Renal tumor ablation

Effects of percutaneous cryoablation for renal tumor on overall and split renal function

PURPOSE

To evaluate retrospectively the influence of percutaneous cryoablation for small renal tumors on total and affected kidney function and risk factors associated with worsening function of the affected kidney.

MATERIALS AND METHODS

Between April 2016 and March 2022, 27 patients who underwent cryoablation for small renal tumors at our institution participated in this study, which investigated time-dependent changes in postoperative renal function. We evaluated estimated glomerular filtration rates (eGFRs) and split renal function revealed by scintigraphy using 99 m technetium-mercaptoacetyltriglycine (99mTc-MAG3) before cryoablation and at 1 week, 1 month, and 6 months after cryoablation. Numerous variables were analyzed to assess risk factors for worsening renal function.

RESULTS

Baseline eGFR (mean ± standard deviation) was 56.5 ± 23.7 mL/min/1.73 m2 (mean ± SD; range, 20.5-112.5). Mean eGFRs at 1 week, 1 month, and 6 months after cryoablation were 57.4 ± 24.5 (19.1-114.9), 57.1 ± 25.1 (21.5-114.9), and 53.8 ± 23.9 mL/min/1.73 m2 (20.0-107.5), respectively. Changes were statistically insignificant (p = 1.0000, = 0.6749, and = 0.0761, respectively). Regarding split renal function, mean baseline contribution of the affected kidney determined by 99mTc-MAG3 was 49.7% ± 6.0% (38.8-63.3%); these rates at 1 week, 1 month, and 6 months after cryoablation were 43.7% ± 8.8 (29.1-70.6%), 46.2% ± 7.7% (32.6-70.3%), and 46.0% ± 8.5% (32.5-67.6%), respectively. Differences from baseline were significant for all periods (p < 0001, < 0001, = 0.0001, respectively). Serum C reactive protein and lactate dehydrogenase at 1 day following cryoablation, tumor's nearness to the collecting system or sinus, and volume of ablated normal renal parenchyma were significantly correlated with decreased contributions of the affected kidney by > 10% after cryoablation.

CONCLUSION

Unlike total renal function, affected kidney function could worsen after cryoablation.

Percutaneous radiofrequency ablation is an effective treatment option for small renal masses, comparable to partial nephrectomy

OBJECTIVES

The standard therapy for small renal masses (SRMs) remains partial nephrectomy (PN), which is associated with relatively high morbidity and complication rate. Therefore, percutaneous radiofrequency ablation (PRFA) emerges as an alternative therapy. This study aimed to compare the efficacy, safety, and oncological outcomes of PRFA versus PN.

METHODS

A multicenter non-inferiority study with retrospective analysis of 291 patients with SRMs (N0M0), who underwent PN or PRFA (2:1), recruited prospectively from two hospitals in the Andalusian Public Health System, Spain, between 2014 and 2021. Comparisons of treatment features were evaluated using the t test, Wilcoxon-Mann-Whitney U test, chi-square test, Fisher test, and Cochran-Armitage trend test. Kaplan-Meier curves depicted overall survival (OS), local recurrence-free survival (LRFS), and metastasis-free survival (MFS) rates in the overall study population.

RESULTS

A total of 291 consecutive patients were identified; 111 and 180 patients underwent PRFA and PN, respectively. Median follow-up time was 38 and 48 months, and mean hospitalization days were 1.04 and 3.57 days, respectively. The variables underpinned with high surgical risk were significantly increased in PRFA compared to those in PN (mean age was 64.56 and 57.47 years, the solitary kidney presence was 12.6% and 5.6%, ASA score ≥ 3 was 36% and 14.5%, respectively). The rest of oncological outcomes were comparable amongst PRFA and PN. Patients undergoing PRFA did not improve OS, LRFS, and MFS compared to those undergoing PN. Limitations comprise retrospective design and limited statistical power.

CONCLUSION

PRFA for SMRs in high-risk patients is non-inferior in terms of oncological outcomes and safety compared to PN.

CLINICAL RELEVANCE STATEMENT

Our study has a direct clinical application as it proves that radiofrequency ablation is an effective and uncomplicated therapeutic option for patients with small renal masses.

KEY POINTS

•There are non-inferiority results in overall survival, local recurrence-free survival, and metastasis-free survival between PRFA and PN. •Our two-center study showed that PRFA is non-inferior to PN in oncological outcomes. •Contrast-enhanced power ultrasound-guided PRFA provides an effective therapy for T1 renal tumors.

Clinical Experience of Percutaneous Radiofrequency Ablation Using an arfa RF ABLATION SYSTEMⓇ in Various Organs

PURPOSE

To evaluate the feasibility, safety, and efficacy of radiofrequency (RF) ablation using an ablation system (arfa RF ABLATION SYSTEM^Ⓡ; Japan Lifeline Co. Ltd.) for treating solid tumors in various organs.

MATERIAL AND METHODS

Between October 2019 and August 2021, 80 patients (29 women, 51 men; median age, 70.0 yr) underwent 107 RF ablation sessions using the ablation system to treat 151 tumors in the liver (n = 86), lung (n = 51), adrenal gland (n = 4), pleura (n = 4), bone (n = 3), lymph node (n = 2), and kidney (n = 1). The maximum tumor diameter was 2-40 mm (median, 11 mm). This study evaluated technical success (defined as the completion of planned RF ablation), technique efficacy (defined as the complete tumor ablation on follow-up images), and adverse events. Local tumor progression in 146 curatively treated malignant tumors was evaluated.

RESULTS

The technical success rate was 100% (107/107). Ablation zones in two tumors were insufficient. Therefore, the primary technique efficacy rate was 98.1% (105/107). Grade 3 hepatic infarction (1.6%, 1/64) and grade 4 pleuritis (3.4%, 1/29) occurred respectively after liver and lung RF ablation. During the median follow-up period of 10.2 months (Interquartile range, 4.2 and 16.4 months), local tumor progression developed in two tumors (1.4%, 2/146).

CONCLUSIONS

The arfa RF ABLATION SYSTEM^Ⓡ is a feasible, safe, and effective RF ablation device for managing solid tumors in various organs.

Long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring selective transarterial embolization

PURPOSE

To determine long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring transarterial embolization compared to patients who underwent uncomplicated renal cryoablation without major hemorrhage.

METHODS

Utilizing a matched cohort study design, retrospective review identified 23 patients who underwent percutaneous image-guided renal cryoablation complicated by major hemorrhage requiring ipsilateral transarterial embolization (TAE group) and a control group of 23 patients who underwent uncomplicated renal cryoablation matched 1:1 by age, gender and RENAL Nephrometry score at a single institution from 1/1/2005 to 12/31/2019. Primary outcome parameters included change in creatinine (mg/dl) and estimated glomerular filtration rate (ml/min/1.73 m²; eGFR) from baseline and were compared between TAE and control group using a paired t-test.

RESULTS

There was a significantly higher proportion of patients on pre-ablation anticoagulation in the TAE v. control group (30% v. 4%; p = 0.047), but all patients were off anticoagulation and with normal coagulation parameters at the time of cryoablation. Otherwise there were no significant differences in clinical, renal tumor, Charlson co-morbidity index, baseline renal function or cryoablation parameters between the TAE and control group. In the post-ablation period, there was trend toward greater increase in creatinine from baseline to worst post-ablation creatinine in the TAE v. the control group (+ 0.5 ± 0.7 mg/dl v. 0.2 ± 0.1 mg/dl; p = 0.056). However, at a mean follow-up of 42.7 ± 35.7 months, there was no significant difference between the TAE and control group in creatinine (p = 0.68), eGFR (p = 0.60) or change from baseline in creatinine (p = 0.28), eGFR (p = 0.80) or CKD stage (p = 0.74). No patient required initiation of hemodialysis.

CONCLUSION

Selective transarterial embolization for post-renal cryoablation hemorrhage does not significantly affect long-term renal function compared to cryoablation alone. Pre-ablation anticoagulation despite normal coagulation at time of ablation may be a risk factor for post-ablation hemorrhage, and warrants further evaluation when considering pre-ablation embolization.

Radiology- and gene-based risk stratification in small renal cell carcinoma: A preliminary study

PURPOSE

Most small renal cell carcinomas (small RCCs) will remain indolent after detection, but some stage I RCCs still metastasize. There are no risk-stratification imaging factors that could be used to identify poor-prognosis patients based on genomic profiling. Here, we evaluated the relationships between imaging parameters and RNA expressions in small RCC and attempted to identify imaging factors that could be used as effective biomarkers.

METHODS

We acquired biopsy specimens of 18 clear cell carcinomas that had undergone perfusion CT (pCT) and MRI between April 2018 and March 2019. We performed RNA sequencing, assessed RNA expressions, and calculated each tumor's cell-cycle progression (CCP) score, which has prognostic value in predicting metastatic progression. We classified the tumors into two groups: clear cell type A (ccA) and type B (ccB). CcA has better survival compared to ccB. We evaluated the following characteristics of each tumor: tumor size, presence of pseudocapsule, and fat. We used the pCT and MRI to measure each tumor's volume transfer constant (Ktrans), rate constant (Kep), extracellular extravascular volume fraction (VE), fractional plasma volume (VP), and apparent diffusion coefficient (ADC). The correlations between these small RCC imaging parameters and the tumor size and RNA expressions were determined.

RESULTS

The tumor size was significantly correlated with Kep and inversely correlated with VE, VP, ADC, and hallmark angiogenesis. The CCP score was significantly inversely correlated with Ktrans and Kep. The ccA tumors tended to show a pseudocapsule on MRI.

CONCLUSION

Tumor size was correlated with low perfusion, but not with prognostic factors based on genomic profiling. Imaging parameters (e.g., Ktrans and Kep) and tumor characteristics (e.g., pseudocapsule) may enable gene-based risk stratification in small RCC.

[Ablative therapy of small renal masses]

Renal cell cancer is nowadays predominantly diagnosed in early stages due to the widespread use of sectional imaging for unrelated symptoms. Small renal masses (<4 cm) feature a largely indolent biology with a very low risk for metastasis or even a benign biology in up to 30% of the cases. Consequently, there is a need for less invasive therapeutic alternatives to nephron-sparing surgery. Meanwhile, there is a broad portfolio of local ablation techniques to treat small renal tumors. These include the extensively studied radiofrequency ablation and cryoablation techniques as well as newer modalities like microwave ablation and irreversible electroporation as more experimental techniques. Tumor ablation can be performed percutaneously under image guidance or laparoscopically. In particular, the percutaneous approach is a less invasive alternative to nephron-sparing surgery with lower risk for complications. Comparative studies and meta-analyses report a higher risk for local recurrence after renal tumor ablation compared to surgery. However, long-term oncological results after treatment of small renal masses are promising and do not seem to differ from partial nephrectomy. The possibility for salvage therapy in case of recurrence also accounts for this finding. Especially old patients with an increased risk of surgical and anesthesiological complications as well as patients with recurrent and multiple hereditary renal cell carcinomas may benefit from tumor ablation. Tumor biopsy prior to intervention is associated with very low morbidity rates and is oncologically safe. It can help to assess the biology of the renal mass and prevent therapy of benign lesions.

Veterinary Clinics: Tumor Ablation

Over the past decade, interventional oncology techniques have become integrated into the treatment plans of companion animals with cancer on a regular basis. Although procedures such as stenting are performed commonly, other less frequently utilized techniques for locoregional therapy, such as embolization and ablation, are emerging and demonstrating promise. Tumor ablation techniques are categorized into two subgroups: chemical ablation and energy-based ablation. Increased utilization of ablation will allow for the determination of specific indications and evaluation of outcomes for these techniques.

Radiofrequency ablation of small renal masses in comorbid patients

Introduction

Over the recent years, the progress in imaging techniques has led to increased detection of small renal masses (SRMs), including in elderly and high-risk patients. Partial nephrectomy (nephron-sparing surgery - NSS), the current standard of care in T1a kidney tumours, has some limitations in patients who are poor candidates for surgery, as it is associated with potential perioperative complications and possible renal function loss. Radiofrequency ablation (RFA), a minimally invasive method that can be performed percutaneously, is an option in such cases.

Aim

To present our experience in treatment of SRMs using RFA in comorbid patients.

Material and methods

In the years 2006-2012, 103 percutaneous, ultrasound-guided RFA procedures were performed in the Oncology Centre in Bydgoszcz in patients with an ASA score ≥ 3. Abdominal computed tomography and tumour biopsy were performed before the procedure. The average follow-up time was 46 months.

Results

The 1, 3 and 5-year overall survival rates were respectively 97%, 90% and 75%, while cancer-specific survival was 100%. No Clavien-Dindo grade ≥ 3 complications were observed.

Conclusions

Radiofrequency ablation performed percutaneously is a minimally invasive treatment and may be applied in patients who are, due to comorbidities, poor candidates for surgery. In comorbid patients, where other causes of death play an important role, the application of a minimally invasive treatment method with satisfactory oncological effectiveness is justified.

Radiofrequency Ablation for Renal Cancer in Von Hippel-Lindau Syndrome Patients: A Prospective Cohort Analysis

INTRODUCTION

Management of renal-cell carcinoma (RCC) in patients with Von Hippel-Lindau syndrome (VHL) represents a clinical dilemma: the oncologic outcomes must be weighed against preservation of renal function. Radiofrequency ablation (RFA) is currently used in selected cases for treatment of small-size RCC. The aim of this study was to evaluate the safety, complications, and functional and oncologic outcomes of RFA in the treatment of RCC in VHL patients.

PATIENTS AND METHODS

RCCs were treated with ultrasound-guided RFA or with laparoscopic RFA. Clinical and radiologic response, disease recurrence, and survival outcomes were evaluated during follow-up. Early and late complications were recorded and graded.

RESULTS

Nine RCC patients underwent RFA. The median number of RCCs per patient was 3 (interquartile range, 2-4). Among these 9 patients, a total of 20 RCCs were treated by RFA (19 ultrasound-guided RFA and 1 laparoscopic procedure). Median RCC size was 2.5 cm (interquartile range, 2.0-3.0). RFA did not impair renal function (P = .35). In 2 cases disease persisted, and in 1 case disease recurred after 18 months. These patients were retreated with ultrasound-guided RFA with complete response and no renal function impairment. RFA treatment was overall well tolerated and safe. No complications were recorded. Postoperative stay was no longer than 1 day.

CONCLUSION

RCC occurred in about two-thirds of VHL patients, who had young age at presentation; it was frequently multifocal and recurrent. The use of RFA, with extended indications, could represent a tailored treatment for VHL patients, reducing the risk of renal failure and resulting in satisfying oncologic results.

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

BACKGROUND

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

DISCUSSION

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

RESULTS

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

Ultrasound-guided hydrodissection for assisting percutaneous microwave ablation of renal cell carcinomas adjacent to intestinal tracts: a preliminary clinical study

PURPOSE

To evaluate the safety and efficacy of the clinical application of hydrodissection under ultrasound (US) guidance for assisting percutaneous microwave ablation (MWA) for the treatment of renal cell carcinomas (RCCs) adjacent to the intestinal tract.

MATERIALS AND METHODS

From April 2014 to December 2016, clinical data from 24 patients with 25 RCCs were retrospectively analysed. Percutaneous MWA under the assistance of US-guided hydrodissection were performed to treat RCCs with a mean maximal diameter of 3.80 ± 1.60 cm because the distance between the index tumour and the adjacent intestinal tracts were less than 0.5 cm on imaging. The separation success rate of the hydrodissection, technique efficacy rate of the MWA, local tumour progression (LTP), complications, and renal function including serum creatinine (Cr) and blood urea nitrogen (BUN) were assessed.

RESULTS

In total, 28 sessions of hydrodissection and MWA procedures were performed (one procedure in 22 patients and two procedures in 3 patients), and the separation success rate was 100% (28/28). The technique efficacy rate was 100% (25/25), and no LTP occurred. One patient exhibited a major complication (4.2%). Minor complications in 5 patients (20.8%) and side effects in 12 patients (50.0%) occurred. Compared with the pre-MWA levels, there were no significant differences in serum Cr and BUN 1-day post-MWA and at the last follow-up.

CONCLUSIONS

US-guided hydrodissection assistance for percutaneous MWA could be a safe and effective alternative for selected patients with RCCs adjacent to the intestinal tracts and can achieve good local tumour control and renal function preservation.

Complications of ultrasound-guided percutaneous microwave ablation of renal cell carcinoma

Purpose

To retrospectively review the complications of ultrasound (US)-guided percutaneous microwave ablation (MWA) of renal cell carcinoma.

Patients and methods

In this study, 101 patients with 105 tumors seen from April 2006 to Feb 2014 were enrolled retrospectively. The patients were treated with US-guided percutaneous MWA and were followed up with contrast-enhanced US and computed tomography or magnetic resonance imaging at 1, 3, and 6 months and every 6 months thereafter.

Results

Technical success was achieved in 99 of 105 tumors (94.3%). The median follow-up time was 25 (range 1.13–93.23) months. Among the 105 tumors, 26 complications in 24.8% of patients and 23 minor complications (Clavien–Dindo Grades I and II) in 21.9% of patients were noted, accounting for 88.5% of all complications. All the minor complications were cured. Three major complications (Clavien–Dindo Grade ≥III) occurred in 2.9% of the patients, accounting for 11.5% of all complications: hydrothorax in two patients and bowel injury in one. The two patients who had hydrothorax post-MWA had a history of cirrhosis and were treated with catheter drainage. The bowel injury was treated surgically. In all patients, the changes in serum creatinine and urea nitrogen levels from before to after the procedure were small.

Conclusion

US-guided percutaneous MWA is a beneficial treatment for renal cell carcinoma in selected patients; however, if the renal tumor is close to the bowel, or the patient has serious comorbidities or has undergone abdominal surgery, the procedure must be performed more carefully.

Evolutionary magnetic resonance appearance of renal cell carcinoma after percutaneous cryoablation

Objective:

To determine the evolutionary MRI appearance of renal cell carcinoma (RCC) following cryoablation.

Methods:

For this institution review board-approved study, we recruited patients with biopsy-proven RCC and treated them with percutaneous cryoablation between November 2009 and October 2014. Two radiologists retrospectively reviewed the pre-procedural and follow-up MRI. The findings included tumour sizes, signal intensities on T₁ weighted imaging (T1WI), T₂ weighted imaging (T2WI), diffusion-weighted imaging, apparent diffusion coefficient (ADC) map and contrast enhancement patterns. The ADC values of the tumours before and after treatment were measured.

Results:

A total of 26 patients were enrolled. The ablated tumours exhibited predominantly high signals on T1WI at 1–9-month follow-up (47.1% strong hyperintense at 3 months) and subsequently returned to being isointense. In T2WI, the signals of the ablated tumours were highly variable during the first 3 months and became strikingly hypointense after 6 months (58.3% strong hypointense at 6 months). Diffusion restriction was prominent during the first 3 months (lowest ADC: 0.62 ± 0.29 × 10⁻³ mm² s⁻¹ at 1 month). Contrast enhancement persisted up to 6 months after the procedure. The residual enhancement gradually increased in the dynamic scan and was most prominent in the delay phase.

Conclusion:

The MRI of the cryoablated renal tumour follows a typical evolutionary pattern.

Advances in knowledge:

Familiarity of practitioners with the normal post-cryoablation change of RCC on MRI can enable the early detection and prevention of tumour recurrence.

Use of cryoablation beyond the prostate

Cryoablation has been used for many years as a surgical ablation technique in the prostate and kidney. However, since the introduction of high-intensity focused ultrasound (HIFU) and robotic surgery for prostate tumours, its popularity in the urologic community has declined. In the early 2000s, innovations in cryoablation technology allowed the use of thinner probes, which were suitable for percutaneous application. As a result, radiologists began using cryoablation, first in the liver, and then in other organs or tissues such as the kidney, lung, breast, pancreas, bone, and soft tissue. In most of these locations, cryoablation has great potential given its inherent advantages, including the use of local anaesthesia, little or no pain during and after the procedure, real-time monitoring of the ablation area on US, CT or MRI, the potential for ablation of large tumours with multiple probes, and the ability to change the shape of the ablation in non-spherical tumours. Yet despite these advantages, the use of percutaneous cryoablation among radiologists appears to be far lower than that of heat-based ablation techniques. The aim of this article is to outline specific aspects of cryoablation and to illustrate its potential clinical applications with case presentations.

KEY POINTS

• Recent advances have made cryoablation suitable for percutaneous use by radiologists with image guidance. • Cryoablation has distinct advantages over heat-based ablation techniques. • Cryoablation is becoming increasingly popular for lung, breast, kidney, bone, and soft tissue tumours.

[Percutaneous radiofrequency ablation of renal tumors: update 2015]

BACKGROUND

Stage I renal cell carcinoma is a malignancy with a relatively good prognosis. The incidence of all renal cell carcinomas is approximately 9/100,000 persons. There are nearly 15,000 newly diagnosed patients every year (men twice as often as women).

TREND

In the last decade, a trend away from radical open resection towards nephron-sparing approaches has been observed. Currently, partial nephrectomy is the surgical gold standard for the treatment of small renal tumors. However, excellent clinical results are obtained using percutaneous radiofrequency ablation (RFA): low complication rates and preservation of the renal function.

RESULTS

Primary and secondary technical success rates are 69-100% and 90-100%, respectively. In large series, major complication rates of RFA of 0-14% are reported. A relevant deterioration of renal function after RFA is very rare. The 5-year local recurrence-free survival rates, metastasis-free survival rates, cancer-specific survival rates, and overall survival rates are 88-93, 95-100, 98-100, and 58.3-85%, respectively. In this context, the lack of appropriate long-term data is often cited as a limitation.

CONCLUSION

Different meta-analyses come to the conclusion that in case of adequate tumor and patient selection RFA shows oncologic results comparable with surgical resection. Accepted indications for RFA are T1 renal tumors in patients with advanced age, significant comorbidities, reduced renal function, single kidney, and/or no wish for operation. Predictors for the success include tumor size and location as well as operator experience. To define the real efficacy of RFA in the treatment of renal tumors, randomized controlled clinical long-term studies are indicated.

Renal Ablation Techniques: State of the Art

OBJECTIVE

The purpose of this article is to describe the indications for and approach to image-guided percutaneous ablation of renal tumors.

CONCLUSION

Image-guided ablation techniques have become accepted treatment of patients with small renal tumors, a viable alternative to partial nephrectomy.

Thermal Ablation of Renal Tumors: Indications, Techniques and Results

BACKGROUND

About 15,000 persons receive the diagnosis of kidney cancer in Germany every year. Surgical resection is the standard treatment for locally confined tumors, but minimally invasive thermoablative techniques are increasingly being used as well.

METHODS

This article is based on publications retrieved by a selective literature search in PubMed regarding the thermoablative techniques now used in clinical practice, with particular attention to radiofrequency ablation (RFA) and cryoablation (CA).

RESULTS

RFA and CA are suitable for patients who cannot undergo surgery because of comorbid illnesses or who have contralateral recurrences or a hereditary precancerous condition. The primary technical success rate of these procedures ranges from 88% to 100%. More than 95% of tumors under 3 cm in diameter can be completely ablated. Reported complication rates range from 1% to 7%. New data on long-term outcomes reveal metastasis-free survival rates of 88% to 99% five years after ablation. A major advantage of these procedures is that thermoablation does not impair renal function to any relevant extent and is thus a good option for patients with limited renal function or a single kidney.

CONCLUSION

The thermoablative techniques are an important addition to the armamentarium of effective treatments for locally confined renal tumors. The guidelines of the American and European urological societies now list thermoablation with RFA or CA as an option for the treatment of small renal tumors with curative intent. Thermoablation of renal tumors has not yet been studied in randomized controlled trials; these will be needed so that the efficacy of tumor control, survival rates, complication rates, and quality of life after treatment can be reliably evaluated to provide definitive confirmation of the value of interstitial techniques.

Image-guided percutaneous renal cryoablation for stage 1 renal cell carcinoma with high surgical risk

BACKGROUND

This study was undertaken to evaluate the feasibility, safety, and therapeutic effects of percutaneous renal cryoablation under local anesthesia with conscious sedation for patients who have unresectable stage 1 (T1NoMo) renal cell carcinoma (RCC) in high surgical risk.

METHODS

Eighteen patients who were not candidates for surgery underwent primary cryosurgery guided by gray-scale ultrasound. Contrast-enhanced ultrasonography (CEUS) and contrast-enhanced computed tomography (CT) were performed to evaluate treatment at completion.

RESULTS

The mean follow-up period was 26.8 months (range, 12-56 months). All tumors were biopsied before cryosurgery. Seventeen tumors remained free of enhancement during follow-up period. No major complications associated with cryoablation procedures were found though two instances of subcapsular hematomas, one of retroperitoneal errhysis and one of nausea, were seen after cryoablation. One patient had a local recurrence of tumor and received additional cryoablation. Local tumor control rate was 100 % of T1NoMo tumors including the recurrence case who underwent additional cryoablation.

CONCLUSIONS

Percutaneous cryoablation can be recommended as a feasible, safe, and promising therapy for the treatment of renal tumor, especially those unresectable stage 1 RCC, with a low risk of complications.

Comparative Outcome of Computed Tomography-guided Percutaneous Radiofrequency Ablation, Partial Nephrectomy or Radical Nephrectomy in the Treatment of Stage T1 Renal Cell Carcinoma

Renal cell carcinoma (RCC) accounts for 3% of all cancers in adults. The indications for Radiofrequency Ablation (RFA) for renal carcinomas include T1a (tumor 4 cm or less, limited to the kidney), elderly patients, renal impairment, comorbidities, poor surgical candidate, and multiple bilateral renal masses. We retrospectively reviewed medical records, specifically investigating the indications, complications and outcomes of RFA and nephrectomy for treatment of RCC in a tertiary medical center with a predominantly Hispanic patient population. Forty-nine patients with RCC were evaluated. Nine patients had RFA, 9 had partial nephrectomy and 31 had radical nephrectomy. All patients among the 3 groups had stage T1N0M0 RCC at diagnosis. Tumor recurrence was observed in 2 (22%) patients that had RFA, one (11%) patient that had partial nephrectomy and no patients that had radical nephrectomy. One patient had recurrence of the tumor at the opposite kidney pole from the initial RFA site 4 years later. This particular patient did not have any tumor recurrence at the site of the initial RFA. A second RFA was performed on the recurrent tumor with no recurrence upon subsequent follow up visits. The second patient had recurrence of the RCC on 1 year follow that was discovered to be sarcomatoid RCC, which is an aggressive type with a poor prognosis. Our results support the clinical utility of RFA in patients with stage T1 RCC who are poor surgical candidates or those with reduced renal function. The clinical utility of RFA as an equally effective approach when compared to partial nephrectomy in patients with stage T1 RCC that meet strict indications for the procedure. The treatment choice should be individualized and based on the characteristics of the renal tumor such as size, location and histological type of RCC. We conclude that RFA presents a safe treatment choice for patients with RCC if long term follow up is maintained.