R.E.N.A.L. (Radius, Exophytic/Endophytic, Nearness to Collecting System or Sinus, Anterior/Posterior, and Location Relative to Polar Lines) Nephrometry Score Predicts Early Tumor Recurrence and Complications after Percutaneous Ablative Therapies for Renal Cell Carcinoma: A 5-Year Experience

Percutaneous Microwave Ablation versus Cryoablation for Small Renal Masses (≤4 cm): 12-Year Experience at a Single Center

PURPOSE

To determine whether microwave ablation (MWA) has equivalent outcomes to those of cryoablation (CA) in terms of technical success, adverse events, local tumor recurrence, and survival in adult patients with solid enhancing renal masses ≤4 cm.

MATERIALS AND METHODS

A retrospective review was performed of 279 small renal masses (≤4 cm) in 257 patients (median age, 71 years; range, 40-92 years) treated with either CA (n = 191) or MWA (n = 88) between January 2008 and December 2020 at a single high-volume institution. Evaluations of adverse events, treatment effectiveness, and therapeutic outcomes were conducted for both MWA and CA. Disease-free, metastatic-free, and cancer-specific survival rates were tabulated. The estimated glomerular filtration rate was employed to examine treatment-related alterations in renal function.

RESULTS

No difference in patient age (P = .99) or sex (P = .06) was observed between the MWA and CA groups. Cryoablated lesions were larger (P < .01) and of greater complexity (P = .03). The technical success rate for MWA was 100%, whereas 1 of 191 cryoablated lesions required retreatment for residual tumor. There was no impact on renal function after CA (P = .76) or MWA (P = .49). Secondary analysis using propensity score matching demonstrated no significant differences in local recurrence rates (P = .39), adverse event rates (P = .20), cancer-free survival (P = .76), or overall survival (P = .19) when comparing matched cohorts of patients who underwent MWA and CA.

CONCLUSIONS

High technical success and local disease control were achieved for both MWA and CA. Cancer-specific survival was equivalent. Higher adverse event rates after CA may reflect the tendency to treat larger, more complex lesions with CA.

Nephrometry scores to predict oncological outcomes following partial nephrectomy (UroCCR Study 70)

PURPOSE

Partial nephrectomy (PN) for large or complex renal tumors can be difficult and associated with a higher risk of recurrence than radical nephrectomy. We aim to evaluate the clinical useful of nephrometry scores for predicting oncological outcomes in a large cohort of patients who underwent PN for renal cell carcinomas.

METHODS

Our analysis included patients who underwent PN for renal cell carcinoma in 21 French academic centers (2010-2020). RENAL, PADUA, and SPARE scores were calculated based on preoperative imaging. Uni- and multivariate cox models were performed to identify predictors of recurrence-free survival and overall survival. The area under the curve (AUC) was used to identify models with the highest discrimination. Decision curve analyses (DCAs) determined the net benefit associated with their use.

RESULTS

A total of 1927 patients were analyzed with a median follow-up of 32 months (14-45). RENAL score (p = 0.01), age (p = 0.002), histological type (p = 0.001), high nuclear grade (p = 0.001), necrotic component (p < 0.001), and positive margins (p = 0.005) were significantly related to recurrence in multivariate analyses. The discriminative performance of the 3 radiological scores was modest (65, 63, and 63%, respectively). All 3 scores showed good calibration, which, however, deteriorated with time. Decision curve analysis of the three models for the prediction of overall and recurrence-free survival was similar for all three scores and of limited clinical relevance.

CONCLUSION

The association between nephrometry scores and oncological outcomes after NP is very weak. The use of these scores for predicting oncological outcomes in routine practice is therefore of limited clinical value.

Prediction of Fuhrman nuclear grade for clear cell renal carcinoma by a multi-information fusion model that incorporates CT-based features of tumor and serum tumor associated material

PURPOSE

Prediction of Fuhrman nuclear grade is crucial for making informed herapeutic decisions in clear cell renal cell carcinoma (ccRCC). The current study aimed to develop a multi-information fusion model utilizing computed tomography (CT)-based features of tumors and preoperative biochemical parameters to predict the Fuhrman nuclear grade of ccRCC in a non-invasive manner.

METHODS

218 ccRCC patients confirmed by histopathology were retrospectively analyzed. Univariate and multivariate logistic regression analyses were performed to identify independent predictors and establish a model for predicting the Fuhrman grade in ccRCC. The predictive performance of the model was evaluated using receiver operating characteristic (ROC) curves, calibration, the 10-fold cross-validation method, bootstrapping, the Hosmer-Lemeshow test, and decision curve analysis (DCA).

RESULTS

R.E.N.A.L. Nephrometry Score (RNS) and serum tumor associated material (TAM) were identified as independent predictors for Fuhrman grade of ccRCC through multivariate logistic regression. The areas under the ROC curve (AUC) for the multi-information fusion model composed of the above two factors was 0.810, higher than that of the RNS (AUC 0.694) or TAM (AUC 0.764) alone. The calibration curve and Hosmer-Lemeshow test showed the integrated model had a good fitting degree. The 10-fold cross-validation method (AUC 0.806) and bootstrap test (AUC 0.811) showed the good stability of the model. DCA demonstrated that the model had superior clinical utility.

CONCLUSION

A multi-information fusion model based on CT features of tumor and routine biochemical indicators, can predict the Fuhrman grade of ccRCC using a non-invasive approach. This model holds promise for assisting clinicians in devising personalized management strategies.

Computed tomography-guided percutaneous microwave ablation for renal cell carcinoma: evaluating the performance of nephrometry scores

OBJECTIVES

The purpose of the current study is to evaluate the performance of RENAL and mRENAL scores, in the prediction of oncological outcomes in patients treated with microwave ablation (MWA) for (T1) renal cell carcinomas (RCC).

METHODS

Institutional database retrospective research identified 76 patients with a biopsy-proven solitary T1a (84%) or T1b (16%) RCC; all patients underwent CT-guided MWA ablation. Tumor complexity was reviewed by calculating RENAL and mRENAL scores.

RESULTS

The majority of the lesions were exophytic (82.9%), with > 7 mm nearness to the collecting system (53.9%), located posteriorly (73.6%), and lower to polar lines (61.8%). Mean RENAL and mRENAL scores were 5.7 (SD = 1.9) and 6.1 (SD = 2.1) respectively. Progression rates were significantly higher with greater tumor size (> 4 cm), with < 4 mm nearness to the collecting system, for tumors crossing a polar line and with the anterior location. None of the above was associated with complications. RENAL and mRENAL scores were significantly higher in patients with incomplete ablation. The ROC analysis showed the significant prognostic ability of both RENAL and mRENAL scores for progression. In both scores, the optimal cut-off point was 6.5. Univariate Cox regression analysis for progression showed a hazard ratio of 7.73 for the RENAL score and 7.48 for the mRENAL score.

CONCLUSION

The results of the present study show that the risk of progression was higher in patients with RENAL and mRENAL score of > 6.5, in T1b tumors, close to the collective system (< 4 mm), crossing polar lines and anterior location.

CLINICAL RELEVANCE STATEMENT

CT-guided percutaneous MWA is a safe and effective technique for the treatment of T1a renal cell carcinomas. Different morphometric parameters of RCC tumors including RENAL and mRENAL score > 6.5, size, proximity to the collecting system, and crossing of polar lines impact the efficacy of MWA and progression survival rates.

KEY POINTS

• The risk of progression is higher in patients with RENAL and mRENAL score > 6.5, in T1b tumors, close to the collective system (< 4 mm), crossing polar lines and anterior location. • The significant prognostic ability of the mRENAL score for progression was higher than the respective of the RENAL score. • Complications were not associated with any of the above factors.

Biological sex disparity in survival outcomes following treatment for renal cell carcinoma: A systematic review and meta-analysis

INTRODUCTION

Renal cell carcinoma (RCC), a type of kidney cancer has biological sex-based differences that play a role in cancer incidence. Specifically, the incidence of urinary system cancers in men is two times greater than in women, while the incidence of genital cancers is three times greater. There is conflicting epidemiologic and limited evidence in the literature to suggest apparent biological sex discrepancy. The primary objective of this review and meta-analysis is to synthesize evidence to understand biological sex disparity in the survival outcomes of RCC following any treatment intervention.

METHODS

A three-step search strategy was utilized in this review. We searched MEDLINE, EMBASE and PsycINFO databases for manuscript on biological sex differences in treatment outcomes. Study screening, critical appraisal, and data extraction were executed independently by pairs of reviewers among co-authors. Studies that had any form of treatment modality in the management of RCC were included. Study designs included observational studies in the form of prospective and retrospective studies that utilized cox proportional hazard assumption to conduct survival analysis. The data synthesis was carried out using the R metafor software package (Software version of 1.2.8) and Microsoft Office Excel 2019 package (Microsoft Corporation, USA). The random effects model was estimated using restricted maximum likelihood estimation (REML). Data synthesis included narrative review and meta-analysis.

RESULTS

We had 23 eligible studies for this review. On review of the full text, 35 studies were excluded due to irrelevances to measure estimates utilized. Finally, 12 studies were selected for the meta-analysis with a total of n = 21,2453 individuals. Females had a better survival outcome following a treatment intervention for RCC than their male counterpart [Mean effect size = -0.1737 (95 % CI: -0.2524, -0.0949)].

CONCLUSION

Females were more likely to be cancer free than their male counterpart following treatment for RCC. This finding will inform appropriate decision making for stakeholders.

Percutaneous Ablation of T1 Renal Masses: Comparative Local Control and Complications after Radiofrequency and Cryoablation

The efficacy and complication rates of percutaneous radiofrequency ablation (RFA) and cryoablation (CA) in the treatment of T1 renal masses in two Northern Italy hospitals were retrospectively investigated. Eighty-two patients with 80 T1a tumors and 10 T1b tumors treated with thermal ablation from 2015 through 2020 were included. A total of 43 tumors in 38 patients were treated with RFA (2.3 ± 0.9 cm), and 47 tumors in 44 patients were treated with CA (2.1 ± 0.8 cm). The mean follow-up observation period was 26 ± 19 months. The major complications and efficacy, as measured using the technical success and local tumor recurrence rates, were recorded. There were three (6.9%) technical failures with RFA and one (2.1%) with cryoablation (p = 0.30). Among the 40 tumors that were successfully treated with RFA, 1 tumor (2.5%) developed local tumor recurrence; 5/46 tumors that were treated with cryoablation (10.8%) developed local tumor recurrence (p = 0.17). T1b lesions (4.0 ± 0.7 cm) resulted in 1/6 technically unsuccessful cases with RFA and 0/4 with CA. No recurrent disease was detected in the T1b lesions. Major complications occurred after 2.3% (1/43) of RFAs and 0/47 of cryoablation procedures. RFA and cryoablation are both effective in the treatment of renal masses. Major complications with either procedure are uncommon.

Predicting Peri-Operative Outcomes in Patients Treated with Percutaneous Thermal Ablation for Small Renal Masses: The SuNS Nephrometry Score

Our objective was to develop a new, simple, and ablation-specific nephrometry score to predict peri-operative outcomes and to compare its predictive accuracy to PADUA and RENAL scores. Overall, 418 patients were treated with percutaneous thermal ablation (microwave and radiofrequency) between 2008 and 2021. The outcome of interest was trifecta status (achieved vs. not achieved): incomplete ablation or Clavien-Dindo ≥ 3 complications or postoperative estimated glomerular filtration rate decrease ≥ 30%. First, we validated the discrimination ability of the PADUA and RENAL scoring systems. Second, we created and internally validated a novel scoring (SuNS) system, according to multivariable logistic regression models. The predictive accuracy of the model was tested in terms of discrimination and calibration. Overall, 89 (21%) patients did not achieve trifecta. PADUA and RENAL scores showed poor ability to predict trifecta status (c-indexes 0.60 [0.53-0.67] and 0.62 [0.55-0.69], respectively). We, therefore, developed the SuNS model (c-index: 0.74 [0.67-0.79]) based on: (1) contact surface area; (2) nearness to renal sinus or urinary collecting system; (3) tumour diameter. Three complexity classes were created: low (3-4 points; 11% of no trifecta) vs. moderate (5-6 points; 30% of no trifecta) vs. high (7-8 points; 65% of no trifecta) complexity. Limitations include the retrospective and single-institution nature of the study. In conclusion, we developed an immediate, simple, and reproducible ablation-specific nephrometry score (SuNS) that outperformed PADUA and RENAL nephrometry scores in predicting peri-operative outcomes. External validation is required before daily practice implementation.

Percutaneous cryoablation versus partial nephrectomy for cT1b renal tumors: An inverse probability weight analysis

PURPOSE

To investigate differential clinical outcomes in patients treated with partial nephrectomy (PN) vs. percutaneous cryoablation (PCA) for cT1b renal tumors.

MATERIALS AND METHODS

We retrospectively analyzed the records of 119 patients who had undergone PN (n = 90) or PCA (n = 29) for cT1b renal tumors. Inverse probability weighting (IPW) was used for balancing patient demographics, including renal function and tumor complexity. Perioperative complications, renal function preservation rates, and oncological outcomes such as local recurrence-free, metastasis-free, cancer-specific, and overall survival were compared using IPW-adjusted restricted mean survival times (RMSTs).

RESULTS

PCA was more likely to be selected for octogenarians (odds ratio: 11.4, 95% confidence interval [CI]: 3.33-45.1). During the median follow-up of 43 months in the PCA group and 36.5 months in the PN group, unablated local residue or local recurrence was noted in 6 patients in the PCA group and local recurrence was noted in 4 patients in the PN groups. Of the 6 patients in the PCA group, 4 underwent salvage PCA, and local control had been achieved at the last visit. In the IPW-adjusted population, PCA had significantly worse local recurrence-free survival compared with PN (IPW-adjusted RMST difference: -22.7 months, 95% CI: -45.3 to -0.4, P = 0.046). IPW-adjusted RMST for metastasis-free survival (P = 0.23), cancer-specific survival (P = 0.77), and overall survival (P = 0.11) did not differ between PCA and PN. In addition, PN was not a predictor for local control failure at the last visit (odds ratio: 0.30, 95%CI: 0.05-1.29). There were no statistically significant differences between PN and PCA in renal function preservation or overall/severe complication rates.

CONCLUSIONS

In patients with cT1b renal tumor, although the local recurrence rate is higher for PCA than for PN, PCA provides comparable distant oncologic outcomes. PCA can be an alternative treatment option for elderly, comorbid patients, even those with cT1b renal tumors.

Long-term outcomes of cryoablation for biopsy-proven T1 stage renal cell carcinoma

Background

To summarize our clinical experience of cryoablation in renal cell carcinoma (RCC) of Chinese population and to evaluate the long-term outcomes of laparoendoscopic single-site (LESS) cryoablation (LCA) as well as percutaneous CT-guided cryoablation (PCA) for biopsy-proven T1a and T1b RCC.

Methods

This was a multi-center, retrospective study investigating T1 stage RCC patients from 2011 to 2021. The patients were treated by LCA or PCA according to individual situation. Overall survival (OS), cancer-related survival (CSS), and progression-free survival (PFS) were evaluated for oncological outcomes, and kidney function, complications, and hospital stay were used to estimate technical outcomes.

Results

A total of 163 consecutive patients were included. Among them, 59 cases were treated by LCA and PCA was performed in 104 cases. All operations were processed successfully. Mean diameter of the mass was (2.9±1.4) cm; median blood volume was 45ml (10~200 ml). The mean operation time was 84.0 ± 24.5 min. The median postoperative hospital stay was 3 days (1~6 days). Compared with LCA, procedure time of PCA was shortened, the volume of bleeding was reduced, and the hospital stay was decreased. The overall adverse events rate was 9.8% (16/163). The mean preoperative and postoperative eGFR of LCA were 77.6±15.3 ml/min and 75.6±17.4 ml/min, respectively. Analogously, the values of PCA were 78.7±12.9 ml/min and 76.7±14.3 ml/min. Mean follow-up time was 64.2 ± 30.2 months (range, 7–127 months). Local recurrence was observed in 13 patients (8.0%), 4 (6.8%) cases of LCA and 9 (8.7%) cases of PCA. PFS at 5 and 10 years were 95.5% and 69.2% for LCA and 96.7% and 62.8% for PCA. In total, 26 patients (16.0%) (11 patients from LCA and 15 from PCA) died throughout the follow-up period. OS at 5 and 10 years were 93.8% and 31.4% for LCA, and 97.4% and 52.7% for PCA. Six patients (3.7%) (3 cases from LCA and 3 from PCA) died of metastatic RCC. CCS for LCA were 98.0% and 82.8% at 5 and 10 years, while the data were 100% and 86.4% for PCA.

Conclusion

LCA and PCA for T1 stage RCC provides satisfactory long-term oncological and renal function preservation outcomes, with acceptable complication rates.

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.

Imaging Tool for Predicting Renal Clear Cell Carcinoma Fuhrman Grade: Comparing R.E.N.A.L. Nephrometry Score and CT Texture Analysis

Background

Clear cell renal cell carcinoma (ccRCC) is the most common renal malignant tumor. Preoperative imaging boasts advantages in diagnosing and choosing treatment methods for ccRCC.

Purpose

This study is aimed at building models based on R.E.N.A.L. nephrometry score (RNS) and CT texture analysis (CTTA) to estimate the Fuhrman grade of ccRCC and comparing the advantages and disadvantages of the two models.

Materials and Methods

143 patients with pathologically confirmed ccRCC were enrolled. All patients were stratified into Fuhrman low-grade and high-grade groups with complete CT data and R.E.N.A.L. nephrometry scores. CTTA features were extracted from the ROI delineated at the largest tumor level, and RNS and CTTA features were included in the logistic regression model, respectively.

Results

RNS model constructed based on multivariate logistic regression analysis showed that 3 pts for R-scores, 2 pts for E-scores, and 3 pts for L-scores were significant indicators to predict high-grade ccRCC, the AUC of RNS model was 0.911, and the sensitivity and specificity were 71.11% and 83.67%, respectively. The CTTA-model confirmed energy, kurtosis, and entropy as independent predictive factors, and the AUC of CTTA model was 0.941, with an optimal sensitivity and specificity of 84.44% and 93.88%.

Conclusions

R.E.N.A.L. nephrometry score has a certain provocative effect on the Fuhrman pathological grading of ccRCC. As a potential emerging technology, CTTA is expected to replace R.E.N.A.L. nephrometry score in evaluating patients' Fuhrman classification, and this approach might become an available method for assisting clinicians in choosing appropriate operation.

A Clinical Decision Aid to Support Personalized Treatment Selection for Patients with Clinical T1 Renal Masses: Results from a Multi-institutional Competing-risks Analysis

BACKGROUND

Personalized treatment for clinical T1 renal cortical masses (RCMs) should take into account competing risks related to tumor and patient characteristics.

OBJECTIVE

To develop treatment-specific prediction models for cancer-specific mortality (CSM), other-cause mortality (OCM), and 90-d Clavien grade ≥3 complications across radical nephrectomy (RN), partial nephrectomy (PN), thermal ablation (TA), and active surveillance (AS).

DESIGN, SETTING, AND PARTICIPANTS

Pretreatment clinical and radiological features were collected for consecutive adult patients treated with initial RN, PN, TA, or AS for RCMs at four high-volume referral centers (2000-2019).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prediction models used competing-risks regression for CSM and OCM and logistic regression for 90-d Clavien grade ≥3 complications. Performance was assessed using bootstrap validation.

RESULTS AND LIMITATIONS

The cohort comprised 5300 patients treated with RN (n = 1277), PN (n = 2967), TA (n = 476), or AS (n = 580). Over median follow-up of 5.2 yr (interquartile range 2.5-8.7), there were 117 CSM, 607 OCM, and 198 complication events. The C index for the predictive models was 0.80 for CSM, 0.77 for OCM, and 0.64 for complications. Predictions from the fitted models are provided in an online calculator (https://small-renal-mass-risk-calculator.fredhutch.org). To illustrate, a hypothetical 74-yr-old male with a 4.5-cm RCM, body mass index of 32 kg/m², estimated glomerular filtration rate of 50 ml/min, Eastern Cooperative Oncology Group performance status of 3, and Charlson comorbidity index of 3 has predicted 5-yr CSM of 2.9-5.6% across treatments, but 5-yr OCM of 29% and risk of 90-d Clavien grade 3-5 complications of 1.9% for RN, 5.8% for PN, and 3.6% for TA. Limitations include selection bias, heterogeneity in practice across treatment sites and the study time period, and lack of control for surgeon/hospital volume.

CONCLUSIONS

We present a risk calculator incorporating pretreatment features to estimate treatment-specific competing risks of mortality and complications for use during shared decision-making and personalized treatment selection for RCMs.

PATIENT SUMMARY

We present a risk calculator that generates personalized estimates of the risks of death from cancer or other causes and of complications for surgical, ablation, and surveillance treatment options for patients with stage 1 kidney tumors.

Imaging considerations for thermal and radiotherapy ablation of primary and metastatic renal cell carcinoma

Ablative (percutaneous and stereotactic) thermal and radiotherapy procedures for management of both primary and metastatic renal cell carcinoma are increasing in popularity in clinical practice. Data suggest comparable efficacy with lower cost and morbidity compared to nephrectomy. Ablative therapies may be used alone or in conjunction with surgery or chemotherapy for treatment of primary tumor and metastatic disease. Imaging plays a crucial role in pre-treatment selection and planning of ablation, intra-procedural guidance, evaluation for complications, short- and long-term post-procedural surveillance of disease, and treatment response. Treatment response and disease recurrence may differ considerably after ablation, particularly for stereotactic radiotherapy, when compared to conventional surgical and chemotherapies. This article reviews the current and emerging role of imaging for ablative therapy of renal cell carcinoma.

Selective Arterial Embolization with N-Butyl Cyanoacrylate Prior to CT-Guided Percutaneous Cryoablation of Kidney Malignancies: A Single-Center Experience

The study’s purpose was to assess the safety, feasibility and efficiency of selective arterial embolization (SAE) using N-butyl cyanoacrylate (NBCA) glue before percutaneous cryoablation (PCA) of renal malignancies in patients whose tumor characteristics and/or comorbidities resulted in an unacceptable risk of bleeding. In this single-center retrospective study of 19 consecutive high-risk patients (median age, 74 years) with renal malignancies managed in 2017–2020 by SAE with NBCA followed by PCA, data about patients, tumor and procedures characteristics, complications, renal function and hemoglobin concentration before and after treatment, as well as recurrence were collected. Charlson comorbidity index was ≥4 in 89.5% of patients. Ten patients were treated by antiplatelet and/or anticoagulant therapy. Median tumor largest diameter was 3.75 cm (range, 1–6.5 cm) and R.E.N.A.L. nephrometry score was ≥7 in 80%, indicating substantial tumor complexity. No major complications were recorded and minor complications occurred in 7 patients. No residual tumor was found at 6-week imaging follow-up in 18/19 patients. Tumor recurrence was visible in 1/16 patients at 6-month imaging follow-up. No significant difference was found for renal function after treatment (p = 0.07), whereas significant decrease in hemoglobin concentration was noted (p = 0.00004), although it was relevant for only one patient who required only blood transfusion and no further intervention. SAE prior to PCA is safe and effective for managing renal malignancies in high-risk patients.

sABLATE: a simplified ABLATE score for prediction of complications and outcome in percutaneous thermal ablation of renal lesions

The aim of the study is to evaluate the performance of a simplified ABLATE score (sABLATE) in predicting complications and outcome with respect to RENAL, mRENAL, and ABLATE scores. This study included 136 renal lesions in 113 patients (M:F ratio = 2.5; mean age 70.8 years). 98 tumors underwent cryoablation at San Raffaele hospital between 01/2015 and 03/2020, while 37 underwent microwave ablation at San Paolo or Policlinico hospitals between 07/2016 and 03/2020. RENAL, mRENAL, ABLATE, and sABLATE scores were calculated using pre-procedural imaging. Data regarding complications and follow-up were registered. Mann-Whitney U test, ROC analyses, and logistic regression analyses were used for complications. Cox-regression analyses were performed for outcome. Mean tumor diameter was 23.2 mm. Mean and median RENAL, mRENAL, ABLATE, and sABLATE scores were 6.8 and 7, 6.9 and 7, 5.3, and 5, and 3.5 and 3, respectively. During a mean follow-up of 21.9 months (range 1-73), we registered 7 complications, 3 cases of residual disease, and 10 local tumor progressions. Mann-Whitney U test p values for complications for RENAL, mRENAL, ABLATE, and sABLATE were 0.51, 0.49, 0.66, and 0.056, respectively. ROC analyses for complications showed an AUC for RENAL, mRENAL, ABLATE, and sABLATE of 0.57, 0.57, 0.55, and 0.71, respectively. Regarding outcome, HR and p values of Cox-regression analyses were 1.30 and 0.36 for RENAL, 1.33 and 0.35 for mRENAL, 2.16 and 0.01 for ABLATE, 2.29 and 0.004 for sABLATE. sABLATE was the only score close to significance for complications, representing a progress even if not definitive. Regarding outcome, ABLATE confirmed its value, and sABLATE maintained validity despite being a simplification.

External Validation of the Renal Ablation-Specific (MC)2 Risk Scoring System in Predicting Complications from Percutaneous Renal Cryoablation

PURPOSE

The (MC)2 score is a renal ablation-specific risk scoring system to predict major complications from percutaneous renal cryoablation (PRCA). However, it is untested in an external population of patients. The purpose of this study is to validate the ability of the (MC)2 score to predict major complications after PRCA in an external population.

MATERIALS AND METHODS

Retrospective review of patients who underwent PRCA from 2004 to 2019. Patient demographics, medical histories, and tumor characteristics were collected. The (MC)2 score was calculated and patients were assigned to low risk (< 5), moderate risk (5-8) and high-risk (> 8) groups. Complications were recorded. Major complications were classified according to CIRSE guidelines.

RESULTS

Two hundred and one patients [M = 116; F = 85; median age = 65 (range 27-90)] met inclusion criteria. Eleven patients (5.5%) developed major complications and 50 patients (24.9%) developed minor complications. Of patients with major complications, mean tumor diameter was 39 mm (± 10.4), seven patients (63.6%) had a central tumor, four patients (36.4%) had complicated diabetes, and one patient (9.1%) had a prior MI. Major complication rates were 2.1%, 14%, and 14.3% in the (MC)2 low risk, moderate risk, and high risk groups, respectively. The mean (MC)2 score for patients with major complications [6.2 (± 2.4)] was higher than the mean score for patients with minor complications [4.7 (± 2.4) (p = 0.07)] and no complications [3.9 (± 1.9) (p < 0.01)]. The area under the ROC curve to predict major complications was 0.78.

CONCLUSION

The (MC)2 risk scoring system appropriately identifies patients at risk for major complications from PRCA in this external patient population.

Asian Conference on Tumor Ablation guidelines for renal cell carcinoma

Thermal ablation has been established as an alternative treatment for renal cell carcinoma (RCC) in patients who are poor candidates for surgery. However, while American and European guidelines have been established for American and European patients, respectively, no ablation guidelines for Asian patients with RCCs have been established many years after the Asian Conference on Tumor Ablation (ACTA) had been held. Given that Western guidelines are difficult to apply to Asian patients due to differences in body habitus, economic status, and insurance systems, the current review sought to establish the first version of the ACTA guidelines for treating a RCC with thermal ablation.

Percutaneous Microwave Ablation of Category T1a Renal Cell Carcinoma: Intermediate Results on Safety, Technical Feasibility, and Clinical Outcomes of 119 Tumors

OBJECTIVE. The purpose of this study was to assess the safety, technical results, and clinical outcomes of CT-guided percutaneous microwave ablation of category T1a renal cell carcinoma. MATERIALS AND METHODS. This retrospective study investigated consecutive patients who underwent CT-guided microwave ablation for T1a renal cell carcinoma from October 2015 to May 2019. Patient demographics including tumor characteristics, comorbidities, technical details, and clinical outcomes were evaluated. Local progression-free survival and overall survival rates were estimated using the Kaplan-Meier method. RESULTS. One hundred-six patients including 70 men (mean age, 68.5 ± 8.9 [SD] years; range, 49-86 years) and 36 women (mean age, 69.5 ± 10.0 years; range, 50-88 years) with an overall mean age of 68.8 ± 9.2 years (range, 49-88 years) with 119 T1a renal cell carcinomas were treated with CT-guided microwave ablation. Technical success was achieved for 100% of the tumors. Complete response was achieved in 101 (95.3%) patients and partial response was achieved in five (4.7%) patients. Local progression-free survival was 100.0%, 92.8%, and 90.6% at 1, 2, and 3 years, respectively. Overall survival was 99.0%, 97.7%, and 94.6% at 1, 2, and 3 years, respectively. Six patients (5.7%) had seven complications (five with Clavien-Dindo Grade I, Society of Interventional Radiology [SIR] category A, two with Clavien-Dindo Grade III, SIR category B) within 30 days of the procedure. CONCLUSION. CT-guided percutaneous microwave ablation is associated with high rates of technical success, excellent local progression-free survival and overall survival, and a low complication rate for category T1a renal cell carcinoma.

Percutaneous Thermal Ablation for Treatment of T1a Renal Cell Carcinomas

Based on Surveillance, Epidemiology, and End Results studies, most renal cancers are low grade and slow growing. Long-term, single-center studies show excellent outcomes for T1a renal cell carcinoma (RCC), comparable to partial nephrectomy without affecting renal function and with much lower rates of complications. However, there are no multicenter randomized controlled trials of multiple ablative modalities or comparison with partial nephrectomy, and most studies are single-arm observational studies with short-term and intermediate follow-up. For treatment of stage T1a RCC, percutaneous TA is an effective alternative to surgery with preservation of renal function, low risk, and comparable overall and disease-specific survival.

Percutaneous Microwave Ablation of Stage T1b Renal Cell Carcinoma: Short-Term Assessment of Technical Feasibility, Short-Term Oncologic Outcomes, and Safety

Purpose: To report on the safety, technical results, and oncologic outcomes of computed tomography guided percutaneous microwave ablation of stage cT1b renal cell carcinoma. Materials and Methods: This single-center retrospective study investigated consecutive patients with T1b renal cell carcinoma who were treated with CT guided percutaneous microwave ablation between December 2015 and May 2019. Patient baseline characteristics, tumor biologic features, technical parameters, clinical outcomes, and complications were recorded and evaluated. Local tumor progression-free survival and overall survival rates were estimated using the Kaplan-Meier methods. Results: This study included 23 patients (18 men [mean age ± standard deviation, 74.6 years ±10.2; range 58-89 years] and 5 women [mean age, 71.6 years ±10.1; range 62-86 years]; overall mean age, 74.0 years ±10.0; range 58-89 years) with 23 T1b renal cell carcinomas. Primary technical success was achieved in 20/23 (87%) patients. Secondary technical success was achieved in 3/3 (100%) patients. Local tumor progression-free survival was 100.0%, 90.9%, and 90.9% at 1, 2, and 3 years, respectively. Overall survival was 95.2%, 85.7%, and 71.4% at 1, 2, and 3 years, respectively. There were 2 (8.7%) complications; both were classified as minor complications according to the Society of Interventional Radiology grading system. Conclusions: Computed tomography guided percutaneous microwave ablation for T1b renal cell carcinoma is associated with high rates of technical success, excellent local tumor progression-free survival, short-term survival and overall survival, and low complication rates.

Percutaneous Microwave Ablation of Histologically Proven T1 Renal Cell Carcinoma

Objectives

To assess the safety and efficacy of percutaneous microwave ablation (MWA) of histologically proven T1 renal cell carcinoma (RCC).

Methods

We analysed patients with a histologically proven RCC (≤ 7 cm) treated by MWA from April 2012–April 2018. Primary and secondary efficacy, local tumour recurrence (LTR), morbidity and mortality were reported. Efficacy was defined as no residual tumour enhancement on follow-up imaging 1 month after the first ablation (primary efficacy) and after re-ablation(s) for residual disease (secondary efficacy). Adverse events (AE) were registered by the Clavien–Dindo classification and the common terminology criteria for AE. Univariable and multivariable logistic regression analyses were performed to investigate a relation among pre-treatment factors incomplete ablation and complications.

Results

In 100 patients, a total of 108 RCCs (85 T1a and 23 T1b) were treated by MWA. Median size was 3.2 cm (IQR 2.4–4.0). Primary efficacy was 89% (95%CI 0.81–0.94) for T1a lesions and 52% (95%CI 0.31–0.73) for T1b lesions (p < 0.001). Fifteen lesions (7 T1a) were re-ablated for residual disease by MWA in one (n = 13) and two (n = 2, both T1b) sessions resulting in secondary efficacy rates of 99% (T1a) and 95% (T1b, p = 0.352). LTR occurred in four tumours (2 T1a, 2 T1b) after 10–60 months. Six (4%) AEs grade > 3–5 were observed (2 T1a, 4 T1b, p = 0.045). Multivariable analysis showed that mR.E.N.A.L. nephrometry was independently associated with incomplete ablation (p = 0.012).

Conclusion

Microwave ablation is safe and effective for T1a and T1b RCC lesions with a significantly lower primary efficacy for T1b lesions.

Percutaneous Image-guided Thermal Ablation for Renal Cell Carcinoma

Nephrectomy is the gold standard for the treatment of renal cell carcinoma (RCC). However, some patients are not suitable candidates for nephrectomy because of high surgical risk, reduced renal function, or the presence of multiple renal tumors. Percutaneous image-guided thermal ablation, including cryoablation and radiofrequency ablation, is a minimally invasive and highly effective treatment and can be used to treat RCC in patients who are not good candidates for surgery. This article will review percutaneous image-guided thermal ablation for RCC, covering treatment indications, ablation modalities and techniques, oncologic outcomes, and possible complications. In addition, the characteristics of each ablation modality and its comparison with nephrectomy are also presented.

Imaging of Small Renal Masses before and after Thermal Ablation

Thermal ablation of small renal masses is increasingly accepted as an alternative to partial nephrectomy, particularly in patients with multiple comorbidities. Many professional societies support this alternate treatment with updated guidelines. Before performing thermal ablation, it is important to stratify risk and assess technical feasibility by evaluating tumor imaging features such as size, location, and centrality. Routine postablation imaging with CT or MRI is necessary for assessment of residual or recurrent tumor, evidence of complications, or new renal masses outside the ablation zone. The normal spectrum and evolution of findings at CT and MRI include a halo appearance of the ablation zone, ablation zone contraction, and ablation zone calcifications. Tumor recurrence frequently manifests at CT or MRI as new nodular enhancement at the periphery of an expanding ablation zone, although it is normal for the ablation zone to enlarge within the first few months. Recognizing early tumor recurrence is important, as small renal masses are often easily treated with repeat ablations. Potential complications of thermal ablation include vascular injury, urine leak, ureteral stricture, nerve injury, and bowel perforation. The risk of these complications may be related to tumor size and location.^©RSNA, 2019.

Association among the R.E.N.A.L. nephrometry score and clinical outcomes in patients with small renal masses treated with percutaneous contrast enhanced ultrasound radiofrequency ablation

Introduction

An association between the R.E.N.A.L. nephrometry score (RNS) and clinical outcomes in patients with a small renal mass (SRM) has been proposed. We analyzed clinical outcomes according to the RNS in patients with a SRM treated with percutaneous contrast enhanced ultrasound (CEUS) radiofrequency ablation (RFA).

Material and methods

Patients with a SRM, who underwent RFA between January 2005 and March 2015, were retrospectively identified. The association between RNS and clinical outcomes was evaluated using parametric and non-parametric analysis.

Results

We analyzed 163 SRMs in 149 consecutive patients. The mean age was 71.7 years. Mean follow-up time was 33.3 months ±20.6 (2-102). The mean RNS was 5.6 ±1.52 (4-11). A total of 121 (74.2%) cases were of low complexity and 42 (25.8%) were medium complexity. We identified 11 cases of tumor persistence (6.7%). The mean RNS was 5.58 in the cases with no persistence and 5.73 in the cases with persistence (p = 0.788). We identified 15 (9.2%) cases of recurrence. The mean RNS was 5.57 ±0.1 (4-11) in the cases without recurrence and 5.73 ±0.4 (4-9) in recurrence cases (p = 0.804). Of the 76 biopsy proven RCC cases, 8 (10.5%) cases of recurrence were observed, 5 in the low complexity group and 3 in the medium complexity group (p = 0.690). A total of 9 (5.5%) cases of complications were observed, with 5 (4.3%) in the low complexity group and 4 cases in the medium complexity group (p = 0.23). The mean length of stay was 1.5 days with a significant difference between low and medium complexity groups (1.3 vs. 2.1 days, p = 0.02). The mean difference between preoperative eGFR and estimated eGFRat 12 months was -3.08 mL / min ±13.3 (-49.4-34.1) and was significant (p = 0.008).However, this variation did not show significant differences between the low and medium complexity groups (p = 0.936). All-cause mortality was 11.7%, 14 cases (11.6%) in the low complexity group and 5 (11.9%) in the medium complexity group (p = 1.0). No cases of renal cell carcinoma (RCC) specific mortality were identified.

Conclusions

The RNS was not associated with tumor persistence, recurrence, cancer specific mortality, complications or renal function 12 months after the first treatment, showing significant difference only in length of hospital stay between low and medium complexity groups.

Systematic Review of Contemporary Evidence for the Management of T1 Renal Cell Carcinoma: What IRs Need to Know for Kidney Cancer Tumor Boards

Renal cell carcinoma is a relatively common malignancy, with 60 to 70 thousand cases a year in the United States alone. Increased utilization of cross-sectional imaging has led to an increase in the number of early renal cell cancers seen by the medical establishment. In addition, certain patient populations have an increased risk of developing kidney cancers which may mandate aggressive screening protocols. This article discusses the epidemiology of renal cell cancers; discusses the current management guidelines from multiple specialty societies; discusses some of the surgical and interventional techniques used in the treatment of such lesions; and provides a review of the literature regarding treatments of early-stage renal cell cancers.

Retreatment after focal therapy for failure: a bridge too far?

PURPOSE OF REVIEW

To summarize the current knowledge about the evaluation of disease persistence and recurrence after focal therapy ablation (FTA) for small renal masses and to assess the outcomes and complications of related treatment options.

RECENT FINDINGS

FTA procedures continuously increased over the last 20 years, being now performed in more than one on 10 patients with T1a renal cell carcinoma. Disease recurrence seems to occur more often following radiofrequency ablation (RFA) compared with cryoablation. Evidence about the management of disease recurrence is scarce. Treatment options are similar to those available for de novo renal cell carcinomas, and include reablation, partial or radical nephrectomy and observation. Reablation is feasible, safe and can be easily done in the majority of cases. Oncological outcomes of repeated ablation, although encouraging, remain mostly uninvestigated and unreported.

SUMMARY

In case of disease persistence or recurrence after FTA, observation may be an acceptable approach, reserving repeated ablation or surgery only in those exhibiting significant tumor growth. In these patients repeated ablation with RFA is safe and noninvasive. Surgery after FTA presents technical difficulties related to perinephric scarring, especially with regards to nephron-sparing surgery. This should be taken into consideration in patients' counseling as well as in decision-making process.

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.

Tumor location does not impact oncologic outcomes for percutaneous microwave ablation of clinical T1a renal cell carcinoma

OBJECTIVE

To evaluate the impact of anterior tumor location on oncologic efficacy, complication rates, and procedure duration for 151 consecutive biopsy-proven clinical T1a renal cell carcinoma (RCC) treated with percutaneous microwave (MW) ablation.

METHODS

This single-center retrospective study was performed under a waiver of informed consent. One hundred forty-eight consecutive patients (103 M/45 F; median age 67 years, IQR 61-73) with 151 cT1a biopsy-proven RCC (median diameter 2.4 cm, IQR 1.9-3.0) were treated with percutaneous MW ablation between March 2011 and August 2017. Patient and procedural data collected included Charlson comorbidity index (CCI), RENAL nephrometry score (NS), use of hydrodisplacement, MW antennas/generator output/time, and procedure time (PT). Data were stratified by anterior, posterior, and midline tumor location and compared with the Kruskal-Wallis or chi-squared tests. The Kaplan-Meier method was used for survival analyses.

RESULTS

Tumor size, NS, and use/volume of hydrodisplacement were similar for posterior and anterior tumors (p > 0.05). Patients with anterior tumors had a higher CCI (3 vs 4, p = 0.001). Median PT for posterior and anterior tumors was similar (100 vs 108 min, p = 0.26). Single session technical success and primary efficacy were achieved for all 151 tumors including 61 posterior and 67 anterior tumors. The 4 (3%) Clavien III-IV complications and 6 (4%) local recurrences were not associated with tumor location (p > 0.05). Three-year RFS, CSS, and OS were 95% (95% CI 0.87, 0.98), 100% (95% CI 1.0, 1.0), and 96% (95% CI 0.89, 0.98), respectively.

CONCLUSIONS

The safety and efficacy of percutaneous microwave ablation for anterior and posterior RCC are similar.

KEY POINTS

• The safety profile for percutaneous microwave ablation of anterior and posterior T1a renal cell carcinoma is equivalent. • Percutaneous microwave ablation of T1a renal cell carcinoma provides durable oncologic control regardless of tumor location. • Placement of additional microwave antennas and use of hydrodisplacement are associated with longer procedure times.

Organ-sparing procedures in GU cancer: part 1-organ-sparing procedures in renal and adrenal tumors: a systematic review

PURPOSE

Organ-sparing surgery (OSS) for the kidney and adrenals has emerged as the need for preservation of function is paramount in patients with poor functional reserve. As reports increasingly showed that oncological outcomes were equivalent to radical excision, elective OSS became a viable alternative in patients with otherwise normal reserve. In this review, we summarize the current knowledge of OSS for adrenal and renal tumors.

MATERIALS AND METHODS

PubMed, Web of Science and Cochrane Library Central Search were searched for recently published articles up to December 2017. The following keywords were used; "partial adrenalectomy", "adrenal sparing", "partial nephrectomy", "nephron sparing", "kidney/renal cancer".

RESULTS

Partial adrenalectomy became an attractive alternative to total adrenalectomy avoiding adrenal insufficiency. Both minimally invasive surgery and ablative techniques were increasingly reported for adrenal OSS with adequate residual adrenal function and excellent oncological outcome. Radical nephrectomy remained for many years as the gold standard of treatment for organ-confined renal cell carcinoma. As the need to reduce the impact on renal function, more conservative approaches were utilized. Soon, the non-inferiority of nephron-sparing surgery to that of radical excision became evident and elective partial nephrectomy was gaining ground as the standard of care for small renal masses in patients with normal contralateral kidneys.

CONCLUSIONS

Herein, we present a comprehensive review of the current status of OSS in renal and adrenal tumors.

Change in Nephrometry Scoring in Small Renal Masses (<4 cm) on Active Surveillance: Preliminary Observations From Tayside Active Surveillance Cohort (TASC) Study

RATIONALE AND OBJECTIVES

Prediction of growth, in particular knowing the possibility of aggressive cancer in small renal masses on active surveillance, remains poorly understood. The study was designed to determine whether serial nephrometry score measurements could predict possibility of aggressive malignancy (grade of cancer) in patients with small renal masses opting for active surveillance initially.

MATERIALS AND METHODS

One hundred sixteen patients between January 2000 and December 2016 undergoing partial nephrectomy were recruited. Out of these, 97 were analyzed using different nephrometry scoring systems. Measurement of nephrometry scores (Radius of tumors, Exo/Endophytic; Nearness of tumors to the collecting system or sinus; Anterior/posterior; Location in relation to polar lines, Preoperative Aspects and Dimensions Used for Anatomical, Centrality Index) was performed by two researchers. Among the patients opting for partial nephrectomy, 40 were on active surveillance for at least 12 months (mean 32; 12-60 months) before partial nephrectomy. Computed tomography scan images of these patients were retrieved and analyzed including comparison to histopathology.

RESULTS

Nephrometry scores measured on serial computed tomography scan images showed a significant correlation between change in score and grade of cancer on multivariate analysis (P value .001). Addition of multivariate analysis to nomogram based on change in size alone did not improve predictive value of area under the curve significantly.

CONCLUSIONS

Change in nephrometry scoring measurements correlates with grade of cancer in small renal masses but falls short of significantly predicting presence of malignancy or grade of cancer on nomogram in patients opting for active surveillance for small renal masses. At present, this approach may be inadequate for decision-making.

Magnetic resonance imaging (MRI) of the renal sinus

This article presents methods to improve MR imaging approach of disorders of the renal sinus which are relatively uncommon and can be technically challenging. Multi-planar Single-shot T2-weighted (T2W) Fast Spin-Echo sequences are recommended to optimally assess anatomic relations of disease. Multi-planar 3D-T1W Gradient Recalled Echo imaging before and after Gadolinium administration depicts the presence and type of enhancement and relation to arterial, venous, and collecting system structures. To improve urographic phase MRI, concentrated Gadolinium in the collecting systems should be diluted. Diffusion-Weighted Imaging (DWI) should be performed before Gadolinium administration to minimize T2* effects. Renal sinus cysts are common but can occasionally be confused for dilated collecting system or calyceal diverticula, with the latter communicating with the collecting system and filling on urographic phase imaging. Vascular lesions (e.g., aneurysm, fistulas) may mimic cystic (or solid) lesions on non-enhanced MRI but can be suspected by noting similar signal intensity to the blood pool and diagnosis can be confirmed with MR angiogram/venogram. Multilocular cystic nephroma commonly extends to the renal sinus, however, to date are indistinguishable from cystic renal cell carcinoma (RCC). Solid hilar tumors are most commonly RCC and urothelial cell carcinoma (UCC). Hilar RCC are heterogeneous, hypervascular with epicenter in the renal cortex compared to UCC which are centered in the collecting system, homogeneously hypovascular, and show profound restricted diffusion. Diagnosis of renal sinus invasion in RCC is critically important as it is the most common imaging cause of pre-operative under-staging of disease. Fat is a normal component of the renal sinus; however, amount of sinus fat correlates with cardiovascular disease and is also seen in lipomatosis. Fat-containing hilar lesions include lipomas, angiomyolipomas, and less commonly other tumors which engulf sinus fat. Mesenchymal hilar tumors are rare. MR imaging diagnosis is generally not possible, although anatomic relations should be described to guide diagnosis by percutaneous biopsy or surgery.

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.

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.

[Focal therapy for small renal masses : Observation, ablation or surgery]

BACKGROUND

The rising incidence of renal cell carcinoma, its more frequent early detection (stage T1a) and the increasing prevalence of chronic renal failure with higher morbidity and shorter life expectancy underscore the need for multimodal focal nephron-sparing therapy.

DISCUSSION

During the past decade, the gold standard shifted from radical to partial nephrectomy. Depending on the surgeon's experience, the patient's constitution and the tumor's location, the intervention can be performed laparoscopically with the corresponding advantages of lower invasiveness. A treatment alternative can be advantageous for selected patients with high morbidity and/or an increased risk of complications associated with anesthesia or surgery. Corresponding risk stratification necessitates previous confirmation of the small renal mass (cT1a) by histological examination of biopsy samples. Active surveillance represents a controlled delay in the initiation of treatment.

RESULTS

Percutaneous radiofrequency ablation (RFA) and laparoscopic cryoablation are currently the most common treatment alternatives, although there are limitations particularly for renal tumors located centrally near the hilum. More recent ablation procedures such as high intensity focused ultrasound (HIFU), irreversible electroporation, microwave ablation, percutaneous stereotactic ablative radiotherapy and high-dose brachytherapy have high potential in some cases but are currently regarded as experimental for the treatment of renal cell carcinoma.

Skin-to-tumor Distance Predicts Treatment Failure of T1A Renal Cell Carcinoma Following Percutaneous Cryoablation

OBJECTIVE

To determine the impact of skin-to-tumor (STT) distance on the risk for treatment failure following percutaneous cryoablation (PCA).

METHODS

We retrospectively reviewed patients who underwent PCA with documented T1a recurrent renal cell carcinoma (RCC) at 2 academic centers between 2005 and 2015. Patient demographics, tumor characteristics, and perioperative and postoperative course variables were collected. Additionally, we measured the STT distance by averaging the distance from the skin to the center of the tumor at 0°, 45°, and 90° on preoperative computed tomography imaging.

RESULTS

We identified 86 patients with documented T1a RCC. The mean age at the time of surgery was 69 years (range: 37-91 years), and the mean tumor size was 2.7 cm (range: 1.0-4.0 cm). With a mean follow-up of 24 months (range: 3-63 months), 11 (12.8%) treatment failures occurred. Patients with treatment failure had significantly higher mean STT distance than those without: 11.0 cm (range: 6.3-20.1 cm) compared to 8.4 cm (range: 4.4-15.2 cm), respectively (P = .002). STT distance was an independent predictor of treatment failure (odds ratio: 1.32, 95% confidence interval: 1.04-1.69, P = .029). STT distance greater than 10 cm had a fourfold increased risk of tumor treatment failure (odds ratio: 4.43, 95% confidence interval: 1.19-16.39, P = .018). Tumor size, R.E.N.A.L. Nephrometry score, and number of cryoprobes placed were not associated with treatment failure.

CONCLUSION

STT, an easily measured preoperative variable, may inform the risk of RCC treatment failure following PCA.

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.

Effect of Tumor Complexity and Technique on Efficacy and Complications after Percutaneous Microwave Ablation of Stage T1a Renal Cell Carcinoma: A Single-Center, Retrospective Study

Purpose To evaluate the effects of tumor complexity and technique on early and midterm oncologic efficacy and rate of complications for 100 consecutive biopsy-proved stage T1a renal cell carcinomas (RCCs) treated with percutaneous microwave ablation. Materials and Methods This HIPAA-compliant, single-center retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. Ninety-six consecutive patients (68 men, 28 women; mean age, 66 years ± 9.4) with 100 stage T1a N0M0 biopsy-proved RCCs (median diameter, 2.6 cm ± 0.8) underwent percutaneous microwave ablation between March 2011 and June 2015. Patient and procedural data were collected, including body mass index, comorbidities, tumor histologic characteristics and grade, RENAL nephrometry score, number of antennas, generator power, and duration of ablation. Technical success, local tumor progression, and presence of complications were assessed at immediate and follow-up imaging. The Kaplan-Meier method was used for survival analyses. Results Technical success was achieved for all 100 tumors (100%), including 47 moderately and five highly complex RCCs. Median clinical and imaging follow-up was 17 months (range, 0-48 months) and 15 months (range, 0-44 months), respectively. No change in estimated glomerular filtration rate was noted after the procedure (P = .49). There were three (3%) procedure-related complications and six (6%) delayed complications, all urinomas. One case of local tumor progression (1%) was identified 25 months after the procedure. Three-year local progression-free survival, cancer-specific survival, and overall survival were 88% (95% confidence interval: 0.52%, 0.97%), 100% (95% confidence interval: 1.0%, 1.0%), and 91% (95% confidence interval: 0.51%, 0.99%), respectively. Conclusion Percutaneous microwave ablation is an effective and safe treatment option for stage T1a RCC, regardless of tumor complexity. Long-term follow-up is needed to establish durable oncologic efficacy and survival relative to competing ablation modalities and surgery. ^© RSNA, 2017.

Utility of the RENAL index -Radius; Exophytic/endophytic; Nearness to sinus; Anterior/posterior; Location relative to polar lines- in the management of renal masses

CONTEXT

The growing incidence of renal masses and the wide range of available treatments require predictive tools that support the decision making process. The RENAL index -Radius; Exophytic/endophytic; Nearness to sinus; Anterior/posterior; Location relative to polar lines- helps standardise the anatomy of a renal mass by differentiating 3 groups of complexity. Since the introduction of the index, there have been a growing number of studies, some of which have been conflicting, that have evaluated the clinical utility of its implementation.

OBJECTIVE

To analyse the scientific evidence on the relationship between the RENAL index and the main strategies for managing renal masses.

ACQUISITION OF THE EVIDENCE

A search was conducted in the Medline database, which found 576 references on the RENAL index. In keeping with the PRISM Declaration, we selected 100 abstracts and ultimately reviewed 96 articles.

SYNTHESIS OF THE EVIDENCE

The RENAL index has a high degree of interobserver correlation and has been validated as a predictive nomogram of histological results. In active surveillance, the index has been related to the tumour growth rate and probability of nephrectomy. In ablative therapy, the index has been associated with therapeutic efficacy, complications and tumour recurrence. In partial nephrectomy, the index has been related to the rate of complications, conversion to radical surgery, ischaemia time, function preservation and tumour recurrence, a finding also observed in radical nephrectomy.

CONCLUSIONS

The RENAL index is an objective, reproducible and useful system as a predictive tool of highly relevant clinical parameters such as the rate of complications, ischaemia time, renal function and oncological results in the various currently accepted treatments for the management of renal masses.