Radiofrequency ablation of renal cell carcinoma: part 1, Indications, results, and role in patient management over a 6-year period and ablation of 100 tumors

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Safety and Technical Feasibility of Percutaneous Renal Cryoablation of Central Tumors without Pyeloperfusion

PURPOSE

To assess the safety and technical success of percutaneous cryoablation (PCA) without pyeloperfusion in 94 patients with central renal tumors.

MATERIALS AND METHODS

A retrospective review of all central renal tumors treated by PCA without pyeloperfusion was performed. Central tumors were defined as those involving the renal sinus fat on preprocedural cross-sectional imaging. Patient demographics and baseline tumor characteristics were recorded. The details of the PCA procedure, primary and secondary technical success, rates of local recurrence, adverse events (AEs), cancer-specific survival (CSS), and overall survival (OS) were compiled.

RESULTS

Ninety-four patients (48 females [51%]; mean age, 68.2 years [range, 38-87 years]) with 94 central renal tumors were included. The mean maximal tumor diameter and mean RENAL nephrometry score were 37 mm (range, 15-67 mm) and 8 (range, 4-11), respectively. Primary technical success was achieved in 94% (n = 88) of procedures. Of the patients who did not achieve primary technical success, 3 underwent successful repeat PCA (secondary technical success, 97%; n = 91/94). The other 3 patients were surveilled for residual disease. Twenty-four patients (26%) required hydrodissection during PCA. Six patients (6%) experienced major AEs after PCA including hemorrhage requiring embolization (n = 3), hemorrhage requiring transfusions with admission (n = 2), and perinephric abscess necessitating drain placement (n = 1). Twenty-two patients (23%) experienced minor AEs. Nine patients (10%) experienced local recurrence during the follow-up period. OS was 94% (n = 88/94), whereas CSS was 98% (n = 92/94) during the study follow-up period (mean, 16 months [range, 1-102 months]).

CONCLUSIONS

PCA of central renal tumors appears to be safe with high rates of technical success, even without the use of pyeloperfusion.

Ablative Treatments for Small Renal Masses and Management of Recurrences: A Comprehensive Review

This review focuses on ablative techniques for small renal masses (SRMs), including radiofrequency ablation (RFA), cryoablation (CA), microwave ablation (MWA), and irreversible electroporation (IRE), and discusses recurrence management. Through an extensive literature review, we outline the procedures, outcomes, and follow-up strategies associated with each ablative method. The review provides a detailed examination of these techniques-RFA, CA, MWA, and IRE-elucidating their respective outcomes. Recurrence rates vary among them, with RFA and CA showing comparable rates, MWA demonstrating favorable short-term results, and IRE exhibiting promise in experimental stages. For managing recurrences, various strategies are considered, including active surveillance, re-ablation, or salvage surgery. Surveillance is preferred post-RFA and post-CA, due to slow SRM growth, while re-ablation, particularly with RFA and CA, is deemed feasible without additional complications. Salvage surgery emerges as a viable option for larger or resistant tumors. While ablative techniques offer short-term results comparable to surgery, further research is essential to understand their long-term effects fully. Decisions concerning recurrence management should consider individual and tumor-specific factors. Imaging, notably contrast-enhanced ultrasounds, plays a pivotal role in assessing treatment success, emphasizing the necessity of a multidisciplinary approach for optimal outcomes. The lack of randomized trials highlights the need for further research.

Management of Renal Cell Carcinoma With Supradiaphragmatic Inferior Vena Cava Thrombus Diagnosed During Acute COVID-19 Infection

Renal cell carcinoma (RCC) tends to undergo intravascular tumor growth along the renal vein, forming tumor thrombi that may extend into the inferior vena cava (IVC) or even the right atrium (Level IV). Managing such cases requires a multidisciplinary approach, especially in patients with acute coronavirus disease 2019 (COVID-19) infection, who face increased risks from surgical interventions. We present a case of RCC with Level IV thrombus and concurrent COVID-19 managed with systemic therapy. We also summarize current literature on treating RCC with IVC thrombus and COVID-19's impact on prognosis. The patient was a 70-year-old female with incidental detection of a 9-cm right heterogeneous renal mass with a supradiaphragmatic tumor thrombus during COVID-19 infection. Due to ongoing pulmonary symptoms, systemic therapy with a combination of ipilimumab and nivolumab was initiated. After an excellent initial response, the patient continued systemic therapy, maintaining a necrotic response in the renal mass and tumor thrombus. The patient continues to tolerate systemic therapy well. We report a rare case of RCC with Level IV tumor thrombus and synchronous acute COVID-19 infection. Our report depicts successful management utilizing systemic therapy with a combination of ipilimumab and nivolumab. The management of such cases necessitates a comprehensive, multidisciplinary approach, considering the risks associated with surgery in the context of recent COVID-19 infection. The case presentation and ensuing literature discussion of the dynamic landscape of RCC management highlights the need for more research to improve treatment plans and guide clinicians in handling such complex situations.

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.

Efficacy and safety of MWA versus RFA and CA for renal tumors: A systematic review and meta-analysis of comparison studies

PURPOSE

Thermal ablation procedures represent an alternative treatment option for patients with T1a renal tumors. Radiofrequency ablation (RFA) and cryoablation (CA) are the most used and studied techniques, while microwave ablation (MWA) has progressively emerged in recent years. Our aim was to assess the effectiveness and safety of MWA in comparison to RFA and CA for the treatment of primary renal tumors.

METHOD

Pubmed, CENTRAL, Web of Science and Scopus were searched until March 2023 to identify studies aimed at comparing the efficacy and safety of MWA with those of RFA and CA for the treatment of patients with primary renal tumors. We compared MWA and RFA/CA primary technique efficacy, local recurrences, overall and cancer-specific survival, major and overall complications, and eGFR changes. Moreover, subgroup analyses were conducted (MWA vs RFA; MWA vs CA; MWA vs RFA/CA in T1a renal tumors).

RESULTS

Ten retrospective studies with 2258 thermal ablations were included (508 MWA and 1750 RFA /CA). MWA had fewer local recurrences (OR = 0.31; 95% CI, 0.16, 0.62; p = 0.0008) than RFA/CA; the other outcomes were not significantly different. In subgroup analyses, MWA resulted to have fewer overall complications than RFA (OR = 0.60; 95% CI, 0.38, 0.97; p = 0.04) and CA (OR = 0.49; 95% CI, 0.28, 0.85; p = 0.01); moreover, MWA was associated with fewer recurrences than CA (OR = 0.30; 95% CI, 0.11, 0.84; p = 0.02). In T1a renal tumors subgroup analysis, the outcomes were not significantly different.

CONCLUSIONS

MWA is an ablative procedure as effective and safe as RFA or CA for the treatment of renal tumors.

Cryoablation and Immunotherapy: An Enthralling Synergy for Cancer Treatment

As less invasive options for surgical tumor removal, minimally invasive ablative techniques have gained popularity. Several solid tumors are being treated with cryoablation, a non-heat-based ablation technique. Cryoablation data in comparison over time demonstrates better tumor response and faster recovery. Combining cryosurgery with other cancer therapies has been explored to improve the cancer-killing process. Cryoablation with the combination of immunotherapy, results in a robust and efficient attack on the cancer cells. This article focuses on investigating the ability of cryosurgery to create a strong antitumor response when combined with immunologic agents resulting in a synergetic effect. To achieve this objective, we combined cryosurgery with immunotherapy using Nivolumab and lpilimumab. Five clinical cases of lymph node, lung cancer, bone, and lung metastasis were followed and analyzed. In this series of patients, percutaneous cryoablation and addressing immunity agents were technically feasible. In the follow-ups, there appeared to be no radiological evidence of new tumor development.

Radiofrequency ablation for renal tumours: A retrospective study from a tertiary centre

Objective

This study aimed to evaluate the safety and efficacy outcomes of percutaneous radiofrequency ablation (RFA) for localised renal cell carcinoma (RCC) in a tertiary hospital patient who remained unfit for surgical intervention.

Methods

We retrospectively analysed survival outcomes for patients with biopsy proven RCC treated by RFA at Royal Perth Hospital between September 2009 and May 2018. Complication data were gathered for all patients that underwent renal RFA along with 2- and 5-year recurrence-free survival (RFS) rate and compared the outcomes with data from previous studies.

Results

A total of 69 patients (73 procedures) were eligible for the study, and those patients had biopsy-proven RCC with a minimum of 2-year follow-up. The complication rate was 8.2% (6/73) and local recurrence rate 9.6% (7/73). Two-year RFS is 95.7% and 5-year RFS is 78.8% on a median 3.82-year follow-up (interquartile range 1.90-5.75 years).

Conclusion

RFA performed at our centre was found to be safe and effective with low complication rates and durable RFS in line with expectations from existing research. Our study demonstrated that RFA is an alternative modality of treatment for small renal tumours in patients unfit for surgical approach.

Radiofrequency Ablation, Cryoablation, and Microwave Ablation for the Treatment of Small Renal Masses: Efficacy and Complications

Over the last two decades the detection rate of small renal masses has increased, due to improving diagnostic accuracy, and nephron-sparing treatments have become the first-choice curative option for small renal masses. As a minimally invasive alternative, thermal ablation has increased in popularity, offering a good clinical outcome and low recurrence rate. Radiofrequency ablation, Cryoablation, and Microwave ablation are the main ablative techniques. All of them are mostly overlapping in term of cancer specific free survival and outcomes. These techniques require imaging study to assess lesions features and to plan the procedure: US, CT, and both of them together are the leading guidance alternatives. Imaging findings guide the interventional radiologist in assessing the risk of complication and possible residual disease after procedure. The purpose of this review is to compare different ablative modalities and different imaging guides, underlining the effectiveness, outcomes, and complications related to each of them, in order to assist the interventional radiologist in choosing the best option for the patient.

Magic bubbles: utilizing histotripsy to modulate the tumor microenvironment and improve systemic anti-tumor immune responses

Focused Ultrasound (FUS) is emerging as a promising primary and adjunct therapy for the treatment of cancer. This includes histotripsy, which is a noninvasive, non-ionizing, non-thermal ultrasound guided ablation modality. As histotripsy has progressed from bench-to-bedside, it has become evident that this therapy has benefits beyond local tumor ablation. Specifically, histotripsy has the potential to shift the local tumor microenvironment from immunologically 'cold' to 'hot'. This is associated with the production of damage associated molecular patterns, the release of a selection of proinflammatory mediators, and the induction of inflammatory forms of cell death in cells just outside of the treatment zone. In addition to the induction of this innate immune response, histotripsy can also improve engagement of the adaptive immune system and promote systemic anti-tumor immunity targeting distal tumors and metastatic lesions. These tantalizing observations suggest that, in settings of widely metastatic disease burden, selective histotripsy of a limited number of accessible tumors could be a means of maximizing responsiveness to systemic immunotherapy. More work is certainly needed to optimize treatment strategies that best synergize histotripsy parameters with innate and adaptive immune responses. Likewise, rigorous clinical studies are still necessary to verify the presence and repeatability of these phenomena in human patients. As this technology nears regulatory approval for clinical use, it is our expectation that the insights and immunomodulatory mechanisms summarized in this review will serve as directional guides for rational clinical studies to validate and optimize the potential immunotherapeutic role of histotripsy tumor ablation.

Percutaneous cryoablation combined with prior transcatheter arterial embolization for renal cell carcinomas of 3 cm or larger: a prospective study

BACKGROUND

We prospectively evaluated the safety and efficacy of percutaneous cryoablation combined with transcatheter renal arterial embolization for the treatment of tumors ≥ 3 cm in diameter.

METHODS

We included patients aged ≥ 20 years with histologically proven renal cell carcinoma with a tumor diameter ≥ 3 cm who were inoperable or refused surgery. Prior to ablation, transcatheter arterial embolization was performed using a mixture of absolute ethanol and iodized oil. All cryoablation procedures were performed percutaneously under computed tomography fluoroscopy guidance. The primary endpoint was safety, which was evaluated for adverse events using CTCAE version 4.0. The secondary endpoint was survival; overall survival, progression-free survival, and cancer-specific survival were calculated.

RESULTS

From October 2013 to March 2016, 19 patients (mean age, 75 ± 13 years; 5 women, 14 men) were prospectively enrolled. The mean tumor diameter was 3.9 ± 0.7 (range 3.1-5.3) cm. Four grade 3 hematologic adverse events occurred, while no symptomatic grade ≥ 3 events occurred. The median follow-up period was 68 (range 52-84) months. During the follow-up period, two patients developed local tumor progression at 3 and 42 months after the initial ablative procedure; no patient showed distant metastasis. Two patients died from causes other than RCC. Overall survival, progression-free survival, and cause-specific survival were 100%, 95%, and 100% at 3 years, and 95%, 84%, and 100% at 5 years, respectively.

CONCLUSION

Percutaneous cryoablation combined with prior TAE for the treatment of tumors ≥ 3 cm in diameter was safe and achieved favorable survival.

Diagnosis and Treatment of Small Renal Masses: Where Do We Stand?

PURPOSE OF REVIEW

To present an overview of the current evidence-based studies covering diagnostic and management of SRM.

RECENT FINDINGS

Renal cell carcinoma (RCC) represents 3% of the cancers. Nowadays, partial nephrectomy (PN) represents gold standard treatment. New nephron-sparing approaches such as active surveillance and ablative therapies have been increasingly used as an alternative to surgical intervention. Due to novel comprehension of RCC and widespread use of imaging techniques, diagnosis at early stage in elderly patients has increased. Treatment decision-making should be based on patient and tumour characteristics. With expanding treatment options, the management of SRMs has become a debate and should be adjusted to patient and tumour characteristics. In a shared decision manner, both active surveillance with possible delayed intervention and focal therapy should be discussed with the patient as an alternative to partial nephrectomy.

Comparison of Radiofrequency Ablation Versus Cryoablation For T1 Renal Tumors: An Evidence-Based Analysis of Comparative Outcomes

Objective

To discuss the differences in the effectiveness and security for T1 renal tumors by radiofrequency ablation (RFA) and cryoablation (CA).

Methods

We systematically searched the Cochrane Library, PubMed, Embase, CNKI databases, and Science databases, and the date was from the above database establishment to August 2021. Controlled trials on RFA and CA for T1 renal tumors were included. The meta-analysis was conducted with the Review Manager 5.4 software.

Results

A total of ten studies with 2,367 patients were included in the analysis. There were no significant differences in complications (odds ratio [OR], 1.23; 95% CI, 0.80 to 1.90; p=0.35), primary technique efficacy rate (OR, 1.01; 95% CI, 0.33 to 3.14; p=0.98), changes in serum creatinine (weighted mean difference [WMD], 0.53; 95% CI, -0.50 to 1.57; p=0.31), or 5-year survival rate (hazard ratio [HR], 1.11; 95% CI, 0.41 to 3.00; p=0.84) among patients undergoing RFA and CA. However, compared with patients who underwent RFA, patients who underwent CA had a lower Local recurrence (OR: 2.25; 95% CI: 1.38 to 3.67; p = 0.001).

Conclusion

The analysis demonstrated that in the treatment of T1 renal tumors, CA may be associated with lower local recurrence rates. However, no differences were observed in terms of primary technique efficacy rate, 5-year survival rate, changes in serum creatinine, and complication rate between groups.

Systematic Review Registration

[https://www.crd.york.ac.uk/PROSPERO/], identifier PROSPERO (CRD42021295160).

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.

Risk Factors for Renal Function Impairment Following Radiofrequency Ablation of Renal Tumors

Purpose

Materials and Methods

Results

Conclusion

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.

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.

[Percutaneous local ablation of small renal cell cancer]

Renal cell carcinoma (RCC) is a cancer that mainly occurs in elderly patients. Percutaneous image-guided ablation of small RCC (< 4 cm) is a validated therapeutic option, especially as many patients are no candidates for surgery due to comorbidities. This article presents and discusses established local ablative techniques such as radiofrequency (RFA), microwave (MWA) and cryoablation for the treatment of small RCC based on current literature and in the context of the latest guidelines.

Lung Ablation with Irreversible Electroporation Promotes Immune Cell Infiltration by Sparing Extracellular Matrix Proteins and Vasculature: Implications for Immunotherapy

Background: This study investigated the sparing of the extracellular matrix (ECM) and blood vessels at the site of lung irreversible electroporation (IRE), and its impact on postablation T cell and macrophage populations. Materials and Methods: Normal swine (n = 8) lung was treated with either IRE or microwave ablation (MWA), followed by sacrifice at 2 and 28 days (four animals/timepoint) after treatment. En bloc samples of ablated lung were stained for blood vessels (CD31), ECM proteins (Collagen, Heparan sulfate, and Decorin), T cells (CD3), and macrophages (Iba1). Stained slides were analyzed with an image processing software (ImageJ) to count the number of positive staining cells or the percentage area of tissue staining for ECM markers, and the statistical difference was evaluated with Student's t-test. Results: Approximately 50% of the blood vessels and collagen typically seen in healthy lung were evident in IRE treated samples at Day 2, with complete destruction within MWA treated lung. These levels increased threefold by Day 28, indicative of post-IRE tissue remodeling and regeneration. Decorin and Heparan sulfate levels were reduced, and it remained so through the duration of observation. Concurrently, numbers of CD3⁺ T cells and macrophages were not different from healthy lung at Day 2 after IRE, subsequently increasing by 2.5 and 1.5-fold by Day 28. Similar findings were restricted to the peripheral inflammatory rim of MWA samples, wherein the central necrotic regions remained acellular through Day 28. Conclusion: Acute preservation of blood vessels and major ECM components was observed in IRE treated lung at acute time points, and it was associated with the increased infiltration and presence of T cells and macrophages, features that were spatially restricted in MWA treated lung.

Image-Guided Thermal Ablation in De Novo Renal Tumor Arising in Kidney Allograft: 3-Year Follow-Up. A Case Report

De novo tumors in renal allograft recipients are a severe complication during long-term follow-up after transplantation and may require transplantectomy. Herein we present a case of de novo renal tumor arising in the renal allograft, treated with the less invasive image-guided radiofrequency ablation (RFA) with long-term follow-up. A tumor was detected during the routine annual follow-up in a patient with good renal function who underwent renal transplantation in 1989. Computed tomography (CT) showed a mass in the allograft whose shape, vascularization, and density suggested the presence of a solid, malignant mass, located in the upper renal pole, that measured 17 mm. CT-guided RFA was performed successfully, and the outcome was verified by an immediate control CT after the intervention. No residual pathologic tissue, major bleeding, or damage to the adjacent parenchyma was evidenced. The patient was discharged with stable renal function. CT scan and ultrasound were performed 3, 6, 12, 18, 24, and 36 months after RFA. No signs of change in renal function, recurrence, neovascularization, or damage to the adjacent microcirculation were observed during the 3-year follow-up. In conclusion, percutaneous RFA of small renal tumors occurring in renal allografts can be considered a function-sparing, safe, and effective therapeutic option when difficult surgical removal may be anticipated. Our experience also supports the need for yearly renal allograft ultrasound follow-up for early identification of small neoplasm than can be treated less invasively.

Image-guided percutaneous cryoablation of T1b renal cell carcinomas in patients with comorbidities

PURPOSE

To investigate the influence of comorbidities and tumor characteristics on outcomes following percutaneous cryoablation (PCA) of T1b renal cell carcinoma (RCC).

MATERIALS AND METHODS

Age-adjusted Charlson comorbidity index (ACCI); standardized system for quantitating renal tumor size, location, and depth (RENAL nephrometry score [RNS]); and local tumor control and survival were retrospectively investigated in 28 patients who underwent PCA for stage T1b RCC. Risk factors for elevated serum creatinine levels were also investigated.

RESULTS

Complete ablation was obtained in 27 of 28 patients. Two cases of metastasis were observed; one patient died 12 months after PCA. Overall survival at 5 years was 79.1%, with a mean follow-up of 42.0 ± 16.0 months. Local tumor control was not correlated with the ACCI and RNS. Worsening renal function 3 months after PCA was observed in ten patients, and it correlated with the presence of single kidneys (7/28 patients; p = 0.023). Significant worsening of renal function continued until 1 year after PCA (p = 0.013). Having a single kidney was a risk factor for worsened renal function after PCA (odds ratio, 8.00; 95% confidence interval 1.170-54.724).

CONCLUSION

PCA for T1b RCC confers positive local tumor control regardless of comorbidities and tumor characteristics.

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.

A Hybrid Approach for Treating Recurrent Renal Cell Carcinoma (RCC) in a Single Kidney with a Tethered Ureter

This case highlights a hybrid treatment model used successfully in a patient with complicated recurrent renal cell carcinoma (RCC), following partial nephrectomy, in the context of a single kidney. Scar tissue from previous surgery tethered the ureter to the margin of the lesion and combined with obesity, rendered simple percutaneous intervention challenging. The patient was ultimately successfully treated using a hybrid approach of open surgical access, ureterolysis, and intraoperative ultrasound-guided radiofrequency ablation. This approach optimized the volume of conserved normal renal parenchyma and eliminated the need for postoperative dialysis treatment, with no recurrence at 13 months follow-up.

Long-term oncological outcomes for radiofrequency ablation of small renal masses

Objective:

To describe oncology outcomes and complications with radiofrequency ablation (RFA) for T1 renal cell carcinoma in a centre with 14 years of experience.

Method:

Retrospective study of 95 consecutive patients from 2005 to 2013 who underwent RFA. Those with metastatic disease at time of treatment, incomplete follow up, proven benign pathology, genetic underlying genetic pre-disposition were excluded. 48 patients with 49 tumours met the inclusion criteria. Data was collected on demographics oncological outcomes and complications. Primary outcome measures were disease free survival and cancer specific survival at five and eight years.

Results:

Median follow up was 83 months. We demonstrate an 87% 5-year disease free survival (DFS) and 70% eight-year DFS. Mean time to progression was 45 months. Cancer specific survival was demonstrated as 97.9% at five years and 93.6% at eight years – all cancer-related deaths had an initial tumour of > 3 cm diameter. 42.9% of the recurrences occurred beyond five years The median time to progression for secondary failure was 50.7 months. One Clavien-Dindo Grade 2 complication was encountered in the series.

Outcome:

RFA produces comparable long-term oncological outcomes to other modalities for T1 tumours with a low complication rate. Follow up should be considered beyond five years as a significant proportion of the recurrences (42.9%) in this study occurred beyond this point. Level of evidence: 4

[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.

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.

A Case Series of Delayed Proximal Ureteral Strictures After Nephron-Sparing Treatment of Renal Masses

Background: Delayed proximal ureteral stricture (DPUS) after nephron-sparing treatment (partial nephrectomy [PN] and image-guided percutaneous ablation) of renal masses is a rare complication that occurs because of an unrecognized injury to the proximal ureter and/or its associated vascular supply. We present a multi-institutional series of patients who developed DPUS after nephron-sparing treatment and review relevant tumor characteristics, timing of DPUS presentation, presenting symptoms, and outcome of stricture management. Case Presentation: Between 2000 and 2019, nine patients (five PN and four ablation) were found to have DPUS diagnosed at an average of 9 (6-119) months after PN and 5.5 (1-6) after ablation. Average tumor size was 4.5 (2.9-7.3) cm and 3.6 (3-4.1) cm for those treated with PN and ablation, respectively. Nephrometry score was 8.3 (6-11) and 6.5 (5-8), respectively. For resected tumors, all were located in the lower pole, but uniformity was not found as far as medial vs lateral (3 vs 2), anterior vs posterior (2 vs 2, 1 N/A), and right vs left (3 vs 2). For ablated tumors, all four tumors were right sided, anterior, medial, and lower pole. Initial signs and symptoms include sepsis (2), flank pain (5), and asymptomatic hydronephrosis (2). Concomitant urinoma (2) and retroperitoneal abscess (1) was found on imaging. Initial management included ureteral stenting (5) and percutaneous nephrostomy tube (4). Three underwent nephrectomy. Two had spontaneous resolution of DPUS after a course of ureteral stenting. Conclusion: Potential risk factors associated with DPUS after nephron-sparing treatment, including medial and lower pole tumors, and particularly right-sided anterior masses for ablation and higher complexity nephrometry score for PN. Recognition of delayed symptoms and imaging abnormalities in the surveillance period should cue clinical suspicion to DPUS.

Percutaneous Adrenal Radiofrequency Ablation: A Short Review for Endocrinologists

Image-guided radiofrequency ablation (RFA) has been accepted as a minimally invasive treatment for adrenal tumors in patients who are unable to undergo adrenalectomy. Accordingly, this treatment has become more readily available for treating functioning or non-functioning adrenal masses. Thus, endocrinologists need a better understanding of percutaneous RFA of adrenal tumors. The purpose of this review is to briefly describe the basic mechanism of RFA, indications and contraindications, patient preparation prior to RFA, type of complications, how to avoid complications, RFA procedures, and treatment outcomes.

Comparison of Safety and Efficacy of Percutaneous Microwave Ablation of Central Versus Peripheral Renal Cell Carcinoma

PURPOSE

Thermal ablation of central renal cell carcinoma has been associated with increased risk of incomplete tumor necrosis and adverse events due to the proximity of tumors to the central collecting system and hilar vessels. The purpose of this study was to compare the safety and efficacy of computed tomography-guided percutaneous microwave ablation of central versus peripheral renal cell carcinoma.

MATERIALS AND METHODS

An institutional database was used to retrospectively identify 114 patients with renal cell carcinoma who were treated with computed tomography-guided percutaneous microwave ablation between January 2015 and December 2019. Patients were divided into two cohorts based on tumor location: central versus peripheral. Central renal tumors were defined as being within 4 mm of renal pelvis and/or ureter and peripheral tumors were defined as tumors beyond 4 mm the renal pelvis and/or ureter. Patient demographics, tumor type, technical success, primary technique efficacy and adverse events were recorded from the medical record. Technical success, primary technique efficacy and adverse events were compared between the two cohorts.

RESULTS

There were 44 patients in the central group and 70 patients in the peripheral group. Technical success was 100% for both groups. There was no significant difference in primary technique efficacy rates for peripheral compared to central tumors (93% vs. 89%, p = 0.49). There was no significant difference in overall adverse event rate (17.7% vs. 11.7%, p = 0.34) or Grade II or higher adverse event rate (7.8% vs. 2.6%, p = 0.17) following microwave ablation of central versus peripheral lesions. Adjunctive maneuvers of hydrodissection and/or pyeloperfusion were performed significantly more frequently for treatment for central tumors compared to peripheral tumors (53% vs. 29%, p = 0.006).

CONCLUSION

When adjunctive procedures were utilized more frequently for central compared to peripheral tumors, there was no significant difference in primary technique efficacy or adverse event rate following CT-guided percutaneous microwave ablation of central compared to peripheral renal cell carcinoma. The data suggest that MWA can be successfully applied to select central renal masses and adjunctive maneuvers such as pyeloperfusion should be strongly considered for patient safety.

LEVEL OF EVIDENCE III

Non-randomized controlled cohort study/follow-up study.

Phase Contrast Imaging Based Microbubble Monitoring of Radiofrequency Ablation: An ex vivo Study

Background

To explore the potential of synchrotron radiation (SR) phase contrast imaging (PCI) for real-time microbubble formation monitoring during radiofrequency ablation (RFA).

Methods

RFA was performed on ex vivo porcine muscle tissue using unipolar and multi-tined expandable electrodes. Images of microbubble formation in the samples were captured by both SR PCI and absorption contrast imaging. The synchronous ablation temperature was recorded. Each RFA electrode type group contained 6 samples. Ablation size was assessed by histologic examination.

Results

Microbubble formation during RFA could be visualized by SR PCI. The diameter of the microbubbles revealed on the image ranged from tens of microns to several millimeters, and these microbubbles first appeared at the edge of the RFA electrode when the target region temperature reached approximately 60°C and rapidly extended outwards. The average microbubble range measured on PCI was 17.66 ± 0.74 mm. The average range of coagulation necrosis measured by histological examination was 17.22 ± 0.38 mm. There was no significant difference between them (P > 0.05). The range of microbubbles corresponded to the ablation zone.

Conclusion

PCI enabled real-time high-resolution visualization of microbubble formation during RFA, indicating a potential for its use in ablation monitoring.

Invasive management of renal cell carcinoma in von Hippel-Lindau disease

Introduction

Patients affected by von Hippel-Lindau (VHL) disease experience an increased risk for bilateral, synchronous, and metachronous renal cell carcinoma (RCC). Oncologic and functional outcomes are the main goals in the management of renal masses. We present our protocol for patients with VHL disease-associated RCC alongside functional and oncologic results observed in our series.

Material and methods

We performed a retrospective analysis of our clinical database of patients with VHL disease-associated RCC referred to our department between June 2005 and December 2017. We offer surveillance for lesions <2 cm and active management with radiofrequency ablation (RFA) for lesions 2-3 cm, and nephron-sparing surgery (NSS), RFA or embolization techniques for lesions >3 cm or growth rate >1 cm/year.

Results

Our series comprises 14 patients, of whom 13 had undergone at least one invasive procedure for RCC, mean age at first intervention was 27 years (range 18-60). Overall, 30 interventions were performed in 21 kidneys: four radical nephrectomies, 13 RFAs, 12 NSSs, and one embolization. During follow-up (median time: 41 months, range: 6-149), eight patients (57%) presented with new lesions that required treatment, with a mean time between treatments of 32 ±18.5 months. No metastatic progression or need for dialysis was recorded; the success rate for RFA was 85%.

Conclusions

Management of VHL kidney disease by NSS is the standard of care with a cut-off at 3 cm, ablative procedures should be offered to lesions ranging 2-3 cm in size. Follow-up should be done strictly in referral centers that can provide all treatment options to renal function and control oncologic progression.

Understanding Factors Governing Distribution Volume of Ethyl Cellulose-Ethanol to Optimize Ablative Therapy in the Liver

OBJECTIVE

Ethanol ablation, the injection of ethanol to induce necrosis, was originally used to treat hepatocellular carcinoma, with survival rates comparable to surgery. However, efficacy is limited due to leakage into surrounding tissue. To reduce leakage, we previously reported incorporating ethyl cellulose (EC) with ethanol as this mixture forms a gel when injected into tissue. To further develop EC-ethanol injection as an ablative therapy, the present study evaluates the extent to which salient injection parameters govern the injected fluid distribution.

METHODS

Utilizing ex vivo swine liver, injection parameters (infusion rate, EC%, infusion volume) were examined with fluorescein added to each solution. After injection, tissue samples were frozen, sectioned, and imaged.

RESULTS

While leakage was higher for ethanol and 3%EC-ethanol at a rate of 10 mL/hr compared to 1 mL/hr, leakage remained low for 6%EC-ethanol regardless of infusion rate. The impact of infusion volume and pressure were also investigated first in tissue-mimicking surrogates and then in tissue. Results indicated that there is a critical infusion pressure beyond which crack formation occurs leading to fluid leakage. At a rate of 10 mL/hr, a volume of 50 μL remained below the critical pressure.

CONCLUSIONS

Although increasing the infusion rate increases stress on the tissue and the risk of crack formation, injections of 6%EC-ethanol were localized regardless of infusion rate. To further limit leakage, multiple low-volume infusions may be employed.

SIGNIFICANCE

These results, and the experimental framework developed to obtain them, can inform optimizing EC-ethanol to treat a range of medical conditions.

Microwave ablation: How we do it?

Minimally invasive techniques such as Image guided thermal ablation are now widely used in the treatment of tumors. Microwave ablation (MWA) is one of the newer modality of thermal ablation and has proven its safety and efficacy in the management of the tumors amenable for ablation for primary and metastatic diseases. It is used in the treatment of primary and secondary liver malignancies, primary and secondary lung malignancies, renal and adrenal tumors and bone metastases. We wanted to share our initial experience with this newer modality. In this article we will describe the mechanism and technique of MWA, comparison done with RFA, advantages and disadvantages of MWA along with pre procedure workup, post procedure follow-up and review of literature.

Percutaneous Renal Ablation

Incidental small renal cell cancers are increasingly being diagnosed on cross-sectional imaging. This review article describes the indications for percutaneous ablation of small renal cell cancers, choice of ablation technologies and imaging follow-up.

Percutaneous ablation techniques for renal cell carcinoma: current status and future trends

Percutaneous ablation is an increasingly applied technique for the treatment of localized renal tumors, especially for elderly or co-morbid patients, where co-morbidities increase the risk of traditional nephrectomy. Ablative techniques are technically suited for the treatment of tumors generally not exceeding 4 cm, which has been set as general consensus cutoff and is described as the upper threshold of T1a kidney tumors. This threshold cutoff is being challenged, but with still limited evidence. Percutaneous ablation techniques for the treatment of renal cell carcinoma (RCC) include radiofrequency ablation, cryoablation, laser or microwave ablation; the main advantage of all these techniques over surgery is less invasiveness, lower complication rates and better patient tolerability. Currently, international guidelines recommend percutaneous ablation either as intervention for frail patients or as a first line tool, provided that the tumor can be radically ablated. The purpose of this article is to describe the basic concepts of percutaneous ablation in the treatment of RCC. Controversies concerning techniques and products and the need for patient-centered tailored approaches during selection among the different techniques available will be discussed.

Ablation of Small Renal Masses

Renal cell carcinoma is most commonly diagnosed in the sixth or seventh decade of life. Historically, surgical extirpation was the gold standard treatment option for small renal masses. However, given the comorbidities in this elderly population, not all patients are candidates for surgery. The development of minimally invasive ablative therapies has solved the surgical dilemma in this patient population. Furthermore, the 2017 American Urological Association guidelines recommends consideration of percutaneous image guided thermal ablation as a treatment option for masses smaller than 3 cm even in healthy individuals. Percutaneous image guided thermal ablation is an attractive treatment option providing excellent local tumor control, fewer complications, better preservation of the renal functions, faster recovery and shorter hospital stay. Various ablative modalities are available in clinical practice. This includes radiofrequency ablation, cryoablation, microwave ablation, irreversible electroporation, high intensity focused ultrasound, and laser ablation. In this review, we focus on the most commonly used modalities including radiofrequency ablation and cryoablation and to a lesser extent microwave ablation and irreversible electroporation.

Early trends and predictors of renal function following computed tomography-guided percutaneous cryoablation of a renal mass in patients with and without prior renal impairment

OBJECTIVE

To assess trends and predictors of the glomerular filtration rate (GFR) after renal mass cryoablation in patients with and without history of renal impairment.

MATERIALS AND METHODS

This was a retrospective study of 39 patients who underwent computed tomography-guided percutaneous cryoablation of a renal mass, divided into two groups: those with prior renal impairment (PRI+); and those without prior renal impairment (PRI-). The GFR trend and the chronic kidney disease stage were evaluated at baseline, as well as at 1, 6, and 12 months after cryoablation. Predictors of GFR at 1 and 6 months were modeled with linear regression.

RESULTS

In both groups, the mean GFR at 1 month and 6 months was significantly lower than at baseline (p < 0.001 and p = 0.01, respectively). Although the GFR was lower across all time points in the PRI+ group (-26.1; p < 0.001), the overall trend was not statistically different from that observed in the PRI- group (p = 0.89). Univariate analysis showed that the decline in GFR at 1 and 6 months correlated with the baseline GFR (0.77 and 0.63; p < 0.001 and p = 0.03, respectively) and with the size of the ablation zone (-7.6 and -12.84, respectively; p = 0.03 for both). However, in the multivariate model, baseline GFR was predictive only of GFR at 1 month (p < 0.001).

CONCLUSION

The trend in GFR decline after cryoablation is similar for patients with and without a history of renal impairment. Baseline GFR predicts the mean GFR in the early post-cryoablation period.

Radiofrequency ablation (RFA) of T1a renal cancer with externally cooled multitined expandable electrodes

INTRODUCTION

To retrospectively evaluate the mid-term outcomes of percutaneous radiofrequency ablation (RFA) with multitined expandable electrodes externally cooled with saline solution in patients with T1a renal cell carcinoma (RCC).

MATERIALS AND METHODS

In this retrospective study, we evaluated 39 RCC in 35 patients treated with CT-guided RFA in 41 procedures (2011-2017). All patients were staged T1a, N0, M0 prior to RFA. Mean tumor size was 24.48 mm. A 4-tined expandable RFA electrode cooled with pump-circulating saline was used. Efficacy was evaluated verifying complete tumor necrosis (no contrast enhancement on imaging) at the end of the procedure and on subsequent controls. Follow-up observation period was 5 years. Minor/major complications, hospitalization days, serum creatinine and GFR pre- and post-RFA (compared using paired t test) and post-operative pain (evaluated with NRS after treatment) were considered as safety indicators. Overall survival was also calculated (Kaplan-Meier method).

RESULTS

Of 35 patients, 30/35 had 1 treatment (primary effectiveness rate 86%), 4/35 had 2 treatments and 1/35 had 3 treatments for residual disease. There were no relapses and no mid-long-term complications; 3 minor (8%) and 1 major (2.7%) complications during perioperative period were reported. Mean before and after RFA serum creatinine rates were, respectively, 1.08 mg/dl and 1.11 mg/dl (p value: 0.4117). NRS median value is 0.8. Hospitalization days median value is [2.8 ± 1.9] days. 91.4% of all patients survived, with a median overall survival time of 65 months.

CONCLUSIONS

Mid-term results show that CT-guided RFA with multitined expandable electrodes externally cooled with saline solution is an effective and safe treatment in patients with RCC-staged T1aN0M0. Data reported in our study are in line with data reported in the literature from patients treated with other devices.

ABLATE: a score to predict complications and recurrence rate in percutaneous treatments of renal lesions

RENAL score has been validated on predicting adverse events and relapses in percutaneous treatments of renal lesions. To better fit interventional issues a modified score (mRENAL) has been introduced, but the only difference from the RENAL score is on the dimensional parameter. However, it remains of surgical derivation while a specific interventional score is missing. This study aims to obtain a specific score (ABLATE) to better quantify the risk of complications and relapses in percutaneous kidney ablation procedures compared to the existing surgical scores. Taking inspiration from previous papers, a score was built to quantify the real difficulties faced in percutaneous treatment of renal lesions. The ABLATE score was used on 71 cryoablations to evaluate its predictivity of complications and relapses. Logistic regression was used to predict complication incidence; Cox-regression was used for relapses; ROC analysis was used to evaluate the accuracy of the different scores. Between January 2014 and November 2019, 71 lesions in 68 patients were treated. Overall, malignant histology was found in 62 lesions (87.3%). Mean and median RENAL, mRENAL, and ABLATE scores were 7.04 and 7, 7.19 and 7, and 5.11 and 4, respectively. Out of 71 treatments, we experienced 3 bleeding with anemia (4.2%), only 2 of which needed further treatment (2.82%). The mean and median RENAL, mRENAL, and ABLATE scores in those with complications were 7.66 and 7.01 (p = 0.69), 8.0 and 7.1 (p = 0.54), and 6.6 and 5.0 (p = 0.38), respectively. Out of 62 malignant lesions, we experienced 2 persistent and 6 recurrent lesions (3.2% and 8.4%, respectively). At Cox-regression analyses, mABLATE score outperformed both RENAL and mRENAL scores in predicting recurrences (HR 1.48; p < 0.001 vs. 1.41; p = 0.1 vs. 1.38: p = 0.07, respectively). The ABLATE score showed to be a better predictor of relapses than RENAL and mRENAL. The small number of complications conditioned a lack of statistic power on complications for all the scores. At the moment to quantify the risks in percutaneous kidney ablation procedures, surgical scores are used. A specific score better performs this task.

Percutaneous cryoablation vs. open partial nephrectomy in small kidney cancers: the Italian experience

INTRODUCTION

The aim of the present work was to analyze the economic impact of PCA (percutaneous cryoablation) vs. OPN (open partial nephrectomy), as it represents the most common standard of care for SRMs (small renal masses), namely T1a renal cancers (<4 cm), in Italy.

EVIDENCE ACQUISITION

A cost analysis was performed to compare the difference of the total perioperative costs between PCA and OPN, both from the perspective of the National Healthcare System and the hospital. Clinical and resources consumption inputs were retrieved by a non-systematic literature search on scientific databases, complemented by a grey literature research, and validated by expert opinion. Costs calculation for the NHS perspective were based on reference tariffs published by the National Ministry of Health, while for the hospital perspective, unit costs published in the grey literature were used to compare the two alternatives.

EVIDENCE SYNTHESIS

Assuming the NHS perspective, the cost analysis shows there is an economic advantage in using PCA vs. OPN (€4080 vs. €7541) for the treatment of SRMs. Hospitalization time is the driver of the total costs, while the costs of complications are quite negligible in both groups. From the hospital perspective the costs of PCA is slightly higher (+€737) than OPN, with cryoprobes contributing as the greatest cost component. However, this increase is quite restrained and is offset by an inferior use of healthcare resources (surgery room, healthcare personnel, length of stay in the hospital).

CONCLUSIONS

According to our analysis, PCA results an advantageous technique compared to OPN respectively in terms of costs and resource consumption from both the NHS and the hospital perspective.

Comparison of clinical outcome between pyeloperfused versus non-pyeloperfused microwave ablation of renal cell carcinoma

Purpose

We present the outcomes of microwave ablation (MWA) of renal cell carcinoma (RCC) with and without pyeloperfusion.

Material and methods

A retrospective review of patients’ records was undertaken to identify patients with RCC, who were treated with MWA with and without adjunctive pyeloperfusion. The distance between the tumour and ureter as well as the tumour size were measured on axial imaging. Pyeloperfusion was performed in nine patients in this series after placement of a ureteral stent and instilment of diluted contrast into the ureter. MWAs of the tumours were performed under computed tomography (CT) guidance. Hydrodissection was performed to displace at-risk organs. Creatinine was measured as renal function index after and before the procedure. A CT scan was performed at the end of the procedure and also after one, three, and six months, to identify the presence of residual disease and complications.

Results

Eighteen biopsies of proven RCC were treated with 20 sessions of MWA. The average follow-up time for this study was 180 days. The average distance between the ureter and the tumour in axial CT view was 20.8 (± 2.9) mm. Primary efficacy was achieved in 88% of pyeloperfused patients and in 100% of the non-pyeloperfused patients. Two pyeloperfused patients required secondary procedure, and full secondary efficacy was achieved for both. There was only one grade 2 urological complication, which occurred in a patient who underwent pyeloperfusion. Creatinine was not significantly different after the procedure in this study (p-value 0.4).

Conclusion

In this study MWAs of RCCs were successfully performed using pyeloperfusion as a protective measure against thermal injury to the ureter.

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.

Active surveillance and focal ablation for small renal masses: a better solution for comorbid patients

The natural history of small renal masses (SRM) is still not well understood and they are frequently incidentally diagnosed in elderly patients. Therefore, there is a need for less invasive options sparing the patient from the side-effects related to conventional surgical treatment. PubMed and Medline database search was performed to look for new findings on active surveillance and focal therapy for SRM. Sixty-one articles published between 2002 and 2018 were selected for the purpose of the review. There is growing evidence confirming the safety of active surveillance in patients at surgical risk and there appears to be a satisfactory intermediate-term outcome of focal treatment of SRM. In the group of elderly patients with a decreased life expectancy active surveillance appears to be the most appropriate approach. The future of minimally invasive therapy appears bright, especially with the improvement of new imaging modalities.

Anesthesia for Percutaneous Radiofrequency Tumor Ablation (PRFA): A Review of Current Practice and Techniques

Percutaneous radiofrequency ablation (PRFA) of solid tumors is a minimally invasive procedure used to treat primary or metastatic cancer lesions via needle targeted thermal energy transfer. Some of the most common tumor lesions treated using PRFA include those within the liver, lungs and kidneys. Additionally, bone, thyroid, and breast lesions can also be treated. In most cases, this procedure is performed outside of the operating room in a specialized radiology suite. As a result, the clinician must adapt in many cases to the specific environmental issues attendant to providing anesthesia outside the operating room, including the lack of availability of an anesthesia machine in some cases, and frequently a lack of adequate scavenging and other specialized monitoring and equipment. At this time, routine practice and anesthetic prescriptions for PRFA can vary widely, ranging from patients receiving local anesthesia alone, to monitored anesthesia care, to regional anesthesia, to combined regional and general anesthesia. The choice of anesthetic technique will depend on tumor location and practitioner experience. This review aims to summarize the current state of the art in terms of anesthetic techniques for patients undergoing PRFA of solid tumors.

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.