Reproducibility and Fidelity of the R.E.N.A.L. Nephrometry Score

Parallel comparison of R.E.N.A.L., PADUA, and C-index scoring systems in predicting outcomes after partial nephrectomy: A systematic review and meta-analysis

Objective

To parallelly compare the applicability of the radius, exophytic/endophytic, nearness, anterior/posterior, location nephrometry score (R.E.N.A.L.), the Preoperative Aspects and Dimensions Used for an Anatomical (PADUA), and the centrality index (C‐index) scoring systems in predicting clinical outcomes after partial nephrectomy (PN).

Methods

We searched EMBASE, PubMed, Ovid, and Web of Science to perform a meta‐analysis examining the correlation coefficients between three nephrometry scores (NSs) and warm ischemia time (WIT), estimated blood loss (EBL), operation time (OT), length of stay (LOS), and absolute change in eGFR (ACE) up to 25 January 2021.

Results

In total, 13 studies including 1496 patients met the criteria for further analysis. Overall, all scoring systems had statistically significant correlations with the WIT, EBL, OT, ACE and LOS and ACE, except for the correlation between PADUA and LOS (r = 0.16 [−0.00, 0.31], p > 0.05). The C‐index had the strongest correlation with WIT (r = −0.35 [−0.43, −0.26], p < 0.05) and ACE (r = −0.29 [−0.48, −0.10], p < 0.05). Weak correlations were observed between OT as well as EBL and each scoring system. Publication bias was observed in PADUA score predicting ACE (p = 0.04) and high heterogeneity was found in some of our results.

Conclusion

Until now, this is the first meta‐analysis that parallelly compares these three scoring systems in predicting outcomes after PN. We found that all NSs showed a statistically significant correlation with WIT, EBL, OT, and ACE. Moreover, the C‐index scoring system is the best predictor of WIT and ACE. Due to the existence of publication bias and high heterogeneity, more well‐designed and large‐scale studies are warranted for validation.

To our knowledge, this is the first meta‐analysis that parallelly compares these three scoring systems in predicting outcomes after PN. Overall, three scoring systems were significantly correlated with WIT, EBL, OT and ACE. Moreover, the C‐index scoring system outperformed R.E.N.A.L. and PADUA scoring systems in WIT and ACE.

Modified R.E.N.A.L nephrometry score for predicting the outcome following partial nephrectomy

Background

It was difficult to compare the outcome of partial nephrectomy among different studies due to the absence of standardized description of different renal masses. This problem led to the development of nephrometry scoring systems. R.E.N.A.L. is among the commonest nephrometry scoring systems; however, some studies failed to find any relation between R.E.N.A.L. with perioperative outcome. We evaluated our designed newly modified nephrometry score in prediction of outcome following partial nephrectomy and compared its predictability versus original R.E.N.A.L.

Methods

Fifty-one patients with cT1-2N0M0 renal masses amenable for partial nephrectomy were included prospectively. Different perioperative outcome variables were compared according to complexity level in R.E.N.A.L. and the newly modified nephrometry score.

Results

Clinical staging was T1a (21.6%), T1b (49%), T2a (25.5%), T2b (3.9%). Median R.E.N.A.L. was 9 (4–12). Hilar position and intrarenal pelvis were detected in 19.6% and 68.6%. Low, moderate and high complexity masses were found in 21.6%, 39.2% and 39.2%. Complications and rate of conversion to radical nephrectomy were 17 (33.3%) and 4 (7.8%). The only significantly affected variable (p = 0.039) by R.E.N.A.L. was rate of secondary intervention, but it was higher in low than in high complexity level. In the newly modified nephrometry score, complications (p = 0.037) and rate of positive surgical margin (p = 0.049) were significantly higher with increased complexity level. Although other variables (pelvi-calyceal system entry, operative time, blood loss, hemoglobin loss, blood transfusion and conversion to radical nephrectomy) did not show statistically significant difference according to both scores, they were better associated with the complexity level in the newly modified nephrometry score with their remarkable increase in the high when compared to the low complexity level.

Conclusions

The newly modified nephrometry score was associated with better prediction of outcome of partial nephrectomy when compared to R.E.N.A.L.

Interobserver Reliability of the RENAL Nephrometry Scoring System: Experience From a Developing Nation

Introduction

The RENAL (radius, exophytic/endophytic properties, nearness of tumor to the collecting system or sinus in millimeters, anterior/posterior, location relative to polar lines) nephrometry score (RENAL-NS) has been described as a structured and quantifiable method to describe a renal tumor’s relevant anatomic features as they relate to the complexity of the lesion. We aim to evaluate a tumor’s RENAL-NS and to assess the reproducibility of the score among different observers.

Methods

This retrospective study included 49 patients diagnosed with renal cell carcinoma (RCC) who had complete computed tomography (CT) data, RENAL-NS, and histopathology results. All patients underwent renal surgery/intervention at our center between January 2008 and December 2018. The radius of the lesion, exophytic/endophytic properties, nearness to the collecting system, anterior or posterior description, and location relative to the polar lines was used to calculate the score. Tumor complexity was graded as low, intermediate, or high. Two body imaging radiologists evaluated the data independently.

Results

Interobserver agreement for each of the RENAL-NS parameters, respectively, and overall complexity was calculated. The total agreement was 82%, 51%, 84%, 69%, 73%, and 90%, corresponding to Kappa values of 0.72, 0.33, 0.44, 0.49, 0.58, and 0.83, respectively. The radius, nearness to the collecting system, and total complexity showed the best agreement. Exophytic properties of the lesion showed the least agreement. For cases that were discordant in terms of the final score, no major implications in surgical planning were observed.

Conclusion

The results of this study show that the RENAL-NS is a useful tool to assess the anatomical features of renal tumors and it is easily reproducible, even for less experienced radiologists in a developing nation.

Interobserver Agreement of the Estimated Contact Surface Area System for Renal Masses

BACKGROUND

Nephrometry scores have been designed to assist in standardization of renal masses before nephron-sparing surgery. Estimated contact surface area (eCSA) has been recently described. However, its reproducibility between raters has not been rigorously explored. Our aim was to examine the reproducibility of eCSA and Radius, Exophytic, Nearness, Anterior, Line (RENAL) score (RS) nephrometry systems for renal masses by studying the interobserver agreement between 4 raters.

MATERIALS AND METHODS

We reviewed the cross-sectional images (computed tomography, magnetic resonance imaging) of patients who underwent nephron-sparing surgery (open, laparoscopic, and robotic). Four urologists independently scored the renal tumors according to the eCSA and RS systems. Scoring was done separately for each nephrometry system. Interobserver agreement was assessed for total scores and separate components of each system by calculating the intraclass correlation coefficient (ICC).

RESULTS

Ninety patients were scored to achieve power of 83% with α = 0.05. eCSA and RS demonstrated excellent interobserver agreement (ICC = 0.89 for both). The radius component of eCSA and RS had the highest ICC (0.97 and 0.9, respectively) compared with the other components. Location and anterior/posterior components of RS showed poor interobserver correlation (ICC = 0.69 and 0.50, respectively). Maximal difference in RS complexity group assignment was 1 of 43 (47.8%) of cases.

CONCLUSION

eCSA has excellent interobserver agreement, similar to RS. Directly measurable anatomic variables have better interobserver correlation compared with qualitative variables. These results strengthen the applicability of eCSA as a surgical complexity metric for renal surgery.

DDD score for renal tumor: An intuitive and comprehensive anatomical scoring system to access the outcomes of retroperitoneal laparoscopic partial nephrectomy

OBJECTIVE

To present a DDD scoring system in assessing the complexity and outcomes of retroperitoneoscopic nephron-sparing surgery for kidney tumor.

METHODS

We retrospectively evaluated 232 patients who underwent retroperitoneoscopic nephron-sparing surgery between January 2013 and September 2017 for a renal tumor. Both the DDD score and RENAL score were used to classify the tumors. The DDD score consisted of the maximal tumor diameter inside the kidney, the maximal tumor depth into the medulla or collecting system and the minimal distance from the tumor to the main renal vessels.

RESULTS

The DDD scoring systems were significantly associated with warm ischemia time (P = 0.007) and estimated blood loss (P = 0.017). There was an insignificant positive correlation between the DDD score and the operative time (P = 0.051). Meanwhile, the RENAL score had a significant correlation with the decreasing value of the estimated glomerular filtration rate. Patients with high or moderate DDD scores had a 13.6-fold or 8.4-fold risk of overall complications than those with low DDD scores, respectively (all P < 0.05). As for RENAL score, patients with moderate scores had a 2.9-fold risk of overall complications compared with patients in the low scores group (P = 0.004). In the receiver operating characteristic curve analysis, the DDD score had the greatest area under the curve for overall complications (area under the curve 0.625, P = 0.009), which was more than the RENAL score (area under the curve 0.620, P = 0.013).

CONCLUSIONS

The DDD score is an intuitive renal tumor scoring system that is more effective than the RENAL score in complexity assessment, and marginally better in prediction of the risk of overall complications of retroperitoneal laparoscopic nephron-sparing surgery.

Comparison of RENAL, PADUA, and C-index scoring systems in predicting perioperative outcomes after nephron sparing surgery

Introduction and Objective

The RENAL, PADUA and centrality index (C-index) nephrometry scoring systems (SS) have been individually evaluated for their role in predicting trifecta outcomes after nephron-sparing surgery (NSS). However, there is little data on their comparative superiority. The present study was designed to evaluate the predictive value of three SS and to assess interobserver reliability.

Materials and Methods

Fifty patients undergoing NSS at our center between January 2014 and April 2016 were included in the study. The demographic details were noted. Images (computed tomography [CT] scans or magnetic resonance imaging) were reviewed by a urologist and a radiologist independently and RENAL, PADUA, and C-index were calculated. The correlation between these scoring system and trifecta outcomes were calculated.

Results

The RENAL and PADUA score did not correlate with any of the perioperative parameters. However, C-index had a significant correlation with operative time (OT) (P = 0.02) and trifecta outcomes (P < 0.05). There was an excellent concordance between the two observers in scoring the RENAL score (α = 0.915; intraclass correlation coefficient [ICC] = 0.814) and PADUA score (α = 0.816; ICC = 0.689 [P < 0.001]). There was lesser although acceptable concordance in the calculation of C-index (ICC -0.552; α -0.711).

Conclusions

There is good correlation among all the 3 SS. C-index has lower reproducibility due to difficult mathematical calculation but correlated best with trifecta outcomes.

Obesity as defined by waist circumference but not body mass index is associated with higher renal mass complexity

OBJECTIVES

Obesity, typically defined as a body mass index (BMI)≥30kg/m², is an established risk factor for renal cell carcinoma (RCC) but is paradoxically linked to less advanced disease at diagnosis and improved outcomes. However, BMI has inherent flaws, and alternate obesity-defining metrics that emphasize abdominal fat are available. We investigated 3 obesity-defining metrics, to better examine the associations of abdominal fat vs. generalized obesity with renal tumor stage, grade, or R.E.N.A.L. nephrometry score.

METHODS AND MATERIALS

In a prospective cohort of 99 subjects with renal masses undergoing resection and no evidence of metastatic disease, obesity was assessed using 3 metrics: body mass index (BMI), radiographic waist circumference (WC), and retrorenal fat (RRF) pad distance. R.E.N.A.L. nephrometry scores were calculated based on preoperative CT or MRI. Univariate and multivariate analyses were performed to identify associations between obesity metrics and nephrometry score, tumor grade, and tumor stage.

RESULTS

In the 99 subjects, surgery was partial nephrectomy in 51 and radical nephrectomy in 48. Pathology showed benign masses in 11 and RCC in 88 (of which 20 had stage T3 disease). WC was positively correlated with nephrometry score, even after controlling for age, sex, race, and diabetes status (P = 0.02), whereas BMI and RRF were not (P = 0.13, and P = 0.57, respectively). WC in stage T2/T3 subjects was higher than in subjects with benign masses (P = 0.03). In contrast, subjects with Fuhrman grade 1 and 2 tumors had higher BMI (P<0.01) and WC (P = 0.04) than subjects with grade 3 and 4 tumors.

CONCLUSIONS

Our data suggest that obesity measured by WC, but not BMI or RRF, is associated with increased renal mass complexity. Tumor Fuhrman grade exhibited a different trend, with both high WC and BMI associated with lower-grade tumors. Our findings indicate that WC and BMI are not interchangeable obesity metrics. Further evaluation of RCC-specific outcomes using WC vs. BMI is warranted to better understand the complex relationship between general vs. abdominal obesity and RCC characteristics.

Reproducibility and interobserver agreement of the R.E.N.A.L. nephrometry score: focus on imaging features

OBJECTIVE

To investigate the reproducibility and interobserver agreement for R.E.N.A.L. nephrometry scoring system.

MATERIALS AND METHODS

Two independent radiologists retrospectively analyzed 46 consecutive patients with renal masses, between 2008 and 2012, using the R.E.N.A.L. nephrometry score (RENAL-NS), which is based on the evaluation of five anatomical features of the tumor, as evaluated with computed tomography or magnetic resonance imaging: Radius, Exophytic/endophytic properties, Nearness to the collecting system, Anterior or posterior descriptor, and Location relative to the polar line. Tumor complexity was graded as low, intermediate, or high. The interobserver agreement was calculated for the total score and for the score for each parameter. Surgical excision of the tumors was used as the standard of reference.

RESULTS

The interobserver agreement for each of the RENAL-NS parameters, respectively, a hilar location, and the total score was 98%, 80%, 100%, 89%, 85%, 89%, and 93% of patients, corresponding to kappa values of 0.96, 0.65, 1.00, 0.75, 0.72, 0.78, and 0.88, respectively. The Nearness, Radius, and total score showed the best agreement. For the cases that were discordant in terms of the final score, no major implications in surgical planning were observed.

CONCLUSION

The RENAL-NS is a structured, useful system to assess the anatomical features of renal tumors. It is easily applicable and reproducible, even for less experienced radiologists.

Predictive factors for complete renal tumor ablation using RFA

BACKGROUND

Radiofrequency ablation (RFA) can be used to treat renal masses in patients where surgery is preferably avoided. As tumor size and location can affect ablation results, procedural planning needs to identify these factors to limit treatment to a single session and increase ablation success.

PURPOSE

To identify factors that may affect the primary efficacy of complete renal tumor ablation with radiofrequency after a single session.

MATERIAL AND METHODS

Percutaneous RFA (using an impedance based system) was performed using computed tomography (CT) guidance. Fifty-two renal tumors (in 44 patients) were retrospectively studied (median follow-up, 7 months). Data collection included patient demographics, tumor data (modified Renal Nephrometry Score, histopathological diagnosis), RFA treatment data (electrode placement), and follow-up results (tumor relapse). Data were analyzed through generalized estimating equations.

RESULTS

Primary efficacy rate was 83%. Predictors for complete ablation were optimal electrode placement (P = 0.002, OR = 16.67) and increasing distance to the collecting system (P = 0.02, OR = 1.18). Tumor size was not a predictor for complete ablation (median size, 24 mm; P = 0.069, OR = 0.47), but all tumors ≤2 cm were completely ablated. All papillary tumors and oncocytomas were completely ablated in a single session; the most common incompletely ablated tumor type was clear cell carcinoma (6 of 9).

CONCLUSION

Optimal electrode placement and a long distance from the collecting system are associated with an increased primary efficacy of renal tumor RFA. These variables need to be considered to increase primary ablation success. Further studies are needed to evaluate the effect of RFA on histopathologically different renal tumors.

Trends in the Use of Nephron-Sparing Surgery over 7 Years: An Analysis Using the R.E.N.A.L. Nephrometry Scoring System

OBJECTIVE

To analyze trends in the use of partial nephrectomy, we evaluated which individual factors of renal nephrometry score (RNS) influenced the operative approach bi-annually from 2008 to 2014.

MATERIALS AND METHODS

We performed a retrospective review of renal cell carcinoma treated by surgery in 2008, 2010, 2012, and 2014. The complexity of renal masses was measured using the R.E.N.A.L. nephrometry scoring system with CT or MRI. Group comparison in terms of operation year and surgical type (partial nephrectomy versus radical nephrectomy) was performed. We developed a nomogram to quantitate the likelihood of selecting partial nephrectomy over radical nephrectomy.

RESULTS

A total of 1106 cases (237 in 2008, 225 in 2010, 292 in 2012, and 352 in 2014) were available for the study. Over the study period, the proportion of partial nephrectomies performed increased steadily from 21.5% in 2008 to 66.5% in 2014 (p < 0.05). Furthermore, use of partial nephrectomy increased steadily in all RNS complexity groups (low, moderate, and high) (p < 0.05). In the analysis of individual components of RNS, values of the R and N components increased statistically by year in the partial nephrectomy group (p < 0.05). Average AUC was 0.920.

CONCLUSIONS

The proportion of partial nephrectomies performed sharply increased over the study period. Additionally, over the study period, more partial nephrectomies were performed for renal masses of larger size and closer to the collecting system and main renal vessels. A nomogram developed based on this recent data set provides significant predictive value for surgical decision making.

An Arterial Based Complexity (ABC) Scoring System to Assess the Morbidity Profile of Partial Nephrectomy

BACKGROUND

Tumor characteristics affect surgical complexity and outcomes of partial nephrectomy (PN).

OBJECTIVE

To develop an Arterial Based Complexity (ABC) scoring system to predict morbidity of PN.

DESIGN, SETTING, AND PARTICIPANTS

Four readers independently scored contrast-enhanced computed tomography images of 179 patients who underwent PN.

INTERVENTION

Renal cortical masses were categorized by the order of vessels needed to be transected/dissected during PN. Scores of 1, 2, 3S, or 3H were assigned to tumors requiring transection of interlobular and arcuate arteries, interlobar arteries, segmental arteries, or in close proximity of the renal hilum, respectively during PN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Interobserver variability was assessed with kappa values and percentage of exact matches between each pairwise combination of readers. Linear regression was used to evaluate the association between reference scores and ischemia time, estimated blood loss, and estimated glomerular filtration rates at 6 wk and 6 mo after surgery adjusted for baseline estimated glomerular filtration rate. Fisher's exact test was used to test for differences in risk of urinary fistula formation by reference category assignment.

RESULTS AND LIMITATIONS

Pairwise comparisons of readers' score assignments were significantly correlated (all p<0.0001); average kappa = 0.545 across all reader pairs. The average proportion of exact matches was 69%. Linear regression between the complexity score system and surgical outcomes showed significant associations between reference category assignments and ischemia time (p<0.0001) and estimated blood loss (p=0.049). Fisher's exact test showed a significant difference in risk of urinary fistula formation with higher reference category assignments (p=0.028). Limitations include use of a single institutional cohort to evaluate our system.

CONCLUSIONS

The ABC scoring system for PN is intuitive, easy to use, and demonstrated good correlation with perioperative morbidity.

PATIENT SUMMARY

The ABC scoring system is a novel anatomy-reproducible tool developed to help patients and doctors understand the complexity of renal masses and predict the outcomes of kidney surgery.

Are urologists and radiologists equally effective in determining the RENAL Nephrometry score?

BACKGROUND

The RENAL nephrometry score (RNS) allows description of the anatomy and the complexity of renal masses. This study aimed to investigate the interobserver reproducibility of the RNS between a radiologist and a urologist.

METHODS

The computed tomography (CT) scans of patients undergoing partial nephrectomy in the authors' department between June 2010 and June 2013 were analyzed for determination of the RNS by a urologist and a radiologist blinded to the medical records. Cohen's kappa coefficient was used for interobserver reproducibility assessment. Correlations with per- and postoperative complication rates and renal function were assessed.

RESULTS

The study included 52 consecutive patients with a mean age of 55 years. The average score was 7.4 ± 1.7 for the urologist and 7.3 ± 1.5 for the radiologist. The Cohen's kappa was 0.81 for R, 0.47 for E, 0.63 for N, 0.28 for A, and 0.21 for L. The Pearson's coefficient for the total RNS was 0.70. The operative time and the occurrence of major complications were significantly correlated with the complexity assessed by the score of both observers. In the univariate analysis, the RNS, the American Society of Anesthesiologists score, and the patient's age were significantly associated with major complication rates. In the multivariate analysis, the RNS remained significantly associated with major complications. No significant difference in postoperative renal function according to complexity group was found by either the urologist or the radiologist.

CONCLUSIONS

The reproducibility of the RNS between the radiologist and the urologist was not very good, especially for some items referring to the location of the tumor, although the major complication rates were significantly associated with the RNS for both observers.

Nephrometry scores: interobserver reproducibility and perioperative factors prediction

OBJECTIVES

To validate the relation of the nephrometry scores in a series of patients who underwent partial nephrectomy with perioperative parameters and the urologist-radiologist reproducibility.

MATERIAL AND METHODS

A retrospective study of open and laparoscopic partial nephrectomy patients performed between 2005 and 2012 registered in prospective filled out database. An urologist and a radiologist calculated the R.E.N.A.L., PADUA and C-index for 86 patients. We carried out a comparative study of the results using the Spearman and Pearson correlation indexes.

RESULTS

Distribution according to the complexity of the tumors with the RENAL calculation was: 42 (49%) low, 35 (41%) moderated and 9 (11%) high complexity. According to PADUA: 35 (41%) low complexity, 32 (37%) intermediate and 19 (22%) high. No statistically significant correlation was found for the appearance of operative complications and the pathology results in case of RENAL and PADUA. A correlation was found in the case of PADUA in relation to the warm ischemia time. Positive correlation according to Spearman's index was found in RENAL, PADUA and C-index between urologist and radiologist evaluations.

CONCLUSIONS

Nephrometry scores can be a useful tool to plan the surgical technique or approach. However, it is not clear if they are really predictors of surgical or pathologic parameters. The correlation between the urologist and radiologist seems to be sufficient to recommend their use by both specialties.

Interobserver variability of R.E.N.A.L., PADUA, and centrality index nephrometry score systems

PURPOSE

To assess interobserver variability of R.E.N.A.L., preoperative aspects and dimensions used for an anatomical classification system (PADUA), and centrality index (C-Index) systems among observers with varying degrees of clinical experience and each system's subscale correlation with surgical outcome metrics.

METHODS

Computed tomography images of 90 patients who underwent open, laparoscopic, or robot-assisted laparoscopic partial nephrectomy were scored by one radiology fellow, two urology fellows, one radiology resident, and one secondary school student. Agreement among readers was determined calculating intraclass correlation coefficients. Associations between radiology fellow scores (reference standard as reader with greatest clinical experience), ischemia time, and percent change in postoperative estimated glomerular filtration rate (eGFR) were evaluated using Spearman's correlation.

RESULTS

Agreement using C-Index method (ICC = 0.773) was higher than with PADUA (ICC = 0.677) or R.E.N.A.L (ICC = 0.660). Agreement between reference and secondary school student was lower than with other physicians, although the differences were not statistically significant. The reference's scores were significantly (p < 0.05) associated with ischemia time on all three scoring systems and with percent change in eGFR at 6 weeks using C-Index (p = 0.016). Tumor size, nearness to sinus, and location relative to polar lines (R.E.N.A.L.) and tumor size, renal sinus involvement, and collecting system involvement (PADUA) correlated with ischemia time (all p ≤ 0.001). No R.E.N.A.L. or PADUA subscales significantly correlated with percent change in postoperative eGFR.

CONCLUSIONS

Clinical experience reduces interobserver variability of existing nephrometry systems though not significantly and less so when using directly measureable anatomic variables. Consistently, only measures of tumor size and distance to intrarenal structures were useful in predicting clinically relevant outcomes.

The initial experience with RENAL Nephrometry in children, adolescents, and young adults with renal tumors

BACKGROUND

No standardized manner exits to objectively compare renal tumor complexity in children and adolescents. However, the RENAL Nephrometry scoring system has been recently developed in adults and shown to predict tumor complexity and correlate with clinical outcomes. Thus, the study objective was to evaluate RENAL Nephrometry tumor score in a population of children, adolescents, and young adults and correlate it with tumor features and pathology.

METHODS

Patients at the study institution who underwent attempted renal tumor resection from 2002 to 2012, and had pre-operative imaging available for scoring were retrospectively reviewed. A Nephrometry score for each affected kidney was calculated separately by two blinded reviewers and the final score was based on consensus review. Tumor characteristics and oncologic outcomes were compared between the low-, moderate-, and high-complexity masses.

RESULTS

Sixty-five patients and 67 kidneys met study criteria. This included: 5 (7.5%) low-complexity, 11 (16.4%) moderate-complexity, and 51 (76.1%) high-complexity lesions. In comparing the clinical and pathologic features between groups, it was observed that less complex masses were observed in older patients, were more commonly managed with nephron-sparing surgery, and more often represented renal cell carcinoma (RCC) and other non-Wilms tumor pathology. No statistically significant correlation was observed between tumor complexity score and blood loss, operative time, transfusion requirement, positive margins or tumor rupture.

CONCLUSION

In general, renal lesions in this population are highly complex. In its current form, RENAL Nephrometry appears most useful in evaluating tumor complexity in RCC and masses in older children and adolescents.

High R.E.N.A.L. Nephrometry scores are associated with pathologic upstaging of clinical T1 renal-cell carcinomas in radical nephrectomy specimens: implications for nephron-sparing surgery

BACKGROUND AND PURPOSE

The R.E.N.A.L. Nephrometry Score (RNS) was developed to standardize the reporting of anatomic information of a renal mass. This study aimed to identify the association of preoperative clinical and tumor features assessed by the RNS with pathologic upstaging of clinical T1 renal-cell carcinomas (RCCs) in complete en bloc radical nephrectomy (RN) specimens.

PATIENTS AND METHODS

A review was performed for 65 consecutive patients (2005-2013) who underwent RNs for a unilateral clinical T1N0M0 RCC. The RNS was measured in all patients based on preoperative CT scans. Pathologic review was performed to identify patients with final pathologic upstaging. Associations were assessed with the Fisher exact test, Student t test, and Wilcoxon rank sum test.

RESULTS

Of the 65 patients (41 male, mean age 59 years), 4 (6%) patients were upstaged to pT2 and 16 (25%) were upstaged to pT3a and above in the final histologic evaluation. Upstaged patients were not significantly different from those without in terms of age, sex, race, surgical approach, side of surgery, Fuhrman grade, and histologic cell type. Independent tumor features associated with pathologic upstaging were (R) tumor diameter (P=0.021), and (L) central location within polar lines (P=0.010). Tumors that were upstaged had a higher median total RNS than those without (10 vs 9, P=0.010). Complex tumors, with RNS≥10, were associated with significantly increased risk of upstaging compared with low and intermediate complexity categories (RNS<10) (relative risk=2.56, 95% confidence interval 1.22-5.37, P=0.014).

CONCLUSIONS

A higher RNS was associated with an increased risk of upstaging in clinical T1 cancers, predominantly from perinephric or sinus fat invasion in RN pathologic specimens. This may have implications on the selection of surgical option for the clinical T1 renal mass.

R.E.N.A.L. Nephrometry scoring: how well correlated are urologist, radiologist, and collaborator scores?

PURPOSE

R.E.N.A.L. Nephrometry Score (NS) is an imaging-based (CT/MRI) scoring system commonly used by urologists to standardize the reporting of renal masses by enabling quantification of anatomical characteristics. We sought to examine the inter-rater correlation of NS between urologists, radiologists, and tumor-board collaborators.

METHODS

We identified adult patients undergoing partial or radical nephrectomy over 10 years (n=2450). Patients with autosomal dominant polycystic kidney disease (ADPKD), metastatic disease, masses >10 cm, and studies in which the study urologists or radiologists partook in patient care were excluded. Preoperative imaging was evaluated and patients with multiphasic CT available were included. Scans were provided to the reviewers to evaluate with a R.E.N.A.L. nephrometry questionnaire. Results were analyzed using kappa correlation coefficients.

RESULTS

One hundred twenty patients met inclusion criteria with mean age of 59.5 years. The majority of cases were partial nephrectomies (72%). Eighty-five percent of the tumors were malignant, with 26% having high-grade histology. The mean (standard deviation) overall NS was 6.8 (1.9) with fair correlation among reviewers (κ=0.222). Collaborators had the highest inter-rater correlation, ranging from 0.41 to 0.84 for NS component scores, compared with 0.42-0.85 for radiologists and 0.36-0.86 for urologists. "R" scores were best correlated (κ>0.8). NS correlation ranged between 0.16 and 0.31 for the groups while the NS complexity category correlation ranged between 0.50 and 0.61.

CONCLUSIONS

Despite being naive to NS, inter-radiologist scoring patterns were better correlated than inter-urologist. The urologist and radiologist collaborating in tumor board showed the highest agreement, suggesting that a multidisciplinary approach in the characterization of renal masses may provide benefit to patient management.

Factors Influencing the Operative Approach to Renal Tumors: Analyses According to RENAL Nephrometry Scores

Purpose

To evaluate the relationship between RENAL nephrometry score (RNS) and operative approach for renal masses.

Materials and Methods

This study included 206 consecutive patients who underwent renal tumor surgery between January 2008 and October 2012. We divided the patients into four groups by surgical approach: open radical nephrectomy (ORN, 53 patients), laparoscopic radical nephrectomy (LRN, 83 patients), open partial nephrectomy (OPN, 31 patients), and laparoscopic partial nephrectomy (LPN, 39 patients). We retrospectively assessed the RNS for each surgery group and evaluated the relationship between this score and operative approach.

Results

The mean RNSs of the ORN, LRN, OPN, and LPN groups were 9.75, 8.35, 6.72, and 5.76, respectively. When the RNS was analyzed according to nephron-sparing, the mean RNSs of the RN groups (ORN and LRN) and the PN groups (OPN and LPN) were significantly different (8.89 and 6.09, respectively; p<0.001). All the individual components of the RNS were significantly different between RN and PN. In the RN groups, the criteria for open versus laparoscopic surgery were based on tumor size ('R' score=2.43 for open, 1.54 for laparoscopic, p<0.001) and tumor location relative to the polar line ('L' score=2.55 for open, 2.09 for laparoscopic, p=0.006). In the PN groups, the criteria for open or laparoscopic surgery were based only on exophytic/endophytic property ('E' score=1.87 for open, 1.41 for laparoscopic, p=0.046).

Conclusions

The RNS was significantly different in all surgery groups. The decision to take a laparoscopic approach was primarily influenced by the R and L scores for RN and by the E score for PN.

Clinical analysis of the PADUA and the RENAL scoring systems for renal neoplasms: a retrospective study of 245 patients undergoing laparoscopic partial nephrectomy

OBJECTIVE

To investigate the clinical significance of preoperative aspects and dimensions used for anatomic (PADUA) and radius exophytic/endophytic nearness anterior/posterior location (RENAL) scoring systems for renal neoplasms in patients undergoing laparoscopic partial nephrectomy.

METHODS

A retrospective analysis was carried out on clinical data of 245 Chinese patients with renal neoplasms undergoing laparoscopic partial nephrectomy from June 2008 to June 2012. The perioperative complications and variables, as well as PADUA and RENAL score, were compared.

RESULTS

The PADUA and RENAL scoring systems were significantly associated with percent change in estimated glomerular filtration rate (P = 0.032 and P = 0.026 respectively), whereas the RENAL scoring system was also significantly associated with warm ischemia time (P = 0.032). On multivariate analysis, both scores were able to predict percent change in estimated glomerular filtration rate (PADUA, P = 0.011; RENAL, P = 0.028). There were no significant associations between the two scoring systems assessed and the occurrence of complications or tumor stage. The correlation between PADUA classification and RENAL nephrometry score was significant (P < 0.0001). Fleiss' generalized kappa was 0.69-0.89 for the various components of the PADUA score and 0.67-0.89 for the RENAL nephrometry components.

CONCLUSIONS

The PADUA classification and RENAL nephrometry score are comprehensive assessment tools for delineating renal tumor anatomy. The reproducibility of the PADUA and RENAL scores is substantial, but further research is required to evaluate its performance in more accurately predicting operative and patient-related outcomes.