The Application of R.E.N.A.L. Nephrometry Scoring System in Predicting the Complications After Laparoscopic Renal Radiofrequency Ablation

External validation of the ability of the mRENAL nephrometry score to identify patients at risk for major adverse events or local tumor recurrence after percutaneous renal cryoablation

PURPOSE

The purpose of this study was to evaluate the ability of the mRENAL score to identify patients at risk of either major adverse events (AEs) and/or local tumor recurrence (LR) after percutaneous cryoablation (PCA) in an external patient population.

METHODS

Patient demographic data were recorded. The RENAL and mRENAL nephrometry scores were calculated. Clinical outcomes such as AEs, LR, cancer-specific survival (CSS), and overall survival (OS) were collected. AEs were classified according to SIR criteria. Continuous variables and categorical variables were analyzed using the Wilcoxon rank sum test and chi-square test, respectively. Logistic regression analysis was performed to identify variables associated with major AEs or LR.

RESULTS

The study included 207 patients (Males: n = 117 (56.5%)) with a mean age of 65.8 (± 11.2) years (range:27-90). Overall, the mean tumor diameter, RENAL score, and mean mRENAL score were 30.1 mm (± 11.4), 6.3 (± 1.7), and 6.8 (± 1.9), respectively. 14 patients (6.8%) and 13 patients (6.3%) experienced a major AE or LR after PCA, respectively. CSS and OS were 98.6% and 90.3%, respectively. For patients with major AEs after PCA, the mean tumor diameter (p < 0.0001), mean RENAL score (p = 0.03), and mean mRENAL score (p = 0.009) were all higher than those for patients without a major AE. Multi-variate regression analysis showed that only mean tumor diameter (p = 0.005) was predictive of a major AE. There were no statistically significant differences between patients with LR and patients without LR after PCA with regards to tumor size (p = 0.07), mean RENAL score (p = 0.32), or mean mRENAL score (p = 0.07). Multi-variate regression analysis showed that only mean tumor diameter (p = 0.01) was predictive of LR.

CONCLUSION

The mRENAL score did not accurately identify patients at risk for either major AEs or LR. Maximum tumor diameter alone was predictive of both major AEs and LR, and should be the primary focus during patient selection.

Usefulness of renal nephrometry scoring systems in the prediction of complications associated to percutaneous image-guided treatment for small renal masses

INTRODUCTION

Due to their increasing prevalence and complex management, renal tumors are challenging for health professionals. The study aims to evaluate the usefulness of R.E.N.A.L. and PADUA nephrometry scores in the prediction of complications after percutaneous cryoablation.

MATERIAL AND METHODS

The study prospectively analyzed 90 patients with 101 stage T1a renal cell carcinoma (RCC) tumors treated with cryoablation.

RESULTS

Ninety patients with 101 small renal tumors who received cryoablative therapy were investigated. The mean age of the patients was 68 years and 74.4% were male. Most tumors were smaller than 4 cm (89.1%) and the mean PADUA and R.E.N.A.L. scores were 8.65 and 7.35, respectively. Complications were observed in 12 cases. PADUA and R.E.N.A.L. scores demonstrated moderate predictive power (AUC = 0.58 and AUC = 0.63, respectively) for post-cryoablation complications.

CONCLUSIONS

Percutaneous cryoablation is a safe and effective treatment for small renal tumors. The R.E.N.A.L. and PADUA renal nephrometry scores have moderate predictive power for complications associated with percutaneous cryoablation of renal tumors.

Utility of the RENAL Nephrometry Scoring System in Predicting Adverse Events and Outcomes of Percutaneous Microwave Ablation of Renal Tumors

PURPOSE

To assess the utility of the radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines (RENAL) nephrometry scoring system at predicting adverse events and outcomes in percutaneous microwave ablation (MWA) of renal tumors.

MATERIALS AND METHODS

A retrospective review of 116 patients who underwent MWA from 2004 to 2018 at 2 large university hospitals was conducted. Patient demographics and tumor characteristics were collected. The RENAL nephrometry scores were calculated, and procedure-related adverse events were stratified into minor and major (the Society of Interventional Radiology classification of class C or higher). Technical and oncologic outcomes were based on follow-up magnetic resonance imaging and computed tomography scans after ablation.

RESULTS

The mean RENAL score was 6.6 (range, 4-11), and the mean tumor size was 24 mm. Follow-up ranged between 16 and 161 weeks (median, 50 weeks; mean, 65 weeks). Oncologic control was achieved in 96% (n = 111) of patients. The major and minor adverse event rates were 8.6% (n = 10) and 17% (n = 19), respectively. The mean RENAL score for patients with recurrent and/or residual tumor (8.2 ± 2.7) was higher than that for patients without disease recurrence (6.5 ± 3.5, P = .05). However, in a multivariate analysis, the RENAL score was not found to be an independent predictor of oncologic outcomes (odds ratio, 1.548; P = .092).

CONCLUSIONS

The RENAL nephrometry score has minimal utility for predicting outcomes and adverse events in MWA of renal tumors. The inconsistent nature of RENAL nephrometry scoring in percutaneous ablation procedures underscores the need for an ablation-specific risk stratification system.

The effectiveness of RENAL nephrometry score in ablated renal tumors via radiofrequency ablation or cryoablation

Background/aim

This study aimed to evaluate the clinical efficacy of radiofrequency ablation (RFA) and cryotherapy and to scrutinize the therapeutic success of the RENAL (radius, exophytic/endophytic, nearness to collecting system, anterior/posterior, and location) nephrometry score in terms of possible complications and the predictive status of oncological results.

Materials and methods

Forty-five patients with biopsy-proven renal cell carcinomas (32 males, 13 females) treated with RFA and cryotherapy were included. Patients were 22–90 years old (average: 59.2 years). Statistical analyses were performed using SPSS for Windows.

Results

A total of 79 lesions with dimensions varying between 0.9 and 4.5 cm (average: 2.2 cm) were ablated. Complete ablation was achieved for 72 (91.1%) lesions. Six repeat RFA sessions were applied for 4 (5%) lesions with residue/recurrence. The average RENAL nephrometry scores of lesions that underwent complete ablation and those that developed residue/recurrence were 6.3 and 7.7, respectively. The average recurrence-free survival time was 34.8 months (range: 3–55 months), while it was 44.6 months (range: 6–55 months) for cryotherapy and 28.6 months (range: 3–50 months) for RFA.

Conclusion

Ablative therapies are minimally invasive and effective methods for treating small renal tumors. RENAL nephrometry scoring is a valuable system for standardizing renal tumors and evaluating the success of ablative therapies, possible complications, and oncological results.

The effect of tumor size and location on efficacy and safety of US- and CT- guided percutaneous microwave ablation in renal cell carcinomas

PURPOSE

To evaluate the effect of size and central location of the tumor on safety and efficacy of percutaneous CEUS- and CT-guided MWA in biopsy-proven renal cell carcinomas (RCCs).

MATERIALS AND METHODS

In this IRB-approved retrospective study, 69 biopsy-proven renal tumors in 56 patients, who underwent MWA in our institution from January 2013 to March 2017, were evaluated. Data collection included demographics, tumor characteristics, procedural protocols, and follow-up visits within 6 months post procedure. Primary outcomes were assessed by technical success (TS), local tumor progression (LTP), and complications. The Kaplan-Meier analysis was used for survival rate.

RESULTS

Overall technical success was achieved for all 69 lesions (92.8% primary TS, 100% overall). Median nephrometry score was 8 (4-11) and median tumor size was 2.5 cm (0.8-7). Five lesions which required second ablation had significantly higher median tumor size 4 cm (P = 0.039) with the same nephrometry score. Renal function remained stable with no significant change in eGFR before or after ablation. The LTP rate was 5.8%. The most recurrent tumors were clear cell (50%) followed by papillary tumors (25%). The complication rate was 5.8% with minor complications (hematoma and pain) and no major issues. There was no significant association between nephrometry score and technical success, recurrence, or complication rates. Overall and tumor-specific survival rates were 96.7% and 100% at 11.9 months.

CONCLUSIONS

Image-guided MWA appears to be a safe and effective treatment regardless of nephrometry score and tumor location with high technical success, low recurrence, and complication rates.

Perioperative outcomes of zero ischemia radiofrequency ablation-assisted tumor enucleation for renal cell carcinoma: results of 182 patients

BACKGROUND

To evaluate the perioperative outcomes of zero ischemia radiofrequency ablation-assisted tumor enucleation.

METHODS

Patients undergoing zero ischemia radiofrequency ablation-assisted tumor enucleation were retrospectively identified from July 2008 to March 2013. The tumor was enucleated after RFA treatment. R.E.N.A.L., PADUA and centrality index (C-index) score systems were used to assess each tumor case. We analyzed the correlation of perioperative outcomes with these scores. Postoperative complications were graded with Clavien-Dindo system. Multivariate logistic regression analyses were used to assess risk of complications.

RESULTS

Among 182 patients assessed, median tumor size, estimated blood loss, hospital stay and operative time were 3.2 cm (IQR 2.8-3.4), 80 ml (IQR 50-120), 7 days (IQR 6-8) and 100 min (IQR 90-120), respectively. All three scoring systems were strongly correlated with estimated blood loss, hospital stay and operative time. We found 3 (1.6%) intraoperative and 23 (12.6%, 13 [7.1%] Grade 1 and 10 [5.5%] Grade 2 & 3a) postoperative complications. The median follow-up was 55.5 months (IQR 45-70). Additionally, the complexities of R.E.N.A.L., PADUA and C-index scores were significantly correlated with complication grades (P < 0.001; P < 0.001; P < 0.001; respectively). As the representative, R.E.N.A.L. score was an independent predictive factor for postoperative complications and patients with a high complexity had an over 24-fold higher risk compared to those with a low complexity (OR 24.360, 95% CI 4.412-134.493, P < 0.001).

CONCLUSIONS

Zero ischemia radiofrequency ablation-assisted tumor enucleation is considered an effective nephron-sparing treatment. Scoring systems could be useful for predicting perioperative outcomes of radiofrequency ablation-assisted tumor enucleation.

Role of R.E.N.A.L. Nephrometry Score in Laparoscopic Partial Nephrectomy

Background:

Preoperative anatomical scoring system is conducive to comparison between treatment options and evaluation of postoperative outcomes in patients with small renal tumors. This study aimed to evaluate the clinical application efficacy of the R.E.N.A.L. nephrometry score (RNS) in predicting perioperative outcomes in patients with renal tumor who underwent laparoscopic partial nephrectomy (LPN).

Methods:

The clinical data of 139 patients with renal tumors who underwent LPN between 2009 and 2015 were collected and analyzed. Patients were divided into three groups according to their RNS (low, moderate, and high). Clinical characteristics including perioperative variables, complications, and RNS were compared to evaluate the differences between the three groups. Multivariable logistic regression analysis was used to analyze the risk factors of postoperative complications.

Results:

According to the RNS, there were 74, 50, and 15 patients in the low, moderate, and high RNS groups, respectively. There were significant differences in estimated blood loss (EBL; χ² = 7.285, P = 0.026), warm ischemia time (WIT; χ² = 13.718, P = 0.001), operation time (OT; χ² = 6.882, P = 0.032), perioperative creatinine clearance change (PCCC; χ² = 6.206, P = 0.045), and number of patients with complications (NPC; P = 0.002) among the three groups. The values for EBL, WIT, OT, PCCC, and NPC for patients in the high RNS group were higher than those for patients in the low RNS group. After adjustment for OT, WIT, and EBL, RNS was statistically significantly associated with the risk of postoperative complications in a multivariable logistic regression model (odds ratio = 1.541, 95% confidence interval: 1.059–2.242, P = 0.024).

Conclusions:

The RNS is a valuable tool for evaluating the complexity of renal tumor anatomy. It can aid surgeons in preoperative decision-making concerning management therapy. Future multicenter, large sample size studies are warranted for evaluating its predicting performance of perioperative outcomes.

Comparison of radiofrequency ablation and partial nephrectomy for tumor in a solitary kidney

Background

To estimate oncologic and functional outcomes for radiofrequency ablation (RFA) versus partial nephrectomy (PN) for tumors in a solitary kidney.

Methods

Nineteen patients with sporadic renal cell carcinoma in a solitary kidney were treated with RFA, and 21 patients were treated with PN between November 2008 and September 2015. Basic demographic information including age, gender, operative and pathological data, complications, renal function, oncological outcomes, was obtained for each patient. Statistical analysis was done to test for the correlation of clinical and pathological features, renal function outcomes, as well as oncological outcomes of RFA and PN. All statistical tests were 2-sided, and p-value < 0.05 was considered significant. Statistical analyses were performed using SPSS 19.0.

Results

No significant differences were indicated between the RFA and PN with respect to mean patient age, tumor size, as well as intraoperative or postoperative complications. The mean length of hospitalization (P = 0.019) and mean operative time (P = 0.036) was significantly shorter in RFA, with the median estimated blood loss being greater in PN (P = 0.001). The mean serum creatinine level 24 h following operation were significantly higher than preoperative creatinine in PN (P = 0.009), but did not reach statistical significance in RFA. Local recurrence were detected in only 1 patient (5%) in PN and 3 patients (18.75%) in RFA (P = 0.4). One patient developed pulmonary metastasis and one exhibited tumor persistence in RFA, none were present in PN.

Conclusions

Radiofrequency Ablation and Partial Nephrectomy for Tumors in a Solitary Kidney were all safe and effective, with each method having distinct advantages. It is the decision of the patient and urologist to pick the best approach.

Microwave ablation of malignant renal tumours: intermediate-term results and usefulness of RENAL and mRENAL scores for predicting outcomes and complications

The aim of this study was to evaluate intermediate-term results after microwave ablation (MWA) of renal tumours and determine the association of RENAL and modified RENAL (mRENAL) scores with oncological outcomes and complications. In May 2008-September 2014, 58 patients affected by early-stage RCC (renal cell carcinoma; T1a or T1b) were judged unsuitable for surgery and treated with percutaneous MWA. Follow-up was performed with contrast-enhanced computed tomography at 1, 3, 6, 12 and 24 months after the procedure. Technical success (TS), primary technical effectiveness (PTE), secondary technical effectiveness (STE), the local tumour progression rate (LTPR), the cancer-specific survival rate (CSSR), disease-free survival (DFS), overall survival (OS) and safety were recorded. All lesions were evaluated using RENAL and mRENAL scores, and complications were assessed with RENAL scores. The TS rate was 100%, PTE was 93%, STE was 100%, LTPR was 15.7% at 1 year, CSSR was 96.5%, DFS was 87.9% at 5 years, and OS was 80.6%. Mean follow-up was 25.7 months (range 3-72). The mean ± standard deviation (SD) RENAL and mRENAL scores of all treated tumours were 6.7 ± 2.05 (range 4-11) and 7 ± 2.3 (range 4-12), respectively. Major complications occurred in two (2/58) and minor complications in three patients (3/58). Overall complications correlated significantly with RENAL scores; in particular, E and L represent negative predictors for safety and effectiveness. MWA is a valuable alternative for treating RCCs. The correlation with outcomes and complications of RENAL and mRENAL scores could help to customise MWA indications in RCC patients.

Renal Tumor Anatomic Complexity: Clinical Implications for Urologists

Anatomic tumor complexity can be objectively measured and reported using nephrometry. Various scoring systems have been developed in an attempt to correlate tumor complexity with intraoperative and postoperative outcomes. Nephrometry may also predict tumor biology in a noninvasive, reproducible manner. Other scoring systems can help predict surgical complexity and the likelihood of complications, independent of tumor characteristics. The accumulated data in this new field provide provocative evidence that objectifying anatomic complexity can consolidate reporting mechanisms and improve metrics of comparisons. Further prospective validation is needed to understand the full descriptive and predictive ability of the various nephrometry scores.

Neutrophil-to-lymphocyte ratio as an independent predictor for survival in patients with localized clear cell renal cell carcinoma after radiofrequency ablation: a propensity score matching analysis

OBJECTIVE

To investigate the role of neutrophil-to-lymphocyte ratio as a prognostic indicator in patients with localized clear cell renal cell carcinoma treated with radiofrequency ablation.

PATIENTS AND METHODS

We retrospectively analyzed data from patients with renal cell carcinoma who underwent radiofrequency ablation from 2006 to 2013. The Kaplan-Meier method was used to generate the survival curves according to different categories of neutrophil-to-lymphocyte ratio. Relationships between preoperative neutrophil-to-lymphocyte ratio or the change of neutrophil-to-lymphocyte ratio and survival were evaluated with multivariable Cox proportional hazards regression analysis. A propensity score matching analysis was carried out to avoid confounding bias.

RESULTS

A total of 185 patients were included in present study. When stratified by preoperative neutrophil-to-lymphocyte ratio cutoff value of 2.79, 5-year recurrence-free survival, 5-year disease-free survival, and 5-year overall survival rates of neutrophil-to-lymphocyte ratio <2.79 versus ≥2.79 were 100, 98.5, and 99.2% versus 80.5, 72.6, and 90.6%, respectively (P < 0.001, P < 0.001, P = 0.003). In terms of propensity score matching analysis, 5-year recurrence-free survival, 5-year disease-free survival, and 5-year overall survival rates of neutrophil-to-lymphocyte ratio <2.79 versus ≥2.79 were 100, 97.9, and 100% versus 82.3, 73.4, and 89.4%, respectively (P = 0.003, P = 0.001, P = 0.022). When combining preoperative neutrophil-to-lymphocyte ratio with the change of neutrophil-to-lymphocyte ratio, patients with both preoperative neutrophil-to-lymphocyte ratio ≥2.79 and the change of neutrophil-to-lymphocyte ratio ≥0.40 had the worst disease-free survival. Results of multivariable analysis showed that preoperative neutrophil-to-lymphocyte ratio and the change of neutrophil-to-lymphocyte ratio correlated with cancer relapse remarkably.

CONCLUSIONS

High preoperative neutrophil-to-lymphocyte ratio and elevated postoperative neutrophil-to-lymphocyte ratio are associated with significant increase in risk of local recurrence as well as distant metastasis. The combination of neutrophil-to-lymphocyte ratio with the other prognostic indicators can be applied in the evaluation of relapse risk in patients with clear cell renal cell carcinoma after radiofrequency ablation.

Introduction to small renal tumours and prognostic indicators

Over the past years, the widespread use of radiological imaging for evaluating abdominal symptoms unrelated to kidney cancer has been linked to a significant increase in the percentage of renal tumours incidentally detected at an asymptomatic stage. The definition of 'small' renal tumours has changed over the years. Presently, according to dimensional criteria, surgical indications and prognostic impact, small renal tumours are defined as masses ≤4 cm in size. Classical preoperative variables that influence the decision-making process in the management of T1a renal tumours can be classified as patient-related and tumour-related factors. Age is an independent predictor of cancer-specific survival (CSS), with older patients exhibiting significantly worse survival. An accurate classification of the anatomical and topographical characteristics of small renal masses based on available nephrometry systems is necessary for standard preoperative evaluation of patients eligible for partial nephrectomy (PN). Renal tumour biopsies (RTBs) can be indicated in patients eligible for active surveillance or ablative treatments, those with other primary tumours, those with prior renal lesions and/or those with multiple synchronous tumours, showing a median diagnostic rate of 92%. Small renal tumours typically have a good prognosis. Patient age, mode of presentation, nuclear grading, coagulative necrosis and histologic subtype can influence the prognosis of this subgroup of RCC.

The Comparison of R.E.N.A.L., PADUA and Centrality Index Score in Predicting Perioperative Outcomes and Complications after Laparoscopic Radio Frequency Ablation of Renal Tumors

PURPOSE

We assessed the association between the R.E.N.A.L., PADUA and centrality index scores and perioperative outcomes, and determined the efficacy of each scoring system over the simple parameter of tumor size.

MATERIALS AND METHODS

We conducted a retrospective review of the records of patients who underwent laparoscopic radio frequency ablation of renal tumors from February 2006 to April 2014 at our institution. Tumors were categorized using the R.E.N.A.L., PADUA and centrality index score, which were determined by analyzing preoperative imaging. The relationships between each variable and change in glomerular filtration rate, estimated blood loss, operative time and postoperative complications were examined.

RESULTS

Laparoscopic radio frequency ablation was performed in 215 selected patients with preoperative imaging available. The interclass correlations coefficient of the 3 observers was 0.87, 0.84 and 0.82 for the C-Index, the R.E.N.A.L. and the PADUA scoring system, respectively. R.E.N.A.L. score, PADUA score and PADUA complexity were significantly associated with postoperative complications (p=0.040, 0.015 and 0.006, respectively). However, major complications were only associated with high PADUA complexity (chi-square 23.851, p <0.05). Each scoring system had a significant association with operative time and estimated blood loss (p <0.05), except that the C-index score had no relationship with estimated blood loss (p=0.083). The accuracy of each scoring system in predicting perioperative outcomes and postoperative complications was superior to that of tumor size.

CONCLUSIONS

Each scoring system has an advantage over tumor size in describing tumor complexity and may help with surgical decision making. Further studies are required to validate their efficacy in evaluating the intraoperative and postoperative results after renal laparoscopic radio frequency ablation.

Radio frequency ablation versus partial nephrectomy for clinical T1b renal cell carcinoma: long-term clinical and oncologic outcomes

PURPOSE

We compared outcomes in patients treated with radio frequency ablation or partial nephrectomy for clinical cT1b renal cell carcinoma.

MATERIALS AND METHODS

We retrospectively reviewed the records of all patients who underwent radio frequency ablation or nephrectomy between February 2006 and December 2010. Radiographic followup with contrast imaging was performed 7 days, 3 and 6 months, and every 6 months thereafter after radio frequency ablation sequentially. The followup protocol for partial nephrectomy was every 6 months in the initial 3 years and annually thereafter. The Kaplan-Meier method was used to generate survival curves, which were compared with the log rank test. Multivariable regression analysis was done to determine predictors of survival.

RESULTS

A total of 56 patients who met selection criteria were included in study. Patients in the radio frequency ablation group had relatively higher mean age and a higher mean ASA® score than those in the partial nephrectomy group. Mean tumor diameter was significantly larger in the partial nephrectomy cohort. For radio frequency ablation vs partial nephrectomy 5-year overall, cancer specific and disease-free survival was 85.5% (95% CI 72.2-98.8) vs 96.6% (95% CI 95.9-97.3), 92.6% (95% CI 82.4-98.1) vs 96.6% (95% CI 95.9-97.3) and 81.0% (95% CI 66.2-95.8) vs 89.7% (95% CI 78.5-97.9), respectively. The percent decrease in the glomerular filtration rate was significantly lower in the radio frequency ablation group at early and last followup.

CONCLUSIONS

In appropriately selected patients with stage cT1b renal cell carcinoma radio frequency ablation is an effective treatment option that provides 5-year overall, cancer specific and disease-free survival comparable to that of partial nephrectomy as well as better renal function preservation than partial nephrectomy.