a minimum of 30 days.¹⁵ Furthermore, complications were classified into

Results

Table 1 shows demographic data and surgical outcome of the study population. OPN was successfully performed in 300 patients, whereas in 5 patients, intraoperative conversion to radical nephrectomy was required. These 5 cases were excluded from further analysis. Median patient age was 65 years (interquartile range [IQR], 55-74 years) with an average body mass index of 26.6 kg/m² (IQR, 24.2-29.7 kg/m²). The median tumor size was 32 mm (IQR, 2.3-4.5 mm), and 77.3% (n = 236) of the tumors were

Discussion

The characterization of renal masses has changed over the last years. Size alone has been shown to not sufficiently describe the surgical complexity of a kidney tumor.9, 20 On this account, NScs have been introduced to enable comparative and reproducible descriptions of the anatomy of renal masses and to standardize reports on surgical complexity of NSS.4, 5

To date, more than 10 different nephrometry scoring systems have been introduced.⁴ The availability of various NScs can be a drawback in

Disclosure

The authors have stated that they have no conflicts of interest.

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Cited by (33)

Nephrometric scoring system: Recent advances and outlooks
2023, Urologic Oncology: Seminars and Original Investigations
A nephrometry scoring system is a key standard to evaluate the feasibility of partial nephrectomy (PN). Whether based on two-dimensional or three-dimensional images, simplicity, effectiveness, and practicality are the keys to the nephrometric scoring system. Since the emergence of RENAL score in 2009, numerous scoring systems based on different anatomical parameters are established to seek accurately and few parameters to assess the risk of PN and complications. This study aimed to achieve a three-game winning streak in PN more easily and efficiently (negative resection margin, maximum preservation of normal nephron function, and avoiding short-term and long-term complications). Using PubMed, we counted 28 kinds of nephrometric scoring systems. We considered only English literatures published and excluded editorials, commentaries, and meeting abstracts. To the best of our knowledge, this is to date and most comprehensive summary as well as an outlook of the nephrometric scoring system.
Novel Volumetric and Morphological Parameters Derived from Three-dimensional Virtual Modeling to Improve Comprehension of Tumor's Anatomy in Patients with Renal Cancer
2022, European Urology Focus
Three-dimensional (3D) models improve the comprehension of renal anatomy.
To evaluate the impact of novel 3D-derived parameters, to predict surgical outcomes after robot-assisted partial nephrectomy (RAPN).
Sixty-nine patients with cT1-T2 renal mass scheduled for RAPN were included. Three-dimensional virtual modeling was achieved from computed tomography. The following volumetric and morphological 3D parameters were calculated: V_T (volume of the tumor); V_T/V_K (ratio between tumor volume and kidney volume); CSA_3D (ie, contact surface area); UCS_3D (contact to the urinary collecting system); Tumor-Artery_3D: tumor’s blood supply by tertiary segmental arteries (score = 1), secondary segmental artery (score = 2), or primary segmental/main renal artery (scoren = 3); S_T (tumor’s sphericity); Conv_T (tumor’s convexity); and Endophyticity_3D (ratio between the CSA_3D and the global tumor surface).
RAPN with a 3D model.
Three-dimensional parameters were compared between patients with and without complications. Univariate logistic regression was used to predict overall complications and type of clamping; linear regression was used to predict operative time, warm ischemia time, and estimated blood loss.
Overall, 11 (15%) individuals experienced overall complications (7.2% had Clavien ≥3 complications). Patients with urinary collecting system (UCS) involvement at 3D model (UCS_3D = 2), tumor with blood supply by primary or secondary segmentary arteries (Tumor-Artery_3D = 1 and 2), and high Endophyticity_3D values had significantly higher rates of overall complications (all p ≤ 0.03). At univariate analysis, UCS_3D, Tumor-Artery_3D, and Endophyticity_3D are significantly associated with overall complications; CSA_3D and Endophyticity_3D were associated with warm ischemia time; and CSA_3D was associated with selective clamping (all p ≤ 0.03). Sample size and the lack of interobserver variability are the main limits.
Three-dimensional modeling provides novel volumetric and morphological parameters to predict surgical outcomes after RAPN.
Novel morphological and volumetric parameters can be derived from a three-dimensional model to describe surgical complexity of renal mass and to predict surgical outcomes after robot-assisted partial nephrectomy.
Improving Accuracy, Reliability, and Efficiency of the RENAL Nephrometry Score With 3D Reconstructed Virtual Imaging
2022, Urology
To clarify the diagnostic performance of the three-dimensional reconstructed virtual image (3D-RVI) in evaluating RENAL nephrometry score (RENAL-NS).
This study included 130 patients who underwent preoperative contrast-enhanced computed tomography followed by partial nephrectomy for renal tumors suggestive of renal cell carcinoma. RENAL-NS was calculated prior to the surgery, and tumor resection was performed referring to the score. We retrospectively reviewed preoperative contrast-enhanced computed tomography images. We calculated the inter-observer variability of RENAL-NS using 3D-RVI vs two-dimensional (2D) imaging and compared the ability of RENAL-NS using 3D-RVI vs 2D imaging to predict the risk of opening of the urinary collecting system. We also compared the two modalities for the time required to evaluate RENAL-NS.
RENAL-NS evaluated using 3D-RVI showed a higher inter-observer agreement compared to 2D-imaging (r_s = 0.85 vs r_s = 0.65). The “nearness to sinus” score was more strongly associated with the opening of the urinary collecting system when evaluated using 3D-RVI than 2D-imaging (AUC = 0.71 vs AUC = 0.57, P = .016). RENAL-NS using 2D-imaging required a significantly longer time compared to 3D-RVI (P = .036).
Using 3D-RVI improves the accuracy, reliability and efficiency of RENAL-NS evaluation in preoperative assessment and can play an important role in preoperative assessment and intraoperative navigation.
Can Aortic and Renal Arteries Calcium Scores Be New Factors to Predict Post-Operative Renal Function After Nephron Sparing Surgery?
2022, Clinical Genitourinary Cancer
This study aims to investigate whether the calcification of renal arteries and aorta may be risk factors for developing chronic kidney disease (CKD) after Nephron sparing surgery (NSS).
The patients that underwent either open or laparoscopic NSS from 2000 to 2019 in 4 different centers were retrospectively assessed. Of these patients, 328 had a non-contrast-enhanced computer tomography.
Calcium scores of the renal arteries and abdominal aorta were measured in the non-contrast-enhanced images with the calcium score plugin (version 2.0) of Horos™. Univariate and multivariate logistic regression analysis was performed to determine significant risk factors for developing CKD at the last check-up. Roc curve analysis was performed to determine the optimal cut-off values of age and abdominal aorta calcium scores.
A total of 302 patients, of which 52 (16,6%) with CKD and 252 (83,4%) without CKD at the last check-up, were included in the analysis. The mean warm ischemia duration was significantly higher in patients with CKD (18,79±6,72 vs 16,38±5,57 minutes, p=0,016). The mean size of the tumor diameter and the number of the patients with ≥stage T1b were higher in the group with CKD (p=0,024 and 0,005, respectively). The median calcium scores of the aorta and renal arteries were higher in the group with CKD (p<0,001 and p<0,001, respectively). In multivariate analysis, age >60 years (OR:3,65, p=0,022), calcium score of the aorta (OR:4,07, p=0,029), tumor diameter (OR:1,03, p=0,026) and pre-operative CKD stage (OR:10,13, p<0,001) found the be significant factors for predicting last check-up CKD.
The calcium score of the aorta may be used as an additional risk factor to predict post-operative CKD risk after NSS with sensitivity over 80%.
Omission of Cortical Renorrhaphy During Robotic Partial Nephrectomy: A Vattikuti Collective Quality Initiative Database Analysis
2020, Urology
To analyze the outcomes of patients in whom cortical (outer) renorrhaphy (CR) was omitted during robotic partial nephrectomy (RPN).
We analyzed 1453 patients undergoing RPN, from 2006 to 2018, within a large multi-institutional database. Patients having surgery for bilateral tumors (n = 73) were excluded. CR and no-CR groups were compared in terms of operative and ischemia time, estimated blood loss (EBL), complications, surgical margins, hospital stay, change in estimated glomerular filtration rate (eGFR), and need of angioembolization. Inverse probability of treatment weighting with Firth correction for center code was performed to account for selection bias.
CR was omitted in 120 patients (8.7%); 1260 (91.3%) patients underwent both inner layer and CR. There was no difference in intraoperative complications (7.4% CR; 8.9% no-CR group; P = .6), postoperative major complications (1% and 2.8% in CR and no-CR groups, respectively; P = .2), or median drop in eGFR (7.3 vs 10.4 mL/min/m²). The no-CR group had a higher incidence of minor complications (26.7% vs 5.5% in CR group; P < .001). EBL was 100 mL (IQR 50-200) in both groups (P = .6). Angioembolization was needed in 0.7% patients in CR vs 1.4% in no-CR group (P = .4). Additionally, there was no difference in median operative time (168 vs 162 min; P = .2) or ischemia time (18 vs 17 min; P = .7).
In selected patients with renal masses, single layer renorrhaphy does not significantly improve operative time, ischemia time, or eGFR after RPN. There is a higher incidence of minor complications, but not major perioperative complications after no-CR technique.
Predictive Value of Nephrometry Scores in Nephron-sparing Surgery: A Systematic Review and Meta-analysis
2020, European Urology Focus
Citation Excerpt :
The first-generation nephrometry scores showed once again their predictive role of overall complications as both continuous and categorical variables. Kriegmair et al [76] achieved the same result in a large cohort series comparing four different scores. Interestingly, the authors analyzed NePhRO score and C-index, with the first related to complications (p = 0.011).
Over the last decade, several nephrometry scores (NSs) have been introduced with the aim of facilitating preoperative decision making, planning, and counseling in the field of nephron-sparing surgery. However, their predictive role remains controversial.
To describe currently available nephrometry scores and to determine their predictive role for different outcomes by performing a systematic review and meta-analysis of the literature.
PubMed, Embase®, and Web of Science were screened to identify eligible studies. Identification and selection of the reports were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). A pooled analysis of NS predictive role of intraoperative, postoperative, oncological, and functional outcomes was performed. Odds ratio was considered the effect size. All the analyses were performed using Stata 15.0, and statistical significance was set at p ≤ 0.05.
Overall, 51 studies meeting our inclusion criteria were identified and considered for the analysis. Except for one prospective randomized trial, all the studies were retrospective. All the studies were found to be of intermediate quality, except for one of high quality. Most studies assessed the predictive role of the Radius-Exophytic/Endophytic-Nearness-Anterior/Posterior-Location (RENAL) and Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) scores, mostly regarding complications after nephron-sparing surgery. RENAL was an independent predictor of an on-clamp procedure (p < 0.001). Mayo Adhesive Probability score was related to adhesive perinephric fat (p = 0.005). Continuous and high-complexity RENAL scores were predictors of warm ischemia time (WIT; p = 0.006 and p < 0.001, respectively). Continuous (p < 0.001) and high-complexity (p < 0.001) PADUA scores were related to WIT. Continuous and high-complexity RENAL scores were predictors of overall complications (p = 0.002 and p < 0.001, respectively). PADUA score was related to complications both as continuous (p < 0.001) and as a categorical value (p < 0.002). The RENAL scores R = 3 (p = 0.008), E = 2 (p = 0.039), and hilar location (p = 0.006) were predictors of histological malignancy. Continuous and categorical RENAL scores were independent predictors of an estimated glomerular filtration rate (eGFR) increase (p = 0.006 and p < 0.001, respectively). The Diameter-Axial-Polar score (p = 0.018) and Peritumoral Artery Scoring System (PASS; p = 0.02) were also independent predictors.
The literature regarding nephrometry scoring systems is sparse, and mostly focused on RENAL and PADUA, which are easy to calculate and have a good correlation with most outcomes. Renal Pelvic Score is the best predictor of pelvicalyceal entry/repair and urine leak, whereas Surgical Approach Renal Ranking and PASS strongly predict surgical approach and renal function variation, respectively. Other nephrometry scores based on mathematical models are limited by their complexity, and they lack evidence supporting their predictive value.
We reviewed the medical literature regarding the use and value of so-called “nephrometry scores,” which are scoring systems based on radiological imaging and made to grade the complexity of a renal tumor. We analyzed whether these scoring systems can predict some of the outcomes of patients undergoing surgical removal of renal tumors.

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: N.W. and D.P. contributed equally to this article.

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Original StudyDefining Renal Masses: Comprehensive Comparison of RENAL, PADUA, NePhRO, and C-Index Score

Abstract

Background

Patients and Methods

Results

Conclusion

Introduction

Section snippets

Study Design and Data Collection

Results

Discussion

Disclosure

Eur Urol

Urology

Eur Urol

Eur Urol

J Urol

Eur Urol

J Urol

Clin Genitourin Cancer

Eur Urol

J Urol

J Urol

Urology

J Urol

J Urol

J Urol

Original Study
Defining Renal Masses: Comprehensive Comparison of RENAL, PADUA, NePhRO, and C-Index Score