Complications of image-guided radiofrequency ablation of renal cell carcinoma: causes, imaging features and prevention methods

Radiation Therapy in the Treatment of Localized and Advanced Renal Cancer

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

Management of renal cell carcinoma in transplant kidney: a systematic review and meta-analysis

INTRODUCTION

After transplantation, approximately 10% of renal cell carcinomas are detected in graft kidneys. These tumors (gRCC) present surgeons with the difficulty of finding a treatment that guarantees both oncological clearance and maintenance of function. We conducted a systematic review and an individual patient data meta-analysis on the oncology, safety and functional outcomes of the available treatments for gRCC.

EVIDENCE ACQUISITION

A systematic search was performed across MEDLINE, EMBASE, and Web of Science including any study reporting perioperative, functional and survival outcomes for patients undergoing graft nephrectomy (GN), partial nephrectomy (PN) or thermal ablation (TA) for gRCC. Quade's ANCOVA, Spearman Rho and Pearson χ², Kaplan-Meier, Log-rank and Standard Cox regression and other tests were used to compare treatments. Studies' quality was evaluated using a modified version of Newcastle Ottawa Scale.

EVIDENCE SYNTHESIS

A number of 29 studies (357 patients) were included. No differences between TA and PN were found in terms of safety, functional and oncological outcomes for T1a gRCCs. When applied to pT1b gRCC, PN showed no difference in complications, progression or cancer-specific deaths compared to smaller lesions; PN validity for pT2 gRCCs should be considered unverified due to lack of sufficient evidence. The efficacy and safety of PN or TA for multiple gRCC remain controversial. In case of non-functioning, large (T≥2), complicated or metastatic gRCCs, GN appears to be the most reasonable choice. Quality of evidence ranged from very low to moderate. Studies with large cohorts and longer follow-up are still needed to clarify oncological and functional differences.

CONCLUSIONS

PN and TA might be offered as a nephron-sparing treatment in patients with T1a gRCC. There is no significant difference between these options and GN in terms of oncological outcomes and complications. PN and TA offer similar functional outcomes and graft preservation. PN for T1b gRCC seems feasible and safe, but its validity should be considered unverified.

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.

MRI and CT in the follow-up after irreversible electroporation of small renal masses

PURPOSE

Ablation plays a growing role in the treatment of small renal masses (SRMs) due to its nephron sparing properties and low invasiveness. Irreversible electroporation (IRE) has the potential, although still experimental, to overcome current limitations of thermal ablation. No prospective imaging studies exist of the ablation zone in the follow up after renal IRE in humans. Objectives are to assess computed tomography (CT) and magnetic resonance imaging (MRI) on the ablation zone volume (AZV), enhancement and imaging characteristics after renal IRE.

METHODS

Prospective phase 2 study of IRE in nine patients with ten SRMs. MRI imaging was performed pre-IRE, 1 week, 3 months, 6 months and 12 months after IRE. CT was performed pre-IRE, perioperatively (direct after ablation), 3 months, 6 months and 12 months after IRE. AZVs were assessed by two independent observers. Observer variation was analyzed. Evolution of AZVs, and relation between the needle configuration volume (NCV; planned AZV) and CT- and MRI volumes were evaluated.

RESULTS

Eight SRMs were clear cell renal cell carcinomas, one SRM was a papillary renal cell carcinoma and one patient had a non-diagnostic biopsy. On CT, median AZV increased perioperatively until 3 months post-IRE (respectively, 16.8 cm3 and 6.2 cm3) compared to the NCV (4.8 cm3). On MRI, median AZV increased 1-week post-IRE until 3 months post-IRE (respectively, 14.5 cm3 and 4.6 cm3) compared to the NCV (4.8 cm3). At 6 months the AZV starts decreasing (CT 4.8 cm3; MRI 3.0 cm3), continuing at 12 months (CT 4.2 cm3, MRI 1.1 cm3). Strong correlation was demonstrated between the planning and the post-treatment volumes. Inter-observer agreement between observers was excellent (CT 95% CI 0.82-0.95, MRI 95% CI 0.86-0.96). All SRMs appeared non-enhanced immediately after ablation, except for one residual tumour. Subtraction images confirmed non-enhancement on MRI in unclear enhancement cases (3/9). Directly after IRE, gas bubbles, perinephric stranding and edema were observed in all cases.

CONCLUSION

The AZV increases immediately on CT until 3 months after IRE. On MRI, the AZV increases at 1 week until 3 months post-IRE. At 6 months the AZV starts decreasing until 12 months post-IRE on both CT and MRI. Enhancement was absent post-IRE, except for one residual tumour. Gas bubbles, perinephric stranding and edema are normal findings directly post-IRE.

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.

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.

Imaging of acute abdomen in cancer patients

The pattern of disease causing acute abdominal pain has changed over last few decades, some of this has been attributed to intraabdominal cancers. The most common acute abdominal complaints in cancer patients are related to the gastrointestinal system. Abdominal emergencies in cancer patients can result from the underlying malignancy itself, cancer therapy and/or result from the standard pathologies causing acute abdomen in otherwise healthy population. Therapy-related or disease-related immunosuppression or high dose analgesics often blunt many of the findings which are usually expected in non-cancer general population. This complicates the clinical picture rendering the clinical exam less reliable in many cancer patients, and resulting in different pathologies which clinicians and the radiologists should remain aware of. This article focuses on imaging illustrations with differential diagnosis for various emergency scenarios related to acute abdomen specifically in oncologic settings.

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.

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.

Image-Guided Renal Interventions

Image-guided renal biopsies have an increasing role in clinical practice. Renal mass and renal parenchymal biopsy indications, techniques, and other clinical considerations are reviewed in this article. Image-guided renal mass ablation shows significant promise and increasing clinical usefulness as more studies demonstrate its safety and efficacy. Renal mass ablation indications, techniques, and other considerations are also reviewed.

Low-dose CT protocols for guiding radiofrequency ablation for the treatment of small renal cell carcinomas

OBJECTIVE

Computed tomography (CT)-guided radiofrequency ablation (RFA) results in a high radiation dose. This study aimed to assess low-dose CT protocols for guiding RFA and oncologic outcomes for the treatment of small renal cell carcinoma (RCC).

MATERIALS AND METHODS

Between December 2011 and December 2014, CT-guided RFA was performed in 31 patients with 31 biopsy-proven RCCs (median, 2.1 cm). RFA included planning, targeting, monitoring and survey phases. The dose length product (DLP), CT dose index volume (CTDIvol), effective dose, number of scans, scan range, tube current and exposure time of RFA phases were compared. The 3-year recurrence-free survival rate was recorded. Nonparametric or parametric repeated-measures ANOVA with Dunn's or Tukey-Kramer multiple comparisons and Kaplan-Meier analysis were used for statistical analysis.

RESULTS

The median total DLP, CTDIvol and effective dose of CT-guided RFA procedures per session were 1238.8 mGy (range 517.4-3391.7 mGy), 259.7 mGy (10.7-67.9 mGy) and 18.6 mSv (7.8-50.9 mSv), respectively. The median DLP, CTDIvol, effective dose, number of scans, tube current and exposure time during the targeting phase were higher than those during the other phases (p < 0.001). The scan range in the targeting phase was the same as that in the monitoring phase (p > 0.05) but smaller than those in the planning and survey phases (p < 0.001). The 3-year recurrence-free survival rate was 96.7%.

CONCLUSIONS

Low-dose CT protocols for guiding RFA may reduce radiation dose without compromising oncologic outcomes. Reducing the number of scans during the targeting phase contributes to dose reduction.

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.

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.

CT-Guided Radiofrequency Ablation of T1a Renal Cell Carcinoma in Korea: Mid-Term Outcomes

Objective

To evaluate the mid-term outcomes of percutaneous radiofrequency ablation (RFA) treatment in patients with small (< 4 cm) renal cell carcinoma (RCC) in Korea.

Materials and Methods

Between 2010 and 2015, 51 patients (40 men and 11 women; median age, 57 years) with biopsyproven 51 RCC were treated using CT-guided RFA. All patients were clinically staged T1aN0M0 prior to RFA. The median tumor size and follow-up period were 2.1 cm (range, 1.0–3.9 cm) and 26 months (4–60 months), respectively. Local tumor progression, distant metastasis, primary and secondary effectiveness rates, and major complication rates were recorded. Estimated glomerular filtration rates (GFRs) between pre-RFA and last follow-up were compared using paired t tests. The 2-year recurrence-free survival rate was calculated using Kaplan-Meier survival analysis.

Results

Of the 51 patients, 2 (3.9%) experienced local tumor progression, and 1 (2.0%) had lymph node metastasis after the first RFA session. Primary and secondary effectiveness rates were 96.1% (49/51) and 100% (1/1), respectively. Only 1 patient experienced a major complication (uretero-pelvic stricture) after the second RFA session for treating a local tumor progression, and the major complication rate was 1.9% (1/52). The median pre-RFA and last follow-up GFRs were 87.1 mL/ min/1.73 m² (14.2–142.7 mL/min/1.73 m²) and 72.0 mL/min/1.73 m² (7.2–112.6 mL/min/1.73 m²), respectively (p < 0.0001). The 2-year recurrence-free survival rate was 96.0%.

Conclusion

CT-guided RFA is a safe and effective treatment in Korean patients with T1a RCC because of excellent mid-term outcomes.

Percutaneous radiofrequency ablation of a bleeding pseudoaneurysm during CT-guided renal cancer treatment. A case report

We describe a new emergency interventional radiology approach in percutaneous procedure complications. We present the case of an 81-year-old male with small renal cancer, approached with percutaneous radiofrequency ablation (RTA) and complicated by pseudoaneurysm bleeding of a renal artery branch. In the emergency setting, pseudoaneurysm was treated in the CT room by the same RTA needle, without any complications or local tumor recurrence during the next 6-month follow-up.

Effect of Stereotactic Body Radiotherapy on the Growth Kinetics and Enhancement Pattern of Primary Renal Tumors

OBJECTIVE

The objective of our study was to assess the growth rate and enhancement of renal masses before and after treatment with stereotactic body radiotherapy (SBRT).

MATERIALS AND METHODS

This retrospective study included all patients with renal masses who underwent SBRT during a 5-year period. Orthogonal measurements of renal masses were obtained on pre- and posttreatment CT or MRI. Pre- and posttreatment growth rates were compared for renal mass diameter and volume using the t test. Pre- and posttreatment tumor enhancement values were compared for tumors that underwent multiphasic contrast-enhanced MRI.

RESULTS

Forty patients underwent SBRT for the treatment of 41 renal tumors: clear cell renal cell carcinomas (RCCs) (n = 16), papillary RCCs (n = 6), oncocytic neoplasms (n = 8), unclassified RCCs (n = 2), urothelial carcinoma (n = 1), and no pathologic diagnosis (n = 8). The mean maximum tumor diameter before treatment was 3.9 cm (range, 1.6-8.3 cm). Three hundred thirty-eight pre- and posttreatment imaging studies were analyzed: 214 MRI studies and 124 CT studies. The mean pre- and posttreatment lengths of observation were 416 days (range, 2-1800 days) and 561 days (83-1366 days), respectively. The mean pretreatment tumor growth rate of 0.68 cm/y decreased to -0.37 cm/y post treatment (p < 0.0001), and the mean tumor volume growth rate of 21.2 cm(3)/y before treatment decreased to -5.35 cm(3)/y after treatment (p = 0.002). Local control-defined as less than 5 mm of growth-was achieved in 38 of 41 (92.7%) tumors. The Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 showed progression in one tumor (2.4%), stability in 31 tumors (75.6%), partial response in eight tumors (19.5%), and complete response in one tumor (2.4%). No statistically significant change in tumor enhancement was shown (mean follow-up, 142 days; range, 7-581 days).

CONCLUSION

Renal tumors treated with SBRT show statistically significant reductions in growth rate and tumor size after treatment but do not show statistically significant differences in enhancement in the initial (mean, 142 days) posttreatment period.

Interventional oncology: pictorial review of post-ablation imaging of liver and renal tumors

Percutaneous image-guided ablation is now commonly performed in many institutions for the treatment of hepatocellular carcinoma, liver metastases, and renal cell carcinoma in select patients. Accurate interpretation of post-ablation imaging is of supreme importance because treatment algorithms for these diseases rely heavily on imaging to guide management decisions. The purpose of this pictorial essay is to provide abdominal imagers with a review of the indications for percutaneous ablation in the abdomen, a basic overview of ablation modalities in clinical use today, the expected post-ablation imaging findings in the liver and kidney, and potential complications of hepatic and renal ablation procedures.

Percutaneous radiofrequency ablation of sporadic Bosniak III or IV lesions: treatment techniques and short-term outcomes

PURPOSE

To evaluate retrospectively the techniques and outcomes of percutaneous radiofrequency (RF) ablation for treatment of Bosniak III or IV lesions.

MATERIALS AND METHODS

Between August 2006 and August 2013, 30 patients (25 men and 5 women; mean age, 57 y; range, 22-77 y) with 35 nonhereditary Bosniak III (n = 15) or IV (n = 20) lesions underwent computed tomography-guided RF ablation. The mean size of the lesions was 2.8 cm ± 0.9 (range, 1.1-4.3 cm). The mean follow-up period was 24 months ± 16 (range, 6-70 mo). Duration of ablation, number of sessions and electrode repositions, primary and secondary effectiveness rates, major complication rate, reduction rate of lesion size, estimated glomerular filtration rate (GFR), and local tumor progression were recorded. Wilcoxon signed rank test was used for statistical analysis.

RESULTS

Mean duration of ablation was 18 minutes ± 14 (range, 2-65 min), and median number of sessions was one. Median number of electrode repositions was 1.0 ± 1.6 (range, 0-6). Primary and secondary effectiveness rates were 97.1% (34 of 35) and 100% (1 of 1), respectively. Mean reduction rate of lesion size was significantly greater from before RF ablation to 1 month after RF ablation (7.1 mm/mo ± 4.5) compared with from 1 month after RF ablation to the last month of follow-up (0.2 mm/mo ± 0.2; P < .0001). Mean GFR after RF ablation (65.4 mL/min/1.73 m(2) ± 26.1) was minimally reduced but significantly different from mean GFR before RF ablation (76.0 mL/min/1.73 m(2) ± 28.4; P < .0001). Major complications occurred in 2 of 35 RF ablation sessions for a rate of 5.7%, resulting from pneumothorax. Of 30 patients, 29 (96.7%) did not have local tumor progression or metastasis for 2 years.

CONCLUSIONS

Percutaneous RF ablation is technically feasible and yields excellent short-term outcomes in treating sporadic Bosniak III or IV lesions.

A propensity-matched comparison of perioperative complications and of chronic kidney disease between robot-assisted laparoscopic partial nephrectomy and radiofrequency ablative therapy

OBJECTIVE

The study presents a matched-pair analysis of robot-assisted laparoscopic partial nephrectomy (RALPN) versus radiofrequency ablation (RFA) to compare the perioperative incidence of complications and chronic kidney disease (CKD).

METHODS

All 46 RFA and 206 RALPN cases from June 2005 to December 2011 were retrospectively reviewed from the medical records and were matched 1:1 based on propensity scores by sex, tumor size, tumor laterality of kidney, tumor location within the kidney, and clinical T stage. Hilar vessel clamping was performed in all RALPN patients. The estimated glomerular filtration rate was used to define the CKD of < 60 mL/minute/1.73 m(2) by the Modification of Diet in Renal Disease equation. All patients with baseline CKD or solitary kidney were excluded prior to the matching analysis. The complication was noted with modified Clavien grades ≥ 3. Statistical analysis was performed to compare the perioperative incidence of complications and CKD.

RESULTS

A total of 27 matched pairs of RFA and RALPN patients were enrolled for analyzing CKD and perioperative complications. The better general conditions, higher estimated blood loss and transfusion rates, and longer operative time and hospital stay were observed significantly in RALPN patients (p < 0.05). Matched analysis demonstrated that the incidences of both perioperative complications (p = 0.434) and of CKD (p = 0.500) were not significantly different. No complication higher than Grade 4 was detected in either group.

CONCLUSION

Despite the intraoperative renal ischemia and invasiveness of the procedure associated with RALPN, the incidence of perioperative complication and of CKD developing rates were statistically similar.

Complications of image-guided thermal ablation of liver and kidney neoplasms

Image-guided thermal ablation is a widely accepted tool in the treatment of a variety of solid organ neoplasms. Among the different techniques of ablation, radiofrequency ablation, cryoablation, and microwave ablation have been most commonly used and investigated in the treatment of liver and kidney neoplasms. This article will review complications following thermal ablation of tumors in the liver and kidney, and discuss the risks and clinical presentation of each complication as well as how to treat and potentially avoid complications.

Radiofrequency thermal ablation of renal tumors

Percutaneous radiofrequency ablation (PRFA) of renal malignancies is currently a therapeutic option for patients who are not able to undergo surgery. Some authors consider PRFA as the therapeutic standard in the treatment of renal neoplasms in non-operable patients due to comorbid conditions and in patients with mild-moderate renal failure, to preserve residual renal functionality. The use of PRFA has become more and more widespread due to a rise in the incidental detection of renal cell carcinomas with the ever-increasing use of Imaging for the study of abdominal diseases. Clinical studies indicate that RF ablation is an effective therapy with a low level of risk of complications, which provides good results in selected patients over short and medium term periods of time, however up to now few long-term studies have been carried out which can confirm the effectiveness of PRFA.

Percutaneous ablation for small renal masses-complications

Although percutaneous ablation of small renal masses is generally safe, interventional radiologists should be aware of the various complications that may arise from the procedure. Renal hemorrhage is the most common significant complication. Additional less common but serious complications include injury to or stenosis of the ureter or ureteropelvic junction, infection/abscess, sensory or motor nerve injury, pneumothorax, needle tract seeding, and skin burn. Most complications may be treated conservatively or with minimal therapy. Several techniques are available to minimize the risk of these complications, and patients should be appropriately monitored for early detection of complications. In the event of a serious complication, prompt treatment should be provided. This article reviews the most common and most important complications associated with percutaneous ablation of small renal masses.

Percutaneous ablation for small renal masses-imaging follow-up

Image-guided percutaneous thermal ablation is a safe and effective nephron-sparing alternative to surgical resection for the treatment of small renal tumors. Assessment of treatment efficacy relies heavily on interval follow-up imaging after treatment. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) both play a pivotal role in evaluating the treatment zone, identifying residual tumor, and detecting early and delayed procedure-related complications. This article discusses a surveillance imaging protocol for patients who undergo percutaneous thermal ablation of renal tumors, and also illustrates the typical appearances of both successfully treated tumors and residual disease on contrast-enhanced CT or MRI. In addition, it discusses the imaging appearance of potential early and delayed treatment-related complications to facilitate their prompt detection and management.

Analysis of radiofrequency ablation of small renal tumors in patients at high anesthetic and surgical risk: urologist experience with follow-up results in the initial six months

BACKGROUND

To evaluate the results of various types of radiofrequency ablation (RFA) treatment of renal tumors in patients with excessive anesthetic and surgical risk.

MATERIALS AND METHODS

Data for RFA performed in in high risk patients were retrospectively evaluated. Other RFA applications in patients with no anesthetic and/or surgical risk were excluded. RFA was by ultrasound or CT guided percutaneous (USG/CT-PRFA) and retroperitoneally or transperitoneally laparoscopic (R/T-LRFA) techniques under general or local anethesia. Follow-up data of enhanced CT or MRI after 1, 3 and 6 months were analysed for twelve RFA applications.

RESULTS

The RFA applications included 4 (40%) left-sided, 5 (50%) right-sided and 1 (10%) bilaterally RFA (simultaneously 1 right and 2 left). The localizations of tumors were 2 (16.6%) upper, 5 (41.6%) mid and 5 (41.6%) lower pole. The RFA applications included 9 (75%) USG-PRFA, 1 (8.3%) CT-PRFA, 1 (8.3%) T-LRFA and 1 (8.3%) R-LRFA. The mean age was 65.3 ± 8.5 (52-76) years. The mean tumor size was 29.6 ± 6.08 (15-40) mm. No complications related to the RFA were encountered in any of the cases. Failure (residual tumour) was determined in 8.3% (1/12) of USG-RFA application. The success rate was thus 91.7% (11/12). Other 1st, 3rd and 6th months follow-up data revealed no residua and recurrence.

CONCLUSIONS

RFA application appears to be safe as a less invasive and effective treatment modality in selected cases of small renal tumors in individuals with excessive anesthetic and also surgical risk.

Comparison of laparoscopic radiofrequency ablation and open partial nephrectomy in patients with a small renal mass

Purpose

We have performed both open partial nephrectomy (OPN) and laparoscopic radiofrequency ablation (RFA) on selected patients since January 2007 and have been following these patients through serial laboratory assessments and computed tomography (CT). The purpose of the present study was to evaluate long-term oncologic outcomes and renal function status for laparoscopic RFA versus OPN at a minimum follow-up of 3 years.

Materials and Methods

A total of 55 patients with exophytic, single small renal masses were treated with either OPN (n=14) or laparoscopic RFA (n=41) by a single surgeon. The indications for laparoscopic RFA were as follows: 1) cases with the greatest dimension of the renal mass <3 cm, and 2) cases in which the collecting system, renal calyx, and great vessels were free from the tumor margins by 1 cm.

Results

The estimated blood loss (EBL), the operation time, and the mean number of hospital days was significantly lower in the laparoscopic RFA group than in the OPN group. Oncologic data did not differ significantly between the two groups. Creatine clearance levels did not differ significantly compared with those before the operation in either group.

Conclusions

Our data suggest excellent therapeutic outcomes with laparoscopic RFA with achievement of effective operative times, hospital stays, and EBL compared with OPN. According to our indications for laparoscopic RFA, laparoscopic RFA is an effective minimally invasive therapy for the treatment of small renal masses, yielding oncologic outcomes and renal function equivalent to those of OPN.

Radiofrequency ablation of spine: an experimental study in an ex vivo bovine and in vivo swine model for feasibility in spine tumor

STUDY DESIGN

An experimental study of radiofrequency ablation (RFA) of spine in an ex vivo bovine and in vivo swine animal model.

OBJECTIVE

To study the feasibility of RFA for spine tumors close to the spinal cord, to examine the safety and efficacy of RFA, and to suggest quantitative guidelines for clinical application.

SUMMARY OF BACKGROUND DATA

RFA has received increased attention as an effective and minimally invasive method for treating soft tissue tumors. However, there is currently only anecdotal evidence to support RFA of spinal tumors and only a few experimental studies have been conducted.

METHODS

We performed ex vivo experiments by producing 10 RFA zones in extracted bovine spines and an in vivo study by producing 8 RFA zones in a swine spine using internally cooled electrodes. The volume and diameter of ablation zones were evaluated and analyzed by the corresponding energy and ablation times.

RESULTS

In the ex vivo study, the average diameters of the ablation zones were 3.05 cm, 1.85 cm, and 1.26 cm, for the D1, D2, and D3 zones, respectively, and the average ablation volume was 4.19 cm. In the in vivo study, the average diameters were 2.51 cm, 2.05 cm, and 1.28 cm, respectively, and the ablation volume was 6.80 cm. The ablation zones demonstrated a positive correlation with ablation time, but the coefficients were 0.942 ex vivo and 0.257 in vivo. The temperature in the ex vivo study was inversely proportional to distance, with a maximal temperature of 63.7°C at 10 mm; however, the maximum temperature was 38.2°C in the in vivo study.

CONCLUSION

This study demonstrated that sufficient RFA zone volume could be induced, which suggests that RFA is feasible and safe for application to human spinal tumors with predictability.

LEVEL OF EVIDENCE

N/A.

Percutaneous radiofrequency ablation of small renal tumours in patients with a single functioning kidney: long-term results

OBJECTIVES

To evaluate the long-term results of percutaneous radiofrequency ablation (RFA) of small renal tumours in patients with a single functioning kidney (SFK).

METHODS

This is a single-centre prospective study. Patients with an SFK and a tumour smaller than 3.5 cm, treated with RFA over a 7.5-year period, were included. Nineteen consecutive patients (12 male), aged between 33 and 83 years (mean 61.4), were treated for 23 lesions. Primary endpoints were technical success and tumour recurrence rate. Secondary endpoints were the deterioration of renal function and overall survival rate.

RESULTS

The mean follow-up was 56.1 months (range 36-102). Primary technical success was 100 %. There were no major peri-procedural complications. In two cases, minor complications occurred. There was no significant difference between the baseline glomerular filtration rate (GFR) and GFR at 3, 12 and 24 months post-procedure. In four lesions (17 %), recurrence was detected and an additional RFA session was performed. None of the patients developed renal failure during their lifetime. Three of the patients died because of other reasons.

CONCLUSIONS

Percutaneous RFA of small renal tumours in patients with an SFK offers very satisfactory long-term results regarding preservation of renal function, local tumour control and overall survival.

KEY POINTS

• Tumour in a single functioning kidney requires minimally invasive treatment. • Radiofrequency ablation plays an established role in managing small renal tumours. • Long-term results of radiofrequency ablation have shown satisfactory local tumour control. • Long-term results have also shown that renal function may be preserved.

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease: indications, techniques, complications, and outcomes

Renal cell carcinoma (RCC) in patients with von Hippel Lindau (VHL) disease tends to be multifocal, bilateral, and recur or develop new tumors after removal. These characteristics make treating hereditary RCCs difficult for urologists or radiologists compared to treating a sporadic RCC. Radiofrequency ablation (RFA) is a minimally-invasive treatment for small hereditary RCCs associated with a low complication rate and a minimal decrease in renal function. No RFA guidelines have been established about what to treat and when and how to ablate RCCs in patients with VHL disease. Besides, reports on complications and treatment outcomes in this patient group are rare. The purpose of this review is to discuss the indications, techniques, complications, and outcomes of RFA in treating RCC in patients with VHL disease.

Solid renal masses: effectiveness and safety of image-guided percutaneous radiofrequency ablation

With increasing emphasis on minimally invasive nephron-sparing techniques for treatment of renal tumors, image-guided percutaneous radiofrequency ablation (RFA) has emerged as a safe and effective method of tumor eradication that may be performed on an outpatient basis, with relatively low morbidity and mortality. This review addresses the clinical and technical considerations, risks, complications, and currently reported efficacy data pertaining to RFA of renal tumors, as well as the standardized approach to treatment and follow-up currently used in our practice.

Thermal ablation in renal cell carcinoma: what affects renal function?

Because of its minimally invasive nature, thermal ablation is increasingly performed in patients with renal cell carcinoma (RCC) who are poor surgical candidates. Thermal ablation has been associated with excellent outcomes, and thus has been regarded as a viable alternative to nephron-sparing surgery. Many papers report minimal to no reduction in renal function after ablation therapies. However, in order to achieve good local control, normal renal tissue must be sacrificed, subsequently leading to reduced renal function. The amount of normal renal tissue to be ablated depends on the size, location, and number of RCCs, as well as the type of thermal ablation applied. However, there are few reports about what reduces renal function following thermal ablation therapies. The purpose of this review was to discuss factors that affect reduction in renal function and to assess the relationship between local tumour control and renal function.

Ablative therapies for renal tumors

Owing to an increased use of diagnostic imaging for evaluating patients with other abdominal conditions, incidentally discovered kidney masses now account for a majority of renal tumors. Renal ablative therapy is assuming a more important role in patients with borderline renal impairment. Renal ablation uses heat or cold to bring about cell death. Radiofrequency ablation and cryoablation are two such procedures, and 5-year results are now emerging from both modalities. Renal biopsy at the time of ablation is extremely important in order to establish tissue diagnosis. Real-time temperature monitoring at the time of radiofrequency ablation is very useful to ensure adequacy of ablation.

Complications following 573 percutaneous renal radiofrequency and cryoablation procedures

PURPOSE

To review complications related to percutaneous renal tumor ablation.

MATERIALS AND METHODS

Prospectively collected data related to renal radiofrequency (RF) ablation and cryoablation procedures performed from May 2000 through November 2010 were reviewed. This included 573 renal ablation procedures performed in 533 patients to treat 633 tumors. A total of 254 RF ablation and 311 cryoablation procedures were performed; eight patients underwent simultaneous RF ablation and cryoablation. The mean age of patients at the time of the procedure was 70 years (range, 24-93 y), and 382 of 573 procedures (67%) were performed in male patients. Complications were recorded according to the Clavien-Dindo classification scheme. Duration of hospitalization was also documented.

RESULTS

Of the 573 procedures, 63 produced complications (11.0% overall complication rate). There were 66 reported complications, of which 38 (6.6% of total procedures) were Clavien-Dindo grade II-IV major complications; there were no deaths. Major complication rates did not differ statistically (P = .15) between cryoablation (7.7%; 24 of 311) and RF ablation (4.7%; 12 of 254). Of the complications related to cryoablation, bleeding and hematuria were most common. Bleeding during cryoablation was associated with advanced age, increased tumor size, increased number of cryoprobes, and central position (P < .05). Of those treated with RF ablation, nerve and urothelial injury were most common. Mean hospitalization duration was 1 day for RF ablation and cryoablation.

CONCLUSIONS

Complications related to percutaneous renal ablation are infrequent. Recognition of potential complications and associated risk factors can allow optimization of periprocedural care.

Percutaneous radiofrequency ablation of a small renal mass complicated by appendiceal perforation

Percutaneous radiofrequency ablation (RFA) has gained wide acceptance as nephron-sparing therapy for small renal masses in select patients. Generally, it is a safe procedure with minor morbidity and acceptable short-term oncologic outcome. However, as a result of the close proximity of vital structures, such as the bowel, ureter, and large vessels, to the ablative field, complications regarding these structures may occur. This is the first article describing appendiceal perforation as a complication of computed tomography-guided RFA despite hydrodissection. When performing this innovative and promising procedure one should be aware of the possibility of particular minor and even major complications.

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease previously undergoing a radical nephrectomy or repeated nephron-sparing surgery

BACKGROUND

Radiofrequency ablation (RFA) is accepted as a minimally invasive treatment of renal cell carcinoma (RCC). However, RFA is not fully evaluated for treating RCC in patients with von Hippel Lindau (VHL) disease who cannot undergo surgery due to serious postoperative morbidity or mortality.

PURPOSE

To evaluate the role of RFA of RCC in patients with VHL disease previously undergoing renal surgery.

MATERIAL AND METHODS

Percutaneous RFA was performed for treating 14 RCCs in six patients who had undergone radical nephrectomy (n = 3) or repeated nephron-sparing surgery (n = 3). Treatment feasibility, complications, outcome, and the change of renal function were evaluated.

RESULTS

To completely ablate 14 RCCs, 23 ablations during 12 sessions were necessary. Of 14 RCCs, nine were in proximity (<5 mm) to one or more following organs: bowel (n = 4), ureteropelvic junction or pelvis (n = 2), psoas muscle (n = 2), vascular pedicle (n = 1), and pancreas (n = 1). Of 12 sessions, one major complication (pneumothorax) developed in one session (8%). No residual or recurrent tumors were identified at the ablation areas. However, new three solid tumors less than 1 cm in diameter developed during the follow-up period but ablation was withheld until these tumors had grown to more than 1 cm in size. The mean level of serum creatinine increased with 6.4% and the mean estimated glomerular filtration rate decreased by 12.8% after the last ablation compared to those before the initial ablation (P < 0.05).

CONCLUSION

Despite technical difficulties, percutaneous RFA is a promising treatment for VHL patients who cannot undergo surgery because of excellent treatment outcome and minimal change of renal function.

Radiofrequency ablation: a minimally invasive approach in kidney tumor management

The management and diagnosis of renal tumors have changed significantly over the last decade. Due to advances in imaging techniques, more than 50% of kidney tumors are discovered incidentally and many of them represent an early stage lesion. This has stimulated the development of nephron-sparing surgery and of the minimally invasive treatment options including ablative techniques, i.e., radiofrequency ablation (RFA) and cryoablation. The objective of the minimally invasive approach is to preserve the renal function and to lower the perioperative morbidity. RFA involves inducing the coagulative necrosis of tumor tissue. Being probably one of the least invasive procedures in kidney tumor management, RFA may be performed percutaneously under ultrasound (US), computed tomography (CT) or magnetic resonance (MR) guidance. Most of the studies show that the RFA procedure is efficient, safe and has a low complication rate. Due to the still limited data on the oncological outcome of RFA, the indication for this intervention remains limited to selected patients with small organ-confined renal tumors and contraindication to surgery or who have a solitary kidney. The aim of our study is to review the literature on RFA of kidney tumors.

Chyluria associated with radiofrequency ablation of renal cell carcinoma

Chyluria is a rare condition resulting from an abnormal connection between the lymphatic and urinary collecting system and is known to occur after partial nephrectomy. We report 2 cases of chyluria in patients after radiofrequency ablation of renal cell carcinoma diagnosed on surveillance computed tomography.