Radiofrequency ablation (RFA) of renal cell carcinoma (RCC): experience in 200 tumours

Cost-Effectiveness Analysis Comparing Biopsy in Advance of Ablation with Concurrent Biopsy and Ablation for Small Renal Masses Measuring 1-3 cm

PURPOSE

To analyze the cost effectiveness of performing a renal mass biopsy in advance of ablation or concurrently with a percutaneous ablation procedure for the management of small renal masses (SRMs).

MATERIALS AND METHODS

A decision-analytic model was developed with a cohort of 65-year-old male patients with an incidental, unilateral 1-3 cm SRM. A decision tree modeled the first year of clinical intervention, after which patients entered a Markov model with a lifetime horizon. Patients were assumed to be treated in accordance with established clinical practice guidelines, including surveillance, repeat ablation for recurrence, and systemic therapy for metastasis. Healthcare cost and utility values were determined from published literature or local hospital estimates, discounted at 1.5%. Total lifetime costs were calculated from the perspective of a Canadian healthcare payer and converted to 2022 Canadian dollars (C$). The primary outcome was incremental cost-effectiveness ratio (ICER) at a willingness-to-pay threshold of C$50,000 per quality-adjusted life year (QALY) gained. The secondary outcome was ICER at a willingness-to-pay threshold of C$50,000 per life year (LY) gained.

RESULTS

Concurrent biopsy and ablation resulted in a gain of 16.4 quality-adjusted days, at an incremental cost of $386, with an ICER of C$8,494/QALY. The concurrent strategy was the dominant strategy for a prevalence of benign mass of <5%. Sequential biopsy and ablation was only cost-effective when LYs were not quality-adjusted and ablation cost was >C$4,300 or benign mass prevalence was >28%.

CONCLUSIONS

Concurrent biopsy and ablation is cost-effective relative to pretreatment diagnostic biopsy for management of incidental SRMs.

Recurrences after nephron-sparing treatments of renal cell carcinoma: a competing risk analysis

PURPOSE

To examine associations between ablative therapy (AT) and partial nephrectomy (PN) and the occurrence of local recurrence (LR), distant metastatic recurrence (DMR) and all-cause mortality in a nation-wide real-world population-based cohort of patients with nonmetastatic renal cell carcinoma (nmRCC).

METHODS

Data on 2751 AT- or PN-treated nmRCC tumours diagnosed during 2005-2018, representing 2701 unique patients, were obtained from the National Swedish Kidney Cancer Register. Time to LR/DMR or death with/without LR/DMR was analysed using Cox regression models.

RESULTS

During a mean of 4.8 years follow-up, LR was observed for 111 (4.0%) tumours, DMR for 108 (3.9%) tumours, and death without LR/DMR for 206 (7.5%) tumours. AT-treated tumours had a 4.31 times higher risk of LR (P < 0.001) and a 1.91 times higher risk of DMR (P = 0.018) than PN-treated, with no significant differences in risk of death without LR/DMR. During a mean of 3.2 and 2.5 years of follow-up after LR/DMR, respectively, 24 (21.6%) of the LR cases and 56 (51.9%) of the DMR cases died, compared to 7.5% in patients without LR/DMR. There were no significant differences between AT- and PN-treated regarding risks of early death after occurrence of LR or DMR.

CONCLUSION

AT treatment of patients with nmRCC implied significantly higher risks of LR and DMR compared with PN treatment. To minimize the risks of LR and DMR, these results suggest that PN is preferred over AT as primary treatment, supporting the EAU guidelines to recommended AT mainly to frail and/or comorbid patients.

Image-guided Ablative Procedures

Various image-guided ablative procedures include chemical and thermal ablation techniques and irreversible electroporation. These have been used for curative intent for small tumours and palliative intent for debulking, immunogenicity and pain control. Understanding these techniques is critical to avoiding complications and achieving superior clinical outcomes. Additionally, combination with immunotherapy and chemotherapies is rapidly evolving. There are numerous opportunities in interventional radiology to advance ablation techniques and seamlessly integrate into current treatment regimens for both benign and malignant tumours.

Efficacy of Radiofrequency Ablation in Autonomous Functioning Thyroid Nodules: A Comprehensive Systematic Review and Meta-analysis

BACKGROUND

Radiofrequency ablation (RFA) is a minimally invasive outpatient procedure that has recently emerged as a treatment option for autonomous functioning thyroid nodules (AFTNs), offering a less invasive alternative to surgery. The objective of this systematic review and meta-analysis is to evaluate the efficacy of RFA for AFTNs.

METHOD

Global databases of PubMed, Scopus, Embase, Web of Science, and Cochrane Library were systematically searched from 1990 until January 5, 2024, for studies on AFTNs undergoing RFA that presented volume reduction ratio (VRR) for at least one of 1, 3, 6 or 12 months post-operative follow-up with the results presented as means. The primary outcomes were VRR and TSH normalization rate, and the secondary outcomes were the cosmetic score, symptom score, and post-procedure complications. Heterogeneity was assessed by Cochrane and I2 statistics, and a random-effects model was used for meta-analysis. The study protocol was registered on PROSPERO (CRD42024499932).

RESULTS

A total of 10 eligible studies with a total sample size of 254 were included. The pooled VRR after 1, 3, 6, and 12 months of follow-up post-treatment with RFA was 46.6% (95% CI: 40.3-52.9%), 62% (95% CI: 57.6-66.4%), 67.4% (95% CI:62.3-72.6%), and 77.2% (95% CI: 79.2-81.5%), respectively. The overall rate of TSH normalization was 76.4% (95% CI: 58.1-88.4%). Based on included studies the overall rate of subclinical hypothyroidism as one of the most important side effects of this method was 4% (95% CI: 1.9%-8.1%).

CONCLUSION

RFA emerges as a promising non-surgical treatment for AFTNs, showing high rates of TSH normalization, tumor size reduction, and improved cosmetic and symptom scores. However, further research is needed to compare RFA with surgical methods and assess long-term outcomes.

Magnetic-Resonance-Imaging-Guided Cryoablation for Solitary-Biopsy-Proven Renal Cell Carcinoma: A Tertiary Cancer Center Experience

BACKGROUND

Our purpose is to evaluate the long-term oncologic efficacy and survival rates of MRI-guided cryoablation for patients with biopsy-proven cT1a renal cell carcinoma (RCC).

MATERIALS AND METHODS

We retrospectively reviewed our renal ablation database between January 2007 and June 2021 and only included patients with solitary-biopsy-proven cT1a RCC (≤4 cm) who underwent MRI-guided cryoablation. We excluded patients with genetic syndromes, bilateral RCC, recurrent RCC or benign lesions, those without pathologically proven RCC lesions and patients who underwent radiofrequency ablation or CT-guided cryoablation. For each patient, we collected the following: age, sex, lesion size, right- or left-sided, pathology, ablation zone tumor recurrence, development of new tumor in the kidney other than ablation zone, development of metastatic disease, patient alive or not, date and cause of death. We used the Kaplan and Meier product limit estimator to estimate the survival outcomes.

RESULTS

Twenty-nine patients (median age 70 years) met our inclusion criteria. Twenty-nine MRI-guided cryoablation procedures were performed for twenty-nine tumor lesions with a median size of 2.2 cm. A Clavien-Dindo grade III complication developed in one patient (3.4%). Clear cell RCC was the most reported histology (n = 19). The median follow up was 4.5 years. No tumor recurrence or metastatic disease developed in any of the patients. Two patients developed new renal lesions separate from the ablation zone. The 5- and 10-year OS were 72% and 55.6%, respectively. The 5- and 10-year DFS were 90.5% and the 5-year and 10-year LRFS, MFS and CSS were all 100%.

CONCLUSIONS

MRI-guided cryoablation is a safe treatment with a low complication rate. Long-term follow-up data revealed long-standing oncologic control.

Microwave ablation of 105 T1 renal tumors: technique efficacy with a mean follow-up of two years

BACKGROUND

Thermal ablation (TA) with radiofrequency (RFA) or cryoablation (CA) are established treatments for small renal masses (≤4 cm). Microwave ablation (MWA) has several potential benefits (decreased ablation time, less susceptibility to heat-sink, higher lesion temperatures than RFA) but is still considered experimental considering the available small-sample studies with short follow-up.

PURPOSE

To evaluate technique efficacy and complications of our initial experience of renal tumors treated using percutaneous MWA with a curative intent.

MATERIAL AND METHODS

A total of 105 renal tumors (in 93 patients) were treated between April 2014 and August 2017. MWA was performed percutaneously with computed tomography (CT) guidance under conscious sedation (n=82) or full anesthesia. Patients were followed with contrast-enhanced CT scans at six months and yearly thereafter for a minimum of five years. The mean follow-up time was 2.1 years. The percentage of tumors completely ablated in a single session (primary efficacy rate) and those successfully treated after repeat ablation (secondary efficacy rate) were recorded. Patient and tumor characteristics as well as complications were collected retrospectively.

RESULTS

The median patient age was 70 years and median tumor size was 25 mm. Primary efficacy rate was 96.2% (101/105 tumors). After including two residual tumors for a second ablation session, secondary efficacy was 97.1% (102/105). Periprocedural complications were found in 5.2% (5/95) sessions: four Clavien-Dindo I and one Clavien-Dindo IIIa. One postprocedural Clavien-Dindo II complication was found.

CONCLUSION

MWA has high efficacy rates and few complications compared to other TA methods at a mean follow-up of two years.

Percutaneous treatment of renal tumours

Image-guided ablation is an accepted treatment option in the management of renal cell carcinoma. Percutaneous renal ablation offers the possibility of minimally invasive treatment while attempting to preserve renal function. Over the past several years there have been advances in tools and techniques that have improved procedure safety and patient outcomes. This article provides an updated comprehensive review of percutaneous ablation in the management of renal cell carcinoma.

Machine Learning-Based Magnetic Resonance Radiomics Analysis for Predicting Low- and High-Grade Clear Cell Renal Cell Carcinoma

PURPOSE

To explore whether high- and low-grade clear cell renal cell carcinomas (ccRCC) can be distinguished using radiomics features extracted from magnetic resonance imaging.

METHODS

In this retrospective study, 154 patients with pathologically proven clear ccRCC underwent contrast-enhanced 3 T magnetic resonance imaging and were assigned to the development (n = 122) and test (n = 32) cohorts in a temporal-split setup. A total of 834 radiomics features were extracted from whole-tumor volumes using 3 sequences: T2-weighted imaging (T2WI), diffusion-weighted imaging, and contrast-enhanced T1-weighted imaging. A random forest regressor was used to extract important radiomics features that were subsequently used for model development using the random forest algorithm. Tumor size, apparent diffusion coefficient value, and percentage of tumor-to-renal parenchymal signal intensity drop in the tumors were recorded by 2 radiologists for quantitative analysis. The area under the receiver operating characteristic curve (AUC) was generated to predict ccRCC grade.

RESULTS

In the development cohort, the T2WI-based radiomics model demonstrated the highest performance (AUC, 0.82). The T2WI-based radiomics and radiologic feature hybrid model showed AUCs of 0.79 and 0.83, respectively. In the test cohort, the T2WI-based radiomics model achieved an AUC of 0.82. The range of AUCs of the hybrid model of T2WI-based radiomics and radiologic features was 0.73 to 0.80.

CONCLUSION

Magnetic resonance imaging-based classifier models using radiomics features and machine learning showed satisfactory diagnostic performance in distinguishing between high- and low-grade ccRCC, thereby serving as a helpful noninvasive tool for predicting ccRCC grade.

Effectiveness of Thermal Ablation for Renal Cell Carcinoma after Prior Partial Nephrectomy

Background

Repeat partial nephrectomy (PN) for tumors recurring in the ipsilateral kidney is associated with surgical complexity and a higher rate of complications.

Objective

To evaluate the local oncologic efficacy of thermal ablation (TA) for renal cell carcinoma (RCC) in the ipsilateral kidney following PN.

Design setting participation

We included patients who underwent ablation for renal tumors in the ipsilateral kidney after PN between January 2005 and December 2019. Demographics, tumor size, procedural details, complications, pathology, local oncologic outcomes, and survival outcomes are described.

Outcome measurements and statistical analysis

The procedural, pathologic, and oncologic outcomes are described. Survival rates were estimated using the Kaplan-Meier method.

Results and limitations

A total of 66 patients (46 male and 20 female) with a median age of 62 yr (interquartile range [IQR] 52-69) met our inclusion criteria. In these patients, 74 TA procedures were performed for 86 lesions (median tumor size 1.9 cm, IQR 1.6-2.5). Radiofrequency ablation and cryoablation accounted for 60 (81%) and 14 (19%) procedures, respectively. Three patients (3.7%) had Clavien-Dindo grade III complications. Of 65 lesion biopsies, 62 (95.5%) were diagnostic. The most common subtype was clear cell RCC (n = 37). The median imaging follow-up duration was 60 mo (IQR 43-88). Recurrence in the ablation zone occurred for four lesions (4.6%) at a median of 6.9 mo (IQR 6.4-10.7). The rates of overall, recurrence-free, and disease-free survival were 93.1%, 94.4%, and 65.6% at 5 yr, and 71.6%, 94.4%, and 60.1% at 10 yr, respectively. Limitations include the retrospective design and the lack of a control group.

Conclusions

TA is effective for the treatment of RCC in the ipsilateral kidney following PN.

Patient summary

Heat treatment to remove tumor tissue is an effective option for small kidney masses recurring after partial kidney removal for cancer. Long-term follow-up data revealed that this treatment resulted in low recurrence and complication rates.

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.

Percutaneous Renal Tumor Cryoablation Effect on Renal Function

Background: Percutaneous cryoablation (PCA) of renal tumors is a well-established alternative to partial nephrectomy, but the effects on renal function after the procedure are not well-documented. The purpose of this study was to evaluate renal function after computed tomography-guided PCA. Materials and Methods: A retrospective cohort study including 259 patients treated with PCA at Odense University Hospital, Denmark from January 1, 2015 to December 31, 2019. Both patients with malignant (96%) and benign tumors (4%) were included. Mean age of patients was 66.5 years (standard deviation [SD] = 10.9, range: 27-91) and 174 (67%) patients were men. Baseline estimated glomerular filtration rate (eGFR) was recorded at baseline and 12 months after cryoablation. Results: Mean tumor size was 27.5 mm (SD = 10.0) distributed in seven different histopathological types, mainly clear cell renal-cell carcinoma (RCC) (64%) and papillary RCC (22%). Mean eGFR at baseline was 73.7 mL/min/1.73 m2 (SD = 23.2) with a follow-up mean eGFR of 69.7 (SD = 23.7) (p < 0.0001). At baseline before intervention 190 patients (73%) had eGFR matching chronic kidney disease (CKD) groups 1 and 2 (normal to mild CKD), 64 patients (24%) matching CKD group 3 (average CKD), and 1% in groups 4 and 5. At 12-month follow-up, 171 patients (66%) had eGFR matching CKD groups 1 and 2, 77 patients (30%) matching CKD group 3 and 11 patients (4%) matching CKD groups 4 and 5. In patients with skewed renography who had PCA in the kidney with better excretion, eGFR at baseline was 64.7 and 61.2 at follow-up (p = 0.703). Conclusions: This study showed minimal decline in renal function 12 months after PCA, even for patients with reduced renal function. PCA is therefore considered a safe and relevant intervention.

Comparison of microwave ablation and partial nephrectomy for T1a small renal masses

OBJECTIVE

To compare the oncological and renal function outcomes of microwave ablation (MWA) compared to partial nephrectomy (PN) in two small renal mass (SRM) tumor size cohorts, <3 cm and 3-4 cm.

MATERIALS AND METHODS

This study included retrospective data from 2009 to 2015 and prospective data since 2015 from a single-institution database. Patient demographics, renal mass characteristics, and treatment outcomes were collected. Survival curves and hazard analysis were used to assess oncological outcomes. Changes in eGFR and CKD stage following surgery were used to assess renal function outcomes.

RESULTS

A total of 80 PN and 126 MWA patients were analyzed. Median age and Charlson Comorbidity Index (CCI) of MWA patients were greater than PN for each tumor size cohort. Cumulative progression free survival at 36-months was 91% for MWA and 90% for PN. Preoperative renal function was significantly lower in patients undergoing MWA for both tumor sizes, however there was no significant difference in the postoperative change in renal function between MWA and PN for tumors up to 4 cm.

CONCLUSIONS

Oncological outcomes and renal preservation were comparable between MWA and PN cohorts for SRMs <3cm and 3-4cm despite the MWA cohort being older and having more comorbidities. Our findings suggest that MWA can be used as a safe and effective alternative to PN for T1a renal tumors up to 4 cm.

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.

Microwave ablation of the T1a small renal mass: expanding beyond 3 cm

PURPOSE

To compare the oncological and renal function outcomes for patients receiving microwave ablation (MWA) in tumors < 3 and 3-4 cm.

METHODS

Retrospective analysis of a prospectively maintained database identified patients with < 3 or 3-4 cm renal cancers undergoing MWA. Radiographic follow-up occurred at approximately 6 months post-procedure and annually thereafter. Serum creatinine and estimated glomerular filtration rate (eGFR) were calculated before and 6-months post-MWA. Local recurrence-free survival (LRFS) was estimated using the Kaplan-Meier method. Tumor size was evaluated as a prognostic factor using Cox proportional-hazards regression. Predictors for change in eGFR and chronic kidney disease (CKD) stage were modeled using linear and ordinal logistic regression.

RESULTS

A total of 126 patients fit the inclusion criteria. Overall recurrences were 2/62 (3.2%) and 6/64 (9.4%) for < 3 versus 3-4 cm. Both recurrences in the < 3 cm group were local, 4/6 in the 3-4 cm group were local and 2/6 were metastatic without local progression. For < 3 versus 3-4 cm, cumulative LRFS at 36 months was 94.6% versus 91.4%. Tumor size was not a significant prognostic factor for LRFS. Renal function did not change significantly after MWA. Patient comorbidities and RENAL nephrometry score significantly affected change in CKD.

CONCLUSION

With comparable oncological outcomes, complication rates, and renal function preservation, MWA is a promising management strategy for renal masses of 3-4 cm in select patients. Our findings suggest that current AUA guidelines, which recommend thermal ablation for tumors < 3 cm, may need review to include T1a tumors for MWA, regardless of size.

The Judicious Use of Stereotactic Ablative Radiotherapy in the Primary Management of Localized Renal Cell Carcinoma

Localized renal cell carcinoma is primarily managed surgically, but this disease commonly presents in highly comorbid patients who are poor operative candidates. Less invasive techniques, such as cryoablation and radiofrequency ablation, are effective, but require percutaneous or laparoscopic access, while generally being limited to cT1a tumors without proximity to the renal pelvis or ureter. Active surveillance is another management option for small renal masses, but many patients desire treatment or are poor candidates for active surveillance. For poor surgical candidates, a growing body of evidence supports stereotactic ablative radiotherapy (SABR) as a safe and effective non-invasive treatment modality. For example, a recent multi-institution individual patient data meta-analysis of 190 patients managed with SABR estimated a 5.5% five-year cumulative incidence of local failure with one patient experiencing grade 4 toxicity, and no other grade ≥3 toxic events. Here, we discuss the recent developments in SABR for the management of localized renal cell carcinoma, highlighting key concepts of appropriate patient selection, treatment design, treatment delivery, and response assessment.

First UK patient cohort treated with stereotactic ablative radiotherapy for primary kidney cancer

Aims

Stereotactic ablative radiotherapy (SABR) for primary renal cell carcinoma (RCC) is a promising non-invasive ablative treatment option. A prospective interventional clinical trial published showed that treatment was feasible and well tolerated. We present the first single-institution UK cohort of patients with primary RCC receiving protocol-based SABR with prospective follow-up. We also present a protocol that could be used to facilitate more widespread use of the treatment.

Materials and methods

Nineteen biopsy-proven primary RCC patients were treated with either 42 Gy in three fractions on alternate days or 26 Gy in a single fraction based on predefined eligibility criteria using either Linear Accelerator or CyberKnife platform. Prospective toxicity data using CTCAE V4.0 and outcome data such as estimated glomerular filtration rate (eGFR) and tumour response using CT thorax, abdomen and pelvis (CT-TAP) were collected at 6 weeks, 3, 6, 12, 18 and 24 months post treatment.

Results

The 19 patients had a median age of 76 years (interquartile range [IQR] 64-82 years) and 47.4% were males, and they had a median tumour size of 4.5 cm (IQR 3.8-5.2 cm). Single and fractionated treatment was well tolerated and there were no significant acute side effects. The mean drop from baseline in eGFR at 6 months was 5.4 ml/min and that at 12 months was 8.7 ml/min. The overall local control rate at both 6 and 12 months was 94.4%. Overall survival at 6 and 12 months was 94.7% and 78.3%, respectively. After a median follow-up of 17 months, three patients experienced a Grade 3 toxicity, which was resolved with conservative management.

Conclusion

SABR for primary RCC is a safe and feasible treatment for medically unfit patients, which can be delivered in most UK cancer centres using standard Linear Accelerator as well as CyberKnife platforms.

Oncological and Peri-Operative Outcomes of Percutaneous Cryoablation of Renal Cell Carcinoma for Patients with Hereditary RCC Diseases-An Analysis of European Multi-Centre Prospective EuRECA Registry

This study aims to evaluate the safety, efficacy, and renal function preservation of percutaneous cryoablation (PCA) for small renal masses (SRMs) in inherited RCC syndromes. Patients with inherited T1N0M0 RCCs (<7 cm) undergoing PCA from 2015 to 2021 were identified from the European Registry for Renal Cryoablation (EuRECA). The primary outcome was local recurrence-free survival (LRFS). The secondary outcomes included technical success, peri-operative outcomes, and other oncological outcomes estimated using the Kaplan-Meier method. Simple proportions, chi-squared tests, and t-tests were used to analyse the peri-operative outcomes. A total of 68 sessions of PCA were performed in 53 patients with RCC and 85 tumours were followed-up for a mean duration of 30.4 months (SD ± 22.0). The overall technical success rate was 99%. The major post-operative complication rate was 1.7%. In total, 7.4% (2/27) of patients had >25% reduction in renal function. All oncological events were observed in VHL patients. Estimated 5-year LRFS, metastasis-free survival, cancer-specific survival, and overall survival were 96.0% (95% CI 75-99%), 96.4% (95% CI 77-99%), 90.9% (95% CI 51-99%), and 90.9% (95% CI 51-99%), respectively. PCA of RCCs for patients with hereditary RCC SRMs appears to be safe, offers low complication rates, preserves renal function, and achieves good oncological outcomes.

Endoscopic Ultrasound-Guided Local Ablative Therapies for the Treatment of Pancreatic Neuroendocrine Tumors and Cystic Lesions: A Review of the Current Literature

Since its emergence as a diagnostic modality in the 1980s, endoscopic ultrasound (EUS) has provided the clinician profound access to gastrointestinal organs to aid in the direct visualization, sampling, and subsequent identification of pancreatic pathology. In recent years, advancements in EUS as an interventional technique have promoted the use of local ablative therapies as a minimally invasive alternative to the surgical management of pancreatic neuroendocrine tumors (pNETs) and pancreatic cystic neoplasms (PCNs), especially for those deemed to be poor operative candidates. EUS-guided local therapies have demonstrated promising efficacy in addressing a spectrum of pancreatic neoplasms, while also balancing local adverse effects on healthy parenchyma. This article serves as a review of the current literature detailing the mechanisms, outcomes, complications, and limitations of EUS-guided local ablative therapies such as chemical ablation and radiofrequency ablation (RFA) for the treatment of pNETs and PCNs, as well as a discussion of future applications of EUS-guided techniques to address a broader scope of pancreatic pathology.

Radiation Therapy in the Treatment of Localized and Advanced Renal Cancer

Renal cell carcinoma (RCC) has historically been considered resistant to radiotherapy. However, advances in the field of radiation oncology have led to safe delivery of higher radiation doses through the use of stereotactic body radiotherapy (SBRT) that have shown significant activity against RCC. SBRT has now been shown to be a highly effective modality for management of localized RCC for nonsurgical candidates. Increasing evidence also points to a role for SBRT in the management of oligometastatic RCC as a means for not only providing palliation but prolonging time to progression and potentially improving survival.

The Prognostic Value of Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio for Small Renal Cell Carcinomas after Image-Guided Cryoablation or Radio-Frequency Ablation

There is a lack of cheap and effective biomarkers for the prediction of renal cancer outcomes post-image-guided ablation. This is a retrospective study of patients with localised small renal cell cancer (T1a or T1b) undergoing cryoablation or radiofrequency ablation (RFA) at our institution from 2003 to 2016. A total of 203 patients were included in the analysis. In the multivariable analysis, patients with raised neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) pre-operatively, post-operatively and peri-operatively are associated with significantly worsened cancer-specific survival, overall survival and metastasis-free survival. Furthermore, an increased PLR pre-operatively is also associated with increased odds of a larger than 25% drop in renal function post-operatively. In conclusion, NLR and PLR are effective prognostic factors in predicting oncological outcomes and peri-operative outcomes; however, larger external datasets should be used to validate the findings prior to clinical application.

Endourologic Procedures of the Upper Urinary Tract and the Effects on Intrarenal Pressure and Temperature

Introduction: Endourologic procedures, including ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL), are associated with an elevation in intrarenal pressures (IRPs) and irrigation temperatures. Recent research has focused on methods to reduce IRP and irrigation temperatures, with the ultimate goal to limit the consequences associated with these deviations. The purpose of our study is to provide a narrative review on the effects of endourologic procedures on pressure and temperature and provide recommendations to minimize these changes. Methods: A literature review was performed using PubMed. The search was limited to English human and nonhuman studies. Abstracts were reviewed for inclusion in our narrative review. Results: Human and animal models suggest that URS and PCNL are associated with peak IRPs above a "safe" threshold. Strategies to minimize pressures focus on minimizing irrigation flow into the upper tract and maximizing flow out of the system. High IRP has been associated with postoperative pain and infectious complications. Elevated irrigation temperatures are associated with high-power lasers during URS. Strategies to minimize irrigation temperatures focus on maximizing irrigation flow during laser activation and minimizing thermal energies associated with lithotripsy. Conclusions: Rises in pressure and irrigation temperatures associated with endourologic procedures are becoming increasingly recognized in the urologic community. Human studies examining "safe" thresholds for IRP and irrigation temperatures are limited. Temperature- and pressure-sensing technologies will aid in identifying the clinical consequences of elevated IRPs and irrigation temperatures, resulting in strategies to minimize them.

Outcomes of Radiofrequency Ablation for Solitary T1a Renal Cell Carcinoma: A 20-Year Tertiary Cancer Center Experience

BACKGROUND

The aim is to determine the long-term oncologic and survival outcomes of the radiofrequency ablation (RFA) of solitary de novo T1a renal cell carcinoma (RCC).

MATERIALS AND METHODS

We retrospectively reviewed our renal ablation registry and included only patients with new solitary, biopsy-proven T1a RCC (<4 cm) who underwent RFA from January 2001 through December 2020. We collected patient and tumor characteristics. Survival rates were estimated using the Kaplan-Meier method.

RESULTS

Of the 243 patients who met our inclusion criteria (160 male and 83 female, median age 68 years), 128 (52.6%) had another primary malignancy other than renal malignancy. Two-hundred forty-three RFA procedures were performed for 243 renal tumors of a median tumor size of 2.5 cm. The median follow-up period was 3.7 years. Most tumors (68.6%) were clear cell RCC. Ten patients (4.1%) experienced Clavien-Dindo Grade III complications. Seven patients(3.1%) developed recurrence at the ablation zone, and 11 (4.5%) developed recurrence elsewhere in the kidney. The 15-year local-recurrence- and disease-free survival were 96.5% and 88.6%, respectively. The 15-year metastasis-free survival and cancer-specific survival were 100%.

CONCLUSIONS

RFA is a highly effective modality for the management of T1a RCC, with low complication and recurrence rates. Long-term data revealed favorable oncologic and survival outcomes.

The Role of Focal Therapy and Active Surveillance for Small Renal Mass Therapy

Small and low-grade renal cell carcinomas have little potential for metastasis and disease-related mortality. As a consequence, the main problem remains the use of appropriately tailored treatment for each individual patient. Surgery still remains the gold standard, but many clinicians are questioning this approach and present the advantages of focal therapy. The choice of treatment regimen remains a matter of debate. This article summarizes the current treatment options in the management of small renal masses.

ACR Appropriateness Criteria® Post-Treatment Follow-up and Active Surveillance of Clinically Localized Renal Cell Carcinoma: 2021 Update

Renal cell carcinoma (RCC) accounts for most malignant renal tumors and is considered the most lethal of all urologic cancers. For follow-up of patients with treated or untreated RCC and those with neoplasms suspected to represent RCC, radiologic imaging is the most valuable component of surveillance, as most relapses and cases of disease progression are identified when patients are asymptomatic. Understanding the strengths and limitations of the various imaging modalities for the detection of disease, recurrence, or progression is essential when planning follow-up regimens. This document addresses the appropriate imaging examinations for asymptomatic patients who have been treated for RCC with radical or partial nephrectomy or ablative therapies. It also discusses the appropriate imaging examinations for asymptomatic patients with localized biopsy-proven or suspected RCC undergoing active surveillance. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Efficacy and Safety of Combined Embolization and Radiofrequency Ablation in Stage 1 Renal Cell Carcinomas

PURPOSE

 To retrospectively evaluate outcomes of a combined interventional approach to stage 1 (cT1cN0cM0) renal cell carcinomas (RCCs) by transarterial embolization (TAE) followed by percutaneous CT-guided radiofrequency ablation (RFA) in patients ineligible for surgery.

MATERIALS AND METHODS

 13 patients (9 male, 4 female, 69.6 ± 16.6 y/o) with 14 RCCs (largest diameter: 40.4 ± 6.7 mm, cT1a: 4, cT1b: 10) were treated by RFA a median of one day after TAE in a single center. Indications for minimally invasive interventional therapy were bilateral RCCs (n = 4), RCCs in a single kidney after nephrectomy (n = 3), increased surgical risk due to comorbidities (n = 4), and rejection of surgical therapy (n = 2). Technical success, effectiveness, safety, ablative margin, cancer-specific survival, overall survival, and tumor characteristics were analyzed.

RESULTS

 All RCCs were successfully ablated after embolization with a minimum ablative margin of 1.2 mm. The median follow-up was 27 (1-83) months. There was no residual or recurrent tumor in the ablation zone. No patient developed metastasis. Two minor and two major complications occurred. Four patients with severe comorbidities died during follow-up due to causes unrelated to therapy. The 1-year and 5-year overall survival was 74.1 % each. Cancer-specific survival was 100 % after 1 and 5 years. There was no significant decline in mean eGFR directly after therapy (p = 0.226). However, the mean eGFR declined from 62.2 ± 22.0 to 50.0 ± 27.8 ml/min during follow-up (p < 0.05).

CONCLUSION

 The combination of TAE and RFA provides an effective minimally invasive therapy to stage 1 RCCs in patients ineligible for surgery. The outcomes compare favorably with data from surgery.

KEY POINTS

  · Interventional treatment by TAE and ablation is a safe and effective alternative to surgery in stage 1 RCCs.. · Focal therapy of RCCs preserves renal function.. · A small ablative margin appears to be sufficient in the ablation of RCCs..

CITATION FORMAT

· Wessendorf J, König AM, Heers H et al. Efficacy and Safety of Combined Embolization and Radiofrequency Ablation in Stage 1 Renal Cell Carcinomas. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1770-4724.

Ablative therapies versus partial nephrectomy for small renal masses - A systematic review and meta-analysis

BACKGROUND

High quality studies and reviews on the management of small renal masses (SRM) are lacking. This review aims to compare oncological outcomes in patients undergoing ablative therapies (AT) or partial nephrectomy (PN) for T1a or T1b SRM.

MATERIAL AND METHODS

Medline, EMBASE, Cochrane CENTRAL and conference proceedings were searched on the 15th July 2020 for comparative studies respective to our research question. The ROBINS-I tool and the GRADE approach were used to assess any risk of biases and certainty of evidence in the included studies. The review is registered on PROSPERO.

RESULTS

1,748 records were retrieved. 32 observational studies and 1 RCT integrating 74,946 patients were included. Patients undergoing AT patients are significantly older than PN patients (MD 5.70, 95%CI 3.83-7.58). In T1a patients, AT patients have significantly worse overall survival (HR 1.64, 95%CI 1.39-1.95). Local recurrence-free survival is similar with PN in patients with longer than five-years follow up (HR 1.54, 95%CI 0.88-2.71). AT patients also have similar cancer-specific survival (CSS), metastasis-free survival, disease-free survival, significantly fewer post-operative complications (RR 0.72, 95%CI 0.55-0.94), and a smaller decline in estimated glomerular filtration rate post-operatively (MD: -7.42, 95%CI -13.1 to -1.70) compared to those undergoing PN. Evidence contradicts in T1b patients for oncological outcomes.

CONCLUSIONS

AT have similar long-term oncological durability; lower rates of complications and superior kidney function preservation compared to PN. Given the low quality of evidence, AT is a reasonable alternative to PN in frail and co-morbid patients. Long-term high-quality studies are needed to confirm the potential benefits of AT, especially in T1b patients.

PROSPERO REGISTRATION

CRD42020199099.

Long-term outcomes of image-guided ablation and laparoscopic partial nephrectomy for T1 renal cell carcinoma

OBJECTIVE

To compare long-term outcomes and peri-operative outcomes of image-guided ablation (IGA) and laparoscopic partial nephrectomy (LPN).

MATERIAL AND METHODS

This is a retrospective cohort study of localised RCC (T1a/bN0M0) patients undergoing cryoablation (CRYO), radio-frequency ablation (RFA), or LPN at our institution from 2003 to 2016. Oncological outcomes were compared using Cox regression and log-rank analysis. eGFR changes were compared using Kruskal-Wallis and Wilcoxon-rank tests.

RESULTS

A total of 296 (238 T1a, 58 T1b) consecutive patients were identified; 103, 100, and 93 patients underwent CRYO, RFA, and LPN, respectively. Median follow-up time was 75, 98, and 71 months, respectively. On univariate analysis, all oncological outcomes were comparable amongst CRYO, RFA, and LPN (p > 0.05). On multivariate analysis, T1a patients undergoing RFA had improved local recurrence-free survival (LRFS) (HR 0.002, 95% CI 0.00-0.11, p = 0.003) and metastasis-free survival (HR 0.002, 95% CI 0.00-0.52, p = 0.029) compared to LPN. In T1a and T1b patients combined, both CRYO (HR 0.07, 95% CI 0.01-0.73, p = 0.026) and RFA (HR 0.04, 95% CI 0.03-0.48, p = 0.011) had improved LRFS rates. Patients undergoing CRYO and RFA had a significantly smaller median decrease in eGFR post-operatively compared to LPN (T1a: p < 0.001; T1b: p = 0.047). Limitations include retrospective design and limited statistical power.

CONCLUSIONS

IGA is potentially as good as LPN in oncological durability. IGA preserves kidney function significantly better than LPN. More studies with larger sample size should be performed to establish IGA as a first-line treatment alongside LPN.

KEY POINTS

• Ablative therapies are alternatives to partial nephrectomy for managing small renal cell carcinomas. • This study reports long-term outcomes of image-guided ablation versus partial nephrectomy. • Ablative therapies have comparable oncological durability and better renal function preservation compared to partial nephrectomy.

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.

Multimodal image-guided ablation on management of renal cancer in Von-Hippel-Lindau syndrome patients from 2004 to 2021 at a specialist centre: A longitudinal observational study

OBJECTIVES

To analyse the safety, technical feasibility, long-term renal function and oncological outcome of multimodal technologies in image-guided ablation (IGA) for renal cancer in Von-Hippel-Lindau (VHL) patients, and to evaluate factors that may influence the outcome.

METHODS

Retrospective analysis of a prospective database of VHL patients who underwent IGA at a specialist centre. Patient's demographics, treatment energy, peri-operative outcome and oncological outcomes were recorded. Statistical analysis was performed to determine factors associated with complication and renal function reduction. The overall, 5 and 10-year cancer specific (CS), local recurrence-free (LRF) and metastasis-free (MF) survival rates were presented with Kaplan-Meier Curves.

RESULTS

From 2004 to 2021, 17 VHL patients (age 21-68.2) with a mean (±SD) RCC size of 2.06 ± 0.92 cm received IGA. Median (IQR) RCCs per patient was 3 (2-4) over the course of follow up. Fifty-four RCCs were treated using radiofrequency ablation (n = 11), cryoablation (n = 38) and irreversible electroporation (n = 8) in 50 sessions. Primary and overall technical success rate were 94.4% (51/54) and 98% (53/54). One CD-III complication with proximal ureteric injury. Five patients in seven treatment sessions experienced a >25% reduction of eGFR immediately post-IGA. All patients have preservation of renal function at a median follow-up of 79 (51-134) months. The 5 and 10-year CS, LRF and MF survival rates are 100%, 97.8% and 100%. Whilst, the 5 and 10-year overall survival rate are100% and 90%.

CONCLUSION

Multimodal IGA of de novo RCC for VHL patients is safe and has provided long term preservation of renal function and robust oncological durability.

Radiofrequency Ablation of Small Renal Masses

Although the incidence of localized renal cell carcinoma has increased in recent decades due to greater use of imaging, the treatment has shifted to less invasive, nephron-sparing approaches. Radiofrequency ablation (RFA) is one accepted treatment modality for patients with small renal masses, and it has the advantage of being minimally invasive and highly nephron sparing, with the additional benefits of reduced blood loss and complication rates. We describe our experience with RFA with an accompanying instructional video outlining the procedure's key components.

Computed Tomography-Guided Percutaneous Microwave Ablation for Renal Cell Carcinoma: Impact of Tumor Size on the Progression Survival Rates

The aim of the present study was to evaluate the safety and efficacy of computed tomography (CT)-guided percutaneous microwave ablation (MWA) of renal cell carcinoma (RCC) along with identifying prognostic factors affecting the progression survival rate. Institutional database retrospective research identified 69 patients with a biopsy proven solitary T1a (82.6%) or TIb (17.4%) RCC who have underwent percutaneous CT-guided MWA. Kaplan–Meier survival estimates for events were graphed and Cox regression analysis was conducted. Mean patient age was 70.4 ± 11.5 years. Mean size of the lesions was 3 ± 1.3 cm. Mean follow up time was 35.6 months (SD = 21.1). The mean progression free survival time from last ablation was 84.2 months. For T1a tumors, the cumulative progression free survival rate for 1, 6, 12 and 36 months were 100% (SE = 0%), 91.2% (SE = 3.7%), 91.2% (SE = 3.7%) and 87.5% (SE = 4.4%); the recurrence free survival rate for T1a RCC was 94.9%. For T1b tumors, the cumulative progression free survival rate for 1, 6, 12 and 36 months were 100% (SE = 0%), 63.6% (SE = 14.5%), 63.6% (SE = 14.5%) and 63.6% (SE = 14.5%). Grade 1 complications were recorded in 5 (7.2%) patients. Significantly greater hazard for progression was found in cases with a tumor size > 4 cm (HR = 9.09, p = 0.048). No statistically important difference regarding tumor progression was recorded between T1a tumors with a diameter ≤3 cm and >3 cm. In summary, the results of the present study show that CT guided percutaneous MWA is an effective technique for treatment of T1a renal cell carcinomas, irrespective of tumor size. T1b tumors were associated with higher progression rates.

Postoperative outcomes of elderly patients undergoing partial nephrectomy

To describe clinical outcomes of patients aged 75 years and above after partial nephrectomy (PN), and to assess independent factors of postoperative complications. We retrospectively reviewed information from our multi-institutional database. Every patient over 75 years old who underwent a PN between 2003 and 2016 was included. Peri-operative and follow up data were collected. Multivariate logistic regression was performed to determine independent predictive factors of postoperative complications. We reviewed 191 procedures including 69 (40%) open-surgery, and 122 (60%) laparoscopic procedures, of which 105 were robot-assisted. Median follow-up was 25 months. The mean age was 78 [75–88]. The American Society of Anesthesiologist’s score was 1, 2, 3 and 4 in 10.5%, 60%, 29% and 0.5% of patients respectively. The mean tumor size was 4.6 cm. Indication of PN was elective in 122 (65%) patients and imperative in 52 patients (28%). The median length of surgery was 150(± 60) minutes, and the median estimated blood loss 200 ml. The mean glomerular filtration rate was 71.5 ml/minute preoperatively, and 62 ml/min three months after surgery. The severe complications (Clavien III-V) rate was 6.2%. On multivariate analysis, the robotic-assisted procedure was an independent protective factor of medical postoperative complications (Odds Ration (OR) = 0.31 [0.12–0.80], p = 0.01). It was adjusted for age and RENAL score, robotic-assisted surgery (OR = 0.22 [0.06–0.79], p = 0.02), and tumor size (OR = 1.13 [1.02–1.26], p = 0.01), but the patients age did not forecast surgical complications. Partial nephrectomy can be performed safely in elderly patients with an acceptable morbidity, and should be considered as a viable treatment option. Robotic assistance is an independent protective factor of postoperative complications.

Association of Clear Cell Likelihood Score on MRI and Growth Kinetics of Small Solid Renal Masses on Active Surveillance

Background: The lack of validated imaging markers to characterize biologic aggressiveness of small renal masses (SRMs; cT1a, ≤4 cm) hinders medical decision making amongst available initial management strategies. Objective: To explore the association of the clear cell likelihood score (ccLS) on MRI with growth rates and progression of SRMs. Methods: This retrospective study included consecutive SRMs assigned a ccLS on clinical MRI examinations performed between June 2016 and November 2019 at an academic tertiary-care medical center or its affiliated safety net hospital system. The ccLS scores the likelihood that the SRM represents clear cell renal cell carcinoma (ccRCC) from 1 (very unlikely) to 5 (very likely). The ccLS was extracted from clinical reports. Tumor size measurements were extracted from available prior and follow-up cross-sectional imaging examinations, through June 2020. Serial tumor size measurements were fit to linear and exponential growth curves. Estimated growth rates were grouped by the assigned ccLS. Tumor progression was defined by development of large size (>4 cm in at least two measurements) and/or rapid growth (doubling of volume within 1 year). Differences among ccLS groups were evaluated using Kruskal-Wallis tests. Correlation between ccLS and growth rate were evaluated by Spearman correlation (ρ). Results: Growth rates of 386 SRMs (100 ccLS1-2, 75 ccLS3, and 211 ccLS4-5) from 339 patients (median age 65 years; 198 men, 141 women) were analyzed. Median follow-up was 1.16 years. The ccLS was correlated with growth rates by size (ρ=0.19, p<.001; ccLS4-5: 9%/year, ccLS1-2: 5%/year, p<.001) and by volume (ρ=0.136, p=.008; ccLS4-5: 29%/year, ccLS1-2: 16%/year, p<.001). Disease progression (observed in 49 SRMs) was not significantly associated with ccLS group (p=.61). Two patients (0.6%) developed metastases during active surveillance (AS): one ccLS1 that was a type 2 papillary renal cell carcinoma and one ccLS4 that was ccRCC. Conclusions: Growth is associated with ccLS in SRMs, with higher ccLS correlating with faster growth. Clinical Impact: The non-invasive clear cell likelihood score (ccLS), derived from MRI, correlates with growth rate of SRMs and may help guide personalized management. SRMs with lower ccLS may be considered for AS, whereas SRMs with higher ccLS may warrant earlier intervention.

Local anesthesia for percutaneous US/CT-guided bipolar radiofrequency ablation of small renal masses: A safe and feasible alternative

PURPOSE

This study is to evaluate the safety and feasibility of local anesthesia (LA) for percutaneous ultrasound/computed tomography (US/CT)-guided bipolar radiofrequency ablation (RFA) for small renal masses (SRMs) by comparing the LA with general anesthesia.

MATERIALS AND METHODS

A retrospective review was carried out between January 2018 to June 2020, 102 patients with SRMs were treated with US/CT-guided bipolar RFA. General anesthesia (GA) was performed in 42 and LA was performed in 60 patients. Demographics, tumor characteristics, peri-procedural data, pathologic and follow-up outcomes were analyzed. The factors associated with pain were also identified.

RESULTS

There was no significant difference in demographics and tumor characteristics between the LA and GA group. A statistically significant difference was observed in terms of procedural time (P = 0.010) and hospital stays (P < 0.001). The maximum perceived pain in LA group comprised 60.0% (36 of 60) mild, 40.0% (24 of 60) moderate. The anxiety in LA group comprised 65.0% (39 of 60) mild, 33.3% (20 of 60) moderate, 1.7% (1 of 60) severe. On multivariate analysis, tumor diameter was a significant predictor for pain in RFA procedure (OR 1.560, 95% CI 1.233-1.974, P < 0.001). All patients were followed up for a median (range) of 12 (2-24) months. Local recurrence occurred in 8.3% (5 of 60) of the LA group and in 7.1% (3 of 42) in GA group (P = 1.000).

CONCLUSION

Percutaneous bipolar RFA of SRMs using CT and ultrasound guidance under LA can be an effective and tolerable method for patients who are unfit for surgery and provide satisfactory oncologic control.

Long term follow-up results of ablation treatment for patients with small renal mass

OBJECTIVE

The aim of this study is to evaluate the outcome of ablation therapy in our clinic for the treatment of patients with a small renal mass Materials and Methods: We retrospectively evaluated the technic and follow-up data of 30 patients with 36 tumours who underwent Radiofrequency Ablation (RFA) and Microwave Ablation (MWA) in our clinic. Demographic data, ablation type, tumour characteristics, peroperative and postoperative complications and treatment success of the patients were evaluated.

RESULTS

A total of 36 tumours who underwent ablation treatments, 23 were treated with RFA, 13 with MWA. The mean tumour size was 28.9 ± 6.92 mm in RFA and 29.3 ± 7.70 mm in MWA. The mean follow-up period was 49.6 ± 24.7 months in patients with RFA and mean follow-up was 16 ± 8.05 months in MWA treatments. The overall success in MWA administration was calculated as 76.9%, while the overall success in RFA was 80%.

CONCLUSION

Long-term oncologic efficacy of RFA appears to be successful in the treatment of T1a renal carcinomas. Further studies can be conducted to elucidate the influence of MWA on long-term oncological outcomes.

Iatrogenic ureteric stricture post image guided renal cryoablation in a patient with von hippel-lindau syndrome

A 53-year-old lady is known to have Von Hippel-Lindau syndrome with a long history of previous renal cell carcinomas (RCCs) in both kidneys. She was treated by partial nephrectomy for a right peripheral RCC and subsequently image guided radiofrequency ablation (RFA) of a left central RCC. She developed another de novo RCC adjacent to the right pelvic-ureteric junction (PUJ) 4 years after the initial RFA. Due to the close proximity to the PUJ and visibility of an ice ball with cryoablation (CRYO), the consensus from the MDT was that CRYO would be safer than RFA and she subsequently underwent percutaneous image guided CRYO to treat the small de novo RCC. Unfortunately, during the 1-month imaging follow up, she developed moderate hydronephrosis and a ureteric stricture needing long-term ureteric stent management. This case highlights the risk of ureteric injury caused by the thermal effect of the ice ball during image guided renal CRYO. Therefore, it is vital that all interventional radiologists adopt various manoeuvres to protect the ureter from the ice ball during CRYO in order to avoid the development of latent ureteric stricture.

The role of imaging in the management of renal masses

The wide availability of cross-sectional imaging is responsible for the increased detection of small, usually asymptomatic renal masses. More than 50 % of renal cell carcinomas (RCCs) represent incidental findings on noninvasive imaging. Multimodality imaging, including conventional US, contrast-enhanced US (CEUS), CT and multiparametric MRI (mpMRI) is pivotal in diagnosing and characterizing a renal mass, but also provides information regarding its prognosis, therapeutic management, and follow-up. In this review, imaging data for renal masses that urologists need for accurate treatment planning will be discussed. The role of US, CEUS, CT and mpMRI in the detection and characterization of renal masses, RCC staging and follow-up of surgically treated or untreated localized RCC will be presented. The role of percutaneous image-guided ablation in the management of RCC will be also reviewed.

Percutaneous radiofrequency for the treatment of small renal masses: Analysis of outcomes and complications after 10 years of experience

INTRODUCTION AND OBJECTIVE

The management of renal tumors ≤ 4 cm in elderly population or patients with comorbidities is a challenge, for which ablative therapies are an interesting alternative. The objective is to evaluate in our center the role of percutaneous radiofrequency in the treatment of small renal masses, the associated complications and the results obtained.

MATERIAL AND METHODS

Retrospective evaluation of the radiofrequency treatments carried out between April 2010 and April 2020 in our center. Demographic data, associated comorbidities, tumor characteristics, complications and oncological and functional outcomes were reviewed.

RESULTS

Fifty-seven tumors were treated in 53 patients. Mean follow-up of 48.2 months. The percentage of complete ablations obtained was of 89.5%. There were 19.3% of complications. According to Clavien-Dindo and SIR classification systems, 3.5% and 5.3% were major complications. A statistically significant association was found between the initial result of ablation and age (p = 0.047), RENAL-m (p = 0.044), the presence of cystic component (p = 0.049) and tumor size (p = 0.01). The cut-off point for size was established at 25 mm (p = 0.012). In multivariate analysis, only size remained as a predictor of initial ablation result (p = 0.01; OR 1.183; CI 95% 1.041-1.345). Cancer-specific survival and 5-year recurrence-free survival were 98.1% and 89.5%, respectively. A mean decrease of MDRD-4 of 6.59 mL/min (p = 0.005) was observed in the first six months after RFA.

CONCLUSIONS

Given the excellent oncological and functional results demonstrated, ultrasound-guided percutaneous radiofrequency ablation is an effective and safe treatment for small renal masses in selected patients.

Outcomes of Percutaneous Thermal Ablation for Biopsy-Proven T1a Renal Cell Carcinoma in Patients With Other Primary Malignancies

OBJECTIVE. The purpose of this article is to investigate the oncologic effectiveness and survival outcomes of percutaneous image-guided thermal ablation for clinical T1a renal cell carcinoma (RCC) in patients with other primary nonrenal malignancies. MATERIALS AND METHODS. We reviewed records of patients with histologically proven T1a RCC (< 4.0 cm) treated with thermal ablation over a period of 10 years between January 2005 and December 2014. We recorded past or current history of primary malignancy other than RCC, status of the primary malignancy, tumor histology (in remission or under therapy), and whether patient was currently alive or not, and if not, the date and reason of death. Three cohorts were studied: patients with RCC only (group A), patients with RCC and other primary malignancy in remission (group B), and patients with RCC and other primary malignancy under treatment (group C). The Kaplan-Meier product-limit estimator was used to estimate the survival rates. RESULTS. One hundred nine patients met the inclusion criteria (109 lesions, 110 ablation procedures). There were 46, 45, and 18 patients in the A, B, and C groups, respectively. The 5-year survival was 87%, 63%, and 40% for groups A, B, and C, respectively. The local recurrence-free survival for the whole sample was 95% at 3, 5, and 10 years. The disease-free survival was 96%, 93%, and 91% at 3, 5, and 10 years. Although a significant difference is noted between the three cohorts in overall survival (p = .02); for RCC, there were no significance differences in the local recurrence-free, disease-free, metastasis-free, and cancer-specific survivals. In addition, there was no difference in outcomes for patients in group B (in remission) when compared with those in group C (under treatment). CONCLUSION. Thermal ablation is an effective and safe modality of treatment of T1a RCC in patients with other primary malignancies that are in remission or under treatment.

Irreversible electroporation (IRE) in renal cell carcinoma (RCC): a mid-term clinical experience

Objectives

To evaluate the safety and efficacy of CT-guided IRE of clinical T1a (cT1a) renal tumours close to vital structures and to assess factors that may influence the technical success and early oncological durability.

Methods

CT-guided IRE (2015–2020) was prospectively evaluated. Patients’ demographics, technical details/success, Clavien-Dindo (CD) classification of complications (I–V) and oncological outcome were collated. Statistical analysis was performed to determine variables associated with complications. The overall 2- and 3-year cancer-specific (CS), local recurrence-free (LRF) and metastasis-free (MF) survival rates are presented using the Kaplan-Meier curves.

Results

Thirty cT1a RCCs (biopsy-proven/known VHL disease) in 26 patients (age 32–81 years) were treated with IRE. The mean tumour size was 2.5 cm and the median follow-up was 37 months. The primary technical success rate was 73.3%, where 22 RCCs were completely IRE ablated. Seven residual diseases were successfully ablated with cryoablation, achieving an overall technical success rate of 97%. One patient did not have repeat treatment as he died from unexpected stroke at 4-month post-IRE. One patient had CD-III complication with a proximal ureteric injury. Five patients developed > 25% reduction of eGFR immediately post-IRE. All patients have preservation of renal function without the requirement for renal dialysis. The overall 2- and 3-year CS, LRF and MF survival rates are 89%, 96%, 91% and 87%.

Conclusion

CT-guided IRE in cT1a RCC is safe with acceptable complications. The primary technical success rate was suboptimal due to the early operator’s learning curve, and long-term follow-up is required to validate the IRE oncological durability.

Key Points

• Irreversible electroporation should only be considered when surgery or image-guided thermal ablation is not an option for small renal cancer.

• This non-thermal technique is safe in the treatment of small renal cancer and the primary technical success rate was 73.3%.

• This can be used when renal cancer is close to important structure.

Safety and oncological outcome following radiofrequency ablation of small renal masses in a single center

OBJECTIVE

To evaluate the safety and efficacy of percutaneous CT-guided radiofrequency ablation (RFA) for small renal masses (SRMs) at a large single-institution center during a period of 12 years.

MATERIALS AND METHODS

A total of 118 patients underwent RFA for SRM between July 2006 and July 2018 at our institution. We included demographic information, comorbidity, procedural details, and oncological outcome in the analysis. Survival analysis was performed using competing risk.

RESULTS

87 males and 31 females with median age 66 years underwent RFA. Median tumor size was 23 mm. Tumor biopsy was performed in 94% of cases, of which 56% were confirmed renal cell carcinoma (RCCs). Twenty-eight patients had benign tumors or underwent treatment for recurrence of prior RCC. Median follow-up of 5 years. Median Charlson Comorbidity Index was 5. Major complications occurred in 1.7%. No change in kidney function was observed. The initial treatment response was 98%. Among patients treated for newly diagnosed radiological suspected RCC without Von Hippel-Lindau or benign biopsy (90 pts), the cumulative incidence of radiological recurrence after 5 and 10 years was 6.6% (95% CI: 0.8-12%) and 16% (95% CI: 4.2-28%), respectively. Three patients died of RCC during follow-up. The cumulative incidence of kidney cancer death was 4.5% (95% CI: 4.3-13%) after 10 years. The incidence of other-cause mortality was 50% (95% CI: 34-67%).

CONCLUSION

CT-guided RFA is a safe and effective treatment option for patients unsuitable for surgery. RFA is a good alternative to partial or radical nephrectomy for SRMs, although randomized trials comparing surgery to minimally invasive thermal ablation techniques are missing.

[Long-term follow-up of renal cell carcinomas T1a treated by percutaneous radiofrequency]

OBJECTIVE

To evaluate the long-term oncological and functional results of the ablative treatment of T1a kidney malignancies by percutaneous radiofrequency (RF).

MATERIALS AND METHODS

Monocentric retrospective study including all patients treated for renal cell carcinoma (RCC) T1a by radiofrequency, in our center, from 2005 to 2009. All patients had a tumor biopsy before treatment. The primary endpoint was local recurrence. A total of 44 RCCs in 41 consecutive patients were treated (1 patient had 3 synchronous tumors and 1 patient had 2 tumors). There were 26 clear cell RCCs, 13 papillary RCCs and 5 chromophobe RCCs. The median age at diagnosis was 70 years [48-82]. The median American Society of Anesthesiologists (ASA) score was 2 [1-3] and the median glomerular filtration rate (GFR) was 64mL/min [26-109]. Furhman grade was defined for 39 tumors (Clear cell RCC and papillary RCC), of which 82% were grade 1-2. The median tumor size was 20mm [11-40], and the median RENAL score was 4 [4-6]. Complications were assessed according to the Clavien-Dindo classification. Overall survival, recurrence-free survival and metastasis-free survival were calculated using the Kaplan-Meier method.

RESULTS

Median follow-up was 90.5 months [17.8-145.3]. Three (7%) local recurrences were reported within a median of 26 months [12-93]. All were treated by a 2nd RF. The overall 10-year survival was 70% (95% CI [56-85]). The 10-year recurrence-free survival was 72% (95% CI [57-88]). The 10-year metastasis-free survival was 87% (95% CI [74-97]). The median GFR on the date of the last news was 51mL/min [16-98] (P=0.05). Post-RFA complications consisted in 5 (11.3%) Clavien-Dindo 1-2 complications. No high grade (Clavien ≥3).

CONCLUSION

Percutaneous radiofrequency for RCC T1a is an alternative. It appears to be safe with low morbidity, satisfaying long-term oncological and functional results, but a risk of reprocessing of 7%.

LEVEL OF EVIDENCE

3.

Rapid Segmentation of Renal Tumours to Calculate Volume Using 3D Interpolation

Small renal masses are commonly diagnosed with modern medical imaging. Renal tumour volume has been explored as a prognostic tool to help decide when intervention is needed and appears to provide additional prognostic information for smaller tumours compared with tumour diameter. However, the current method of calculating tumour volume in clinical practice uses the ellipsoid equation (π/6 × length × width × height) which is an oversimplified approach. Some research groups trace the contour of the tumour in every image slice which is impractical for clinical use. In this study, we demonstrate a method of using 3D segmentation software and the 3D interpolation method to rapidly calculate renal tumour volume in under a minute. Using this method in 27 patients that underwent radical or partial nephrectomy, we found a 10.07% mean absolute difference compared with the traditional ellipsoid method. Our segmentation volume was closer to the calculated histopathological tumour volume than the traditional method (p = 0.03) with higher Lin's concordance correlation coefficient (0.79 vs 0.72). 3D segmentation has many uses related to 3D printing and modelling and is becoming increasingly common. Calculation of tumour volume is one additional benefit it provides. Further studies on the association between segmented tumour volume and prognosis are needed.

Assessment of the effectiveness of radiofrequency ablation as a technique for destroying small renal tumors in patients older than 70

Introduction

During the past few decades, the percentage of older people in the population has been steadily growing due to the tendency of extended life expectancy. The efficacy of radiofrequency ablation (RFA) and tumor enucleoresection (TE) in the treatment of selected older patients with renal cell carcinoma (RCC) T1aN0M0 sized ≤4.0 cm has been a popular topic in many recent studies.

The aim of this study was to access the effectiveness of radiofrequency ablation in patients older than 70 with T1aN0M0 RCC.

Material and methods

A total of 86 patients aged 70–84 with histologically confirmed solitary kidney tumors T1aN0M0 who underwent RFA (n = 39) and TE (n = 47) were been included in this study. The patients were assigned to groups based on the impact of their comorbidities. Rockwood’s Clinical Frailty Scale Score (FS) and Charlson Comorbidity Index score (CCI) were used to separate fit from unfit older patients. The RFA group was characterized by an FS and CCI of 4–5 while the TE group had scores of ≤3. Five-year disease-specific survival (DSS), 5-yrs overall survival (OS) and relapse-free survival (RFS) were considered as criteria of treatment.

Results

The 5-yr DSS in the RFA group was 97.4% vs. 95.7% in the TE group (p >0.05), while 5-yr OS was 74.4% vs. 80.9% (p <0.05) and RFS – 94.9% vs. 93.6% (p >0.05) respectively. Functioning of the operated kidneys did not deteriorate at the 6^th and 12^th month after RFA/TE as assessed by radioisotope renography.

Conclusions

In patients over 70 years of age, percutaneous RFA might be considered as an effective option for the successful treatment of T1aN0M0 RCC, as it preserves the functioning of the treated kidney and has oncological outcomes similar to TE.

Percutaneous thermoablation of small renal masses (T1a) in surgical candidate patients: oncologic outcomes

OBJECTIVE

To evaluate the local tumour progression-free survival (LTPFS), metastasis-free survival (MFS), cancer-specific survival (CSS) and overall survival (OS) of healthy surgical candidates who underwent percutaneous thermoablation (TA) as a first-line therapy for small renal masses (T1a).

METHODS

The institutional review board approved this bi-institutional retrospective study of 85 consecutive surgical candidates with 97 biopsy-proven malignant renal masses (T1a) treated with percutaneous TA from 2008 to 2016. The LTPFS, MFS, CSS and OS rates were calculated using the Kaplan-Meier method. Descriptive analysis was also performed.

RESULTS

The median tumour size was 2.3 cm (range, 0.7-3.9 cm). The minimal and mean follow-up periods were 24 and 56 months, respectively. Local recurrence was detected in four patients (4.7%) at 8.5, 13.8, 58.0 and 64.0 months of follow-up and retreated successfully with percutaneous TA. No patient developed metastatic renal cell carcinoma, and none died due to renal oncologic complications. One patient died of heart attack. The 5-year LTPFS, OS, MFS and CSS rates were 93.0%, 98.4%, 100% and 100%, respectively. Only two patients (2.3%) had major complications (Clavien-Dindo grade > II), including ureteropelvic junction stenosis and urinary obstruction due to ureteral blood clots.

CONCLUSIONS

Our study demonstrates that percutaneous TA is a feasible and effective first-line therapy for healthy surgical candidates with small renal masses (T1a). The 5-year LTPFS, OS, CSS and MFS rates were 93.0%, 98.4%, 100% and 100%, respectively, with a major complication rate of only 2.3%.

KEY POINTS

• Image-guided percutaneous thermoablation of small renal malignancies was effective in 95.3% of the healthy surgical candidates. • Major complications were detected in 2.3% of the patients. • The local tumour progression-free survival rate was 97.6% and 93.0% at 3 and 5 years, respectively.

Risk Factors of Ureteral Stenosis After Percutaneous Microwave Ablation of Renal Tumor, a Single-Center Experience

Background

Ureteral stenosis after percutaneous microwave ablation (MWA) of renal tumor is a rare but severe complication, and its risk factors are not apparent.

Purpose

This study aimed to investigate the risk factors for stenosis of ureter after MWA treatment of the renal tumor that is a rare complication.

Materials and Methods

Data of 211 patients who underwent MWA for the treatment of renal tumor were retrospectively analyzed from September 2006 to August 2019. Demographic characteristics, clinical features, ablation parameters, and outcomes were analyzed to find out the potential risk factors of this complication. P < 0.05 is considered significant.

Results

Six of 211 patients developed ureter stenosis, and the rate of this complication is 2.84%. The median time of emergence of hydronephrosis was 226 (range, 3-390) days. Univariate analysis shows the distance between ureter and tumor (P = 0.225) or ablation zone (P = 0.089) is not related to this complication. Postoperative urine routine (red blood cell, P = 0.001; white blood cell, P = 0.035) and R.E.N.A.L. score (P < 0.001) is related to this complication. But after multivariate logistic analysis, only R.E.N.A.L. score (P = 0.004) is associated with this complication. The location and growth pattern of tumor and the energy of ablation were not related to this complication independently.

Conclusion

The stenosis of the ureter after MWA of renal tumor is not associated with the tumor size, location, or the distance between the ureter and tumor and ablation site independently. But R.E.N.A.L. score is associated with ureter stenosis after MWA for the treatment of renal tumor, which combines the information of location, depth, and size of tumor. Preoperative evaluation of the tumor is necessary for avoiding ureter stenosis. Further studies should focus on these risk factors of this complication.