Treatment of renal tumors by percutaneous ultrasound-guided radiofrequency ablation using a multitined electrode: effectiveness and complications

Percutaneous ablation of renal tumors: Long-term outcomes

OBJECTIVE

To evaluate the long-term outcomes of renal tumor ablation, analyzing efficacy, long-term survival, and factors associated with complications and therapeutic success.

MATERIAL AND METHODS

We retrospectively reviewed 305 ablations (generally done with expandable electrodes) of 273 renal tumors between May 2005 and April 2019. We analyzed survival, primary and secondary efficacy, and complications according to various patient factors and tumor characteristics.

RESULTS

Mean blood creatinine was 1.14 mg/dL before treatment and 1.30 mg/dL after treatment (p < 0.0001). Complications were observed in 13.25% of the ablations, including major complications in in 4.97%. Complications were associated with age (p = 0.013) and tumor diameter (p < 0.0001). Primary efficacy was 96.28%. Incomplete ablation was more common in lesions measuring > 4 cm in diameter (p = 0.002). Secondary efficacy was 95.28%. The only factor associated with the risk of recurrence was the size of the tumor (p = 0.02). Overall survival was 95.26% at 1 year, 77.01% at 5 years, and 51.78% at 10 years, with no differences between patients with malignant and benign lesions. Mortality was higher in patients with creatinine >1 (p = 0.05) or ASA > 2 (p = 0.0001).

CONCLUSIONS

Percutaneous ablation is extremely efficacious for renal tumors; it improves the prognosis of renal carcinoma to the point where it does not differ from that of benign lesions. Complications are rare. Like survival, complications are associated with age and overall health status.

Contrast-enhanced ultrasonography to guide diagnostic and therapeutic interventional procedures

Although not necessary for the vast majority of ultrasound-guided procedures, intravenous contrast agents can be useful for procedures aimed at lesions that require contrast enhancement to be seen on ultrasonography. Using contrast-enhanced ultrasonography to guide procedures has two drawbacks: first, because enhancement from ultrasound contrast agents is short lived, it is often necessary to plan several injections; second, because the needle is poorly seen on contrast-enhanced ultrasonography, a dual image display format is necessary. Contrast-enhanced ultrasonography can be used for planning and monitoring diagnostic and therapeutic procedures, for guiding the procedures, and for follow-up. Using contrast-enhanced ultrasonography enables better results in both types of procedures; moreover, it can be used within cavities.

Contrast-enhanced ultrasonography to guide diagnostic and therapeutic interventional procedures

Although not necessary for the vast majority of ultrasound-guided procedures, intravenous contrast agents can be useful for procedures aimed at lesions that require contrast enhancement to be seen on ultrasonography. Using contrast-enhanced ultrasonography to guide procedures has two drawbacks: first, because enhancement from ultrasound contrast agents is short lived, it is often necessary to plan several injections; second, because the needle is poorly seen on contrast-enhanced ultrasonography, a dual image display format is necessary. Contrast-enhanced ultrasonography can be used for planning and monitoring diagnostic and therapeutic procedures, for guiding the procedures, and for follow-up. Using contrast-enhanced ultrasonography enables better results in both types of procedures; moreover, it can be used within cavities.

[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.

Urological technology: where will we be in 20 years' time?

Since prehistoric times, our understanding of urology has rapidly expanded. Whilst primitive urologists began by using urine as a therapeutic substance, modern urologists may find themselves removing a kidney remotely by driving a robotic arm, with seven degrees of movement, while using image overlay-augmented reality. This review provides an insight into the potential status of urological technology in 20 years' time, assessed through an analysis of developments in imaging, diagnostics, robotics and further technologies. A particular emphasis is given to the promising fields of minimally invasive techniques, nanotechnology and tissue engineering, which likely hold the key to a new era for urology.

Ultrasound-guided percutaneous radiofrequency ablation for treating small renal masses

INTRODUCTION

The objective of this study was to analyse and assess the experience with radiofrequency ablation of small renal masses using a contrast-enhanced, ultrasound-guided percutaneous approach for patients who are not suitable for surgical resection and/or who refused surveillance or observation.

MATERIAL AND METHOD

From January 2007 to August 2015, 164 treatments were performed on a total of 148 patients. We present the patients' clinical-radiological characteristics, oncological and functional results in the short and medium term.

RESULTS

The overall technical success rate was 97.5%, with a successful outcome in 1 session in 100% of the lesions≤3cm and 92% in lesions measuring 3-5cm. The mean tumour diameter in the patients for whom the treatment was ultimately successful was 2.7cm, while the mean diameter of these in the unsuccessful operations was 3.9cm (P<.05). There were no statistically significant differences in the serum creatinine levels and estimated glomerular filtration rates.

CONCLUSIONS

Despite the low rate of positive renal biopsies in the series, ultrasound-guided percutaneous radiofrequency ablation for treating small renal lesions appears to be an effective and safe procedure with a minimum impact on renal function, an acceptable oncologic control in the short and medium term and a low rate of complications.

The management of small renal masses: what is likely to change?

The diffusion of imaging has determined an increased discovery of small renal masses (SRMs). Recent publications have been reviewed to present the state of the art in the management of SRMs and to try to foresee the next steps in this challenging condition. The role of percutaneous biopsies is expanding, since management algorithms include also active surveillance and ablative therapies. However up to 30% of biopsies fail to provide histological diagnosis and there is the risk of under-evaluating high-grade tumors. Active surveillance has been proposed in patients with reduced life expectancy and numerous comorbidities. The average growth of SRMs is slow, and metastatic progression has been observed in about 1%. Ablative therapies (cryotherapy and radiofrequency ablation) are used in patients with relevant comorbidities or advanced age and unfit for surgery, but who desire active treatment. Compared to conservative surgical treatment both techniques have increased local progression rates, while metastatic progression is relatively low.Partial nephrectomy (PN) is the recommended curative treatment for SRMs and can be performed open, laparoscopically or robotically. Open PN represents the benchmark, with similar cancer specific survival and better preservation of renal function compared to nephrectomy. Laparoscopy is comparable to open surgery in terms of oncologic results, but a long learning curve is necessary. Perioperative outcomes of robot-assisted PN appear superior to laparoscopy and the learning curve is shorter, but data for oncological results are still immature. With the increasing diffusion of robotic technology it is likely more SRMs will be managed with this approach.

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-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.

Current management considerations for the incidentally detected small renal mass

BACKGROUND

Nephron-sparing treatments remain underutilized for the management of small renal masses despite a rise in incidentally detected renal cell carcinoma and a downward stage migration.

METHODS

Historical publications representative of currently accepted paradigms were reviewed, and the results of a contemporary scientific literature search conducted in PubMed focusing on studies involving humans, published in English, and inclusive of clinical trials, meta-analyses, randomized controlled trials, and practice guidelines are included. Results from contemporary retrospective trials augment the data when level I or II evidence is absent.

RESULTS

Phase III clinical trial results substantiate the long-held tenet that partial nephrectomy is equivalent to radical nephrectomy with respect to safety and oncologic efficacy. Further, minimally invasive techniques using laparoscopy and robotic assistance to achieve partial nephrectomy appear equally effective to traditional open techniques. Although no prospective randomized studies are available, large retrospective studies support the notion that active surveillance and thermal ablative techniques are viable options for carefully selected patients.

CONCLUSIONS

The management of small renal masses encompasses a host of therapeutic options, all of which must be considered and discussed with the individual patient.

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.

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.

Comparison of safety, renal function outcomes and efficacy of laparoscopic and percutaneous radio frequency ablation of renal masses

PURPOSE

With the increased incidence of low stage renal cancers, thermal ablation technology has emerged as a viable treatment option. Current AUA (American Urological Association) guidelines include thermal ablation as a treatment modality for select individuals. We compared the laparoscopic and percutaneous approach for the radio frequency ablation of renal tumors under the guidance of urological surgeons.

MATERIALS AND METHODS

We reviewed our radio frequency ablation database of patients with renal masses undergoing laparoscopic or computerized tomography guided percutaneous radio frequency ablation with simultaneous peripheral fiberoptic thermometry from November 2001 to January 2011 at a single tertiary care center. Data were collected on patient demographics, and surgical and clinicopathological outcomes stratified by approach.

RESULTS

A total of 298 patients with 316 renal tumors underwent laparoscopic (122 tumors) or computerized tomography guided (194 tumors) radio frequency ablation. There were no statistically significant differences between the laparoscopic and computerized tomography guided radio frequency ablation groups with respect to patient demographics, complication rates and renal functional outcomes (p>0.05). The 3-year Kaplan-Meier estimation of radiographic recurrence-free probability was 95% for computerized tomography guided radio frequency ablation and 94% for laparoscopic radio frequency ablation (p=0.84). Subanalysis of the 212 (67%) renal cell carcinoma tumors showed a 3-year Kaplan-Meier estimation of oncologic recurrence-free probability (post-ablation biopsy proven viable tumor) of 94% for computerized tomography guided radio frequency ablation and 100% for laparoscopic radio frequency ablation (p=0.16). Median followup was 21 months for laparoscopic radio frequency ablation) and 19 months for computerized tomography guided radio frequency ablation.

CONCLUSIONS

Laparoscopic and computerized tomography guided radio frequency ablation appear safe and effective with statistically equivalent rates of complications and recurrence.

Pretreatment imaging can be used to select imaging guidance, ultrasound alone versus CT plus ultrasound, for percutaneous renal radiofrequency ablation

OBJECTIVE

Although CT is most commonly used for guidance of radiofrequency ablation (RFA) of renal masses, other publications have shown that ultrasound alone may be used. Therefore, we compared the complications and technical effectiveness of renal RFA guided by ultrasound alone versus combined CT and ultrasound guidance.

MATERIALS AND METHODS

We retrospectively analyzed outcomes and complications of percutaneous renal RFA in two groups of patients for whom RFA was guided by either ultrasound alone (group 1) or combined CT and ultrasound (group 2). The sole factor in determining the method of guidance was preablation imaging. All other technical factors were consistent between the two groups.

RESULTS

There were 28 masses in 27 patients in group 1 and 32 masses in 29 patients in group 2. There was an overall major complication rate of 3.3% (2/60). Major complications occurred equally in group 2 (3.1% [1/32]) compared with group 1 (3.6% [1/28]). Overall ablative effectiveness was 93% (26/28) in group 1 and 84% (27/32) in group 2. There was no statistical difference between the two groups.

CONCLUSION

In proper hands, sonography guidance alone is a safe and effective method for performance of renal RFA in preselected cases and can decrease CT utilization. The use of CT is reserved for situations in which pretreatment RFA imaging suggests difficulty in ultrasound mass visualization or when the mass is in close proximity to structures that may be injured by thermal ablation.

Radiofrequency ablation of small renal masses as an alternative to nephron-sparing surgery: preliminary results

Introduction

Radical endoscopic minimal-invasive treatment methods, such as thermal ablation, are sought as an alternative to standard radical surgical treatment of kidney neoplasms. We analysed patients who could be qualified for radical treatment due to T1a renal tumour.

Material and methods

Twenty-three patients out of 129 who underwent radiofrequency thermal ablation of kidney tumours in the years 2003-2010 were analysed. The inclusion criteria were age below 70 years, lack of major comorbidities (ASA score 1, 2), and competent contralateral kidney. In all cases tumour size was below 4 cm. All patients were followed up with computed tomography (CT) and ultrasonography (USG) every 6 months for 3 years.

Results

In 20 patients kidney tumour was biopsied before radiofrequency ablation (RFA) and 10 of these biopsies were positive and revealed cancer. Six patients required additional treatment due to recurrence visible in CT – 3 with a positive biopsy result, 1 with negative and 2 without biopsy. Three of them were treated with a second session of RFA, 1 with radical nephrectomy and 2 with partial nephrectomy. No disease dissemination was observed and all patients who received additional treatment remain disease free.

Conclusions

The RFA can be safely used in selected patients with T1a tumour as an alternative to partial nephrectomy. Careful follow-up is required after thermal ablation and allows early detection and successful treatment of recurrences.

Local thermal ablation of renal cell carcinoma

PURPOSE

With evolving local thermal ablation technology, the clinical application of thermal ablation has been actively investigated in the treatment for renal cell carcinoma. We review the evolution and current status of radiofrequency ablation and microwave ablation for renal cell carcinoma.

MATERIALS AND METHODS

All articles published in English on radiofrequency ablation or microwave ablation as a treatment for renal cell carcinoma were identified with a MEDLINE® and PubMed® search from 1990 to 2010.

RESULTS

Local thermal ablation has several advantages, including keeping more normal renal units, relatively simple operation, easy tolerance, fewer complications, a shorter hospitalization and convalescence period. Long-term data has determined radiofrequency ablation is responsible for poor surgical candidates with renal cell carcinoma, however, tumor size, location and shape might affect the efficacy of radiofrequency ablation. Microwave ablation can induce large ablation volumes and yield good local tumor control. Associated complications appear to be low.

CONCLUSIONS

Local ablative approaches seem to represent an attractive alternative to extirpative surgery for the treatment of small renal neoplasms in select patients. Potential developments include concepts to improve the accuracy and effectiveness of thermal ablation by improving the guiding, monitoring capabilities and detection capacity of multi-center lesions to provide at least equivalent cancer control to conventional surgery.

Cryoablation vs. radiofrequency ablation for small renal masses

RATIONALE AND OBJECTIVES

Cancer of the kidney is the third most common cancer of the urinary tract, and renal cell carcinoma is the most lethal of all genitourinary tumors. The incidental discovery of renal cell carcinoma has increased with increased use of cross-sectional imaging. Concomitantly, minimally invasive ablative technologies, including image-guided cryoablation, radiofrequency ablation, and others, have evolved as therapeutic options for small renal masses.

MATERIALS AND METHODS

Between 2006 and 2009, 111 patients (age range, 31-91 years; mean age, 70 years) underwent percutaneous computed tomography-guided thermal ablation for suspected renal cell carcinoma at two major academic centers. Outcomes data were retrospectively collected and analyzed to compare recurrence rates for patients undergoing radiofrequency ablation (n = 41) versus cryoablation (n = 70).

RESULTS

There were four cases of suspicious enhancement on follow-up computed tomography or magnetic resonance imaging in each group, with cumulative imaging recurrence rates of 11% and 7% for radiofrequency ablation and cryoablation, respectively. Log rank test analysis revealed no significant difference between rates of imaging recurrence between the two groups (P = .6044).

CONCLUSIONS

These results suggest that the use of cryoablative technology will result in similar outcomes compared with radiofrequency ablation.

Long-term results after computed-tomography-guided percutaneous radiofrequency ablation for small renal tumors

PURPOSE

To present the long-term results and to identify possible risk factors for recurrence after radiofrequency ablation (RFA) for renal tumors.

PATIENTS AND METHODS

Thirty-one patients with a total of 39 renal tumors ranging from 1.3 to 7.5 cm (mean size 3.1 cm) were treated with RFA using a Rita Medical System model 1500 RF generator attached to a 15-gauge Starburst XL probe under percutaneous CT scan guidance. The average patient age was 61.4 years (range 37-86 y). Indications for RFA were bilateral tumors, presence of serious comorbidities, a high risk of development of additional renal-cell carcinomas, marginal renal function, and patient preference. No tumor was biopsied before treatment; therefore, only local control success rates could be provided. Recurrence was defined as enhancement or lesion enlargement on follow-up CT scan. Statistical analysis was performed to identify possible risk factors for recurrence. Parameters tested were age, sex, and number of ablation sessions, tumor size, location, multiplicity, body mass index, and American Society of Anesthesiologists score.

RESULTS

Initial ablation success rate was 90% and with repeated treatment, a success rate of complete ablation reached 97%. Average follow-up was 61.2 months (range 36-84 mos). Recurrence was seen in four tumors. The risk factor associated with recurrence was tumor size exceeding 4 cm (P < 0.01, relative risk [RR] = 3.31). Overall 3- and 5-year tumor control rate was 92% and 89%, respectively. Tumor size was also predictive for recurrence in the subgroup of 17 patients followed for more than 5 years (P = 0.02, RR = 3.15). Tumor control rate for this subgroup was 90%.

CONCLUSIONS

According to our results, larger tumor size was prognostic for recurrence after RFA for renal tumors. This treatment seems to demonstrate excellent tumor control long-term results, comparable to those achieved by nephron-sparing surgery in a selected group of patients.