Long-term oncologic outcomes after radiofrequency ablation for T1 renal cell carcinoma. Eur Urol. 2013;63:486-492. [PMID: 22959191 DOI: 10.1016/j.eururo.2012.08.062]

High-powered microwave ablation of t1a renal cell carcinoma: safety and initial clinical evaluation

PURPOSE

Percutaneous radiofrequency ablation and cryoablation are accepted alternative treatments for small renal cell carcinomas (RCC) in high-risk patients. The recent development of high-powered microwave (MW) ablation offers theoretical advantages over existing ablation systems, including higher tissue temperatures, more reproducible ablation zones, and shorter procedural times. The purpose of this study is to review the feasibility, safety, and early efficacy of a novel high-powered percutaneous MW ablation system to treat RCC.

METHODS

An institutional database identified 53 consecutive patients with biopsy-proven RCC ≤4 cm (55 tumors) who were treated with percutaneous MW ablation using a novel MW ablation system. All patients had percutaneous renal mass biopsy, which identified RCC before ablation. Postprocedure follow-up imaging was performed by contrast-enhanced computed tomography or magnetic resonance imaging.

RESULTS

Mean patient age was 66 years and 81% of patients were male. RCC subtypes included clear cell (n=25), papillary (n=12), and unspecified (n=18) and Fuhrman grades 1, 2, 3, and ungraded in 15, 25, 1, and 14 patients, respectively. The mean tumor diameter was 2.6 cm (range 0.8-4.0 cm). Six low-grade complications were recorded during 53 (11.3%) procedures: five Clavien Grade 1 (urine retention, fluid overload, and atrial fibrillation) and one Grade 2 (hemorrhage requiring transfusion). The postprocedure estimated glomerular filtration rate was not significantly changed from preprocedure levels (median: -1.1%, p=0.10). Median follow-up was 8 months (interquartile range [IQR] 5-18.25) with 0/38 (0%) patients demonstrating evidence of local recurrence or metastasis during surveillance imaging.

CONCLUSIONS

Use of a high-powered MW ablation system for the treatment of T1a RCC is feasible, safe, and efficacious with short-term follow-up. A longer follow-up is warranted to evaluate oncologic outcomes.

Long-term oncologic outcomes following radiofrequency ablation with real-time temperature monitoring for T1a renal cell cancer

OBJECTIVE

Few studies report long-term follow-up of renal cancer treated by radiofrequency ablation (RFA), thus limiting the comparison of this modality to well-established long-term follow-up series of surgically resected renal masses. Herein, we report long-term oncologic outcomes of renal cancer treated with RFA in a single institution.

METHODS AND MATERIALS

We retrospectively reviewed patients treated between November 2001 and October 2012 with laparoscopic-guided or computed tomography-guided RFA. All treatments were performed with real-time thermometry ensuring target ablation temperature (>60°C) was adequately reached. Only patients with biopsy-confirmed T1a-category cancer and a follow-up period>48 months were included in our analysis. Follow-up included office visits, laboratory work, and periodic contrast-enhanced imaging. Survival was calculated using the Kaplan-Meier analysis. Overall complications were reported using the Clavien-Dindo scale.

RESULTS

Of 434 RFA cases, 53 treatments in 50 patients met the inclusion criteria. Of these, 29 were treated with computed tomography-guided RFA and 24 with laparoscopic-guided RFA. The mean follow-up interval was 65.6 months (48.5-120.2), and the mean renal mass size was 2.3 cm (0.3-4.0). There were 4 (7.5%) local recurrences and 1 case of distant metastases with no local recurrence. The 5-year overall survival was 98%, cancer-specific survival was 100%, and recurrence-free survival was 92.5%. The complication rate was 26.4%, which included 71% of Clavien-Dindo grade I and 29% of grade II. Mean estimated glomerular filtration rate preoperatively and at the most recent follow-up visit was 77 and 66 ml/min, respectively.

CONCLUSIONS

When performed on selected patients, while monitoring real-time temperatures to ensure adequate treatment end points, RFA offers favorable long-term oncologic outcomes approaching those reported for partial nephrectomy.

Percutaneous ablation of the small renal mass-techniques and outcomes

An increasing number of T1a renal cell carcinomas are being diagnosed in recent years, in part due to incidental detection from the increased use of cross-sectional imaging. Although partial nephrectomy is still considered the primary treatment for these small renal masses, percutaneous ablation is now being performed as a standard therapeutic, nephron-sparing approach in patients who are poor surgical candidates. Clinical studies to date have demonstrated that percutaneous ablation is an effective therapy with acceptable outcomes and low risk in the appropriate clinical settings. This article will review various clinical aspects regarding the percutaneous ablation of small renal masses, including patient selection, preprocedural preparations, and the procedural considerations of commonly employed ablative technologies. Specific techniques such as radiofrequency ablation, cryoablation, microwave ablation, irreversible electroporation, and high-intensity focused ultrasound will be addressed in detail. In addition, the technical and oncologic outcomes of percutaneous ablation will be discussed and referenced to that of partial nephrectomy.

Cancer-free survival and local tumor control after impendence-based radiofrequency ablation of biopsy-proven renal cell carcinomas with a minimum of 1-year follow-up

OBJECTIVES

There are numerous reports describing the use of radiofrequency ablation (RFA) to treat renal cell carcinoma. Many series, however, describe heterogeneous populations, lack histologic descriptions, use various RFA systems, and indicate tumor destruction by different ablation end points. This study examined the outcomes of computed tomography-guided, impedance-based RFA of biopsy-proven renal cell carcinoma clinically staged as T1a with a minimum of 1 year of postablation follow-up.

METHODS AND MATERIALS

This retrospective study identified all consecutive patients who had undergone renal RFA since May 2005 at our institution. Patients without biopsy-proven renal cell carcinoma (RCCa) were excluded. Of the patients who met these criteria, evaluation was limited to patients with a minimum of 12 months of follow-up. Data collected from the patients' electronic medical and radiologic records included demographic data, tumor-related data, procedural details, and clinical follow-up visits.

RESULTS

A total of 39 patients (46 lesions) met the inclusion criteria. The mean tumor diameter was 2.6 cm (range: 1.2-4.0 cm). The most common histologies were clear cell (n = 27) and papillary (n = 16) renal cancer. The lesion location was equally divided between upper pole (n = 16), middle pole (n = 16), and lower pole (n = 14). Overall, 83% of the tumors were exophytic. No residual or recurrent enhancing mass was identified in the ablation bed on post-RFA imaging during the mean follow-up period of 35.3 months (range: 12-83). All patients were treated in a single encounter and no lesion required a second ablation; technical success (absence of residual tumor) on the initial post-RFA imaging study was 46 of 46 (100%). Clinical success was achieved in 45 of 46 lesions (98%); residual, viable tumor was found in a pretransplant nephrectomy specimen on postprocedure day 127. The mean cancer-free survival was 36.2 months. Comparison of preablation and postablation renal function found no statistically significant change.

CONCLUSIONS

The consistent outcomes in our post-RFA imaging and clinical surveillance allow us to offer image-guided ablation to patients with T1a RCCa as a valid treatment option offering long-term cancer-free survival. Impedance-based RFA in a carefully selected patient population with T1a RCCa is a reliable treatment option, with disease-free survival rates that are comparable to partial nephrectomy.

Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes. Online supplemental material is available for this article .

The contemporary role of ablative treatment approaches in the management of renal cell carcinoma (RCC): focus on radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), and cryoablation

INTRODUCTION

Currently, most of renal tumors are small, low grade, with a slow growth rate, a low metastatic potential, and with up to 30 % of these tumors being benign on the final pathology. Moreover, they are often diagnosed in elderly patients with preexisting medical comorbidities in whom the underlying medical conditions may pose a greater risk of death than the small renal mass. Concerns regarding overdiagnosis and overtreatment of patients with indolent small renal tumors have led to an increasing interest in minimally invasive, ablative as an alternative to extirpative interventions for selected patients.

OBJECTIVE

To provide an overview about the state of the art in radiofrequency ablation (RFA), high-intensity focused ultrasound, and cryoablation in the clinical management of renal cell carcinoma.

METHODS

A PubMed wide the literature search of was conducted.

RESULTS

International consensus panels recommend ablative techniques in patients who are unfit for surgery, who are not considered candidates for or elect against elective surveillance, and who have small renal masses. The most often used techniques are cryoablation and RFA. These ablative techniques offer potentially curative outcomes while conferring several advantages over extirpative surgery, including improved patient procedural tolerance, faster recovery, preservation of renal function, and reduction in the risk of intraoperative and postsurgical complications. While it is likely that outcomes associated with ablative modalities will improve with further advances in technology, their application will expand to more elective indications as longer-term efficacy data become available.

CONCLUSION

Ablative techniques pose a valid treatment option in selected patients.

[Focal therapy in urology: kidney cancer]

Focal therapy has gained attention in the treatment of small renal masses (SRM). However, its use is limited due to scarce data on long-term outcomes. The availability of such data is significantly lower as compared to the relevant data on surgery outcomes. At the same time, minimally invasive surgery has seen the development of laparoscopic nephron-sparing surgery and, recently, robot-assisted surgery. Our purpose is to review the possibilities of treatment for SMR with particular attention on focal therapy. Clinical series and comprehensive reviews support safety and mid/long-term efficacy of renal cryoablation or radiofrequency ablation. Comparative studies and meta-analysis outlined oncological inferiority against partial nephrectomy in local tumor control. For smaller and more peripheral lesions, radiofrequency ablation showed best indications than cryoablation. There are significant demographic and tumor differences between patients treated by one or another approach. The correct indication for each treatment seems to be of key importance to achieve the best oncological and functional outcome. Open partial nephrectomy remains the gold standard treatment for PMR, but laparoscopic approaches have been showing similar results.

Active surveillance for small renal masses diagnosed in elderly or comorbid patients: looking for the best treatment strategy

INTRODUCTION

Aim of this study is to provide our results after long-term active surveillance (AS) protocol for small renal masses (SRMs), and to report the outcomes of patients who remained in AS compared to those who underwent delayed surgical intervention.

PATIENTS AND METHODS

We retrospectively reviewed our database of 58 patients diagnosed with 60 contrast enhancing SRMs suspicious for renal cell carcinoma (RCC). All patients had clinical and radiological follow-up every 6 months. We evaluated the differences between patients who remained on AS and those who underwent surgical delayed intervention.

RESULTS

The mean age was 75 years, the mean follow-up was 88.5 months. The median initial tumor size at presentation was 2.6cm, and the median estimated tumor volume was 8.7cm(3). The median linear growth rate of the cohort was 0.7cm/year, and the median volumetric growth rate was 8.8 cm(3)/year. Death for metastatic disease occurred in 2 patients (3.4%). No correlation was found between initial tumor size and size growth rate. The mean linear and volumetric growth rates of the group of patients who underwent surgery was higher than in those who remained on surveillance (1.9 vs. 0.4cm/year and 16.1 vs. 4.6 cm(3)/year, respectively; P<.001).

CONCLUSIONS

Most of SRMs demonstrate to have an indolent course and low metastatic potential. Malignant disease could have faster linear and volumetric growth rates, thus suggesting the need for a delayed surgical intervention. In properly selected patients with low life-expectancy, AS could be a reasonable option in the management of SRMs.

Chronic kidney disease in patients with renal cell carcinoma

Renal cell carcinoma (RCC) is diagnosed in over 65,000 Americans annually, and earlier detection and advances in surgical techniques have resulted in improved oncological outcomes. Given that diabetes and hypertension are independent risk factors for the development of RCC, it is not surprising that diabetic nephropathy or hypertensive nephrosclerosis are commonly encountered in these patients. Data support that at least one third of the 300,000 kidney cancer survivors in the United States have or will develop CKD; however, the effect of CKD in this clinical setting has largely evaded the attention of the medical community. It is likely that CKD which develops from postsurgical therapy for RCC may limit long-term outcomes by increasing the risk for cardiovascular morbidity and mortality. To further improve the clinical outcomes for kidney cancer patients, better recognition and management of CKD, which requires coordination among urologists, pathologists, and nephrologists, will be essential.

US-guided percutaneous microwave ablation versus open radical nephrectomy for small renal cell carcinoma: intermediate-term results

PURPOSE

To review intermediate-term clinical outcomes of microwave ablation (MWA) compared with open radial nephrectomy (ORN) in small renal cell carcinoma (RCC) patients and to identify prognostic factors associated with two techniques.

MATERIALS AND METHODS

This retrospective study was institutional review board-approved. A total of 163 patients (127 men and 36 women) with small RCC (≤4 cm) were included from April 2006 to March 2012. Sixty-five patients underwent MWA and 98 patients underwent ORN. Survival, recurrence, and renal function changes were compared between the two groups. Effect of changes in key parameters (ie, overall survival, RCC-related survival, and metastasis-free survival) was statistically analyzed with the log-rank test.

RESULTS

Although overall survival after MWA was lower than that after ORN (P = .002), RCC-related survival was comparable to ORN (P = .78). Estimated 5-year overall survival rates were 67.3% after MWA and 97.8% after ORN; for RCC-related survival, estimated 5-year rates were 97.1% after MWA and 97.8% after ORN. There was one local tumor recurrence 32 months after MWA and none after ORN. Major complication rates were comparable (P = .81) between the two techniques (MWA, 2.5% vs ORN, 3.1%). The MWA group had less surgical time (P < .001), estimated blood loss (P < .001), and postoperative hospitalization (P < .001). Multivariate analysis showed age (P = .014), tumor type (P = .003), postoperative urea nitrogen (P = .042), comorbid disease (P = .005), and treatment modality (P < .001) may become survival rate predictors.

CONCLUSION

In intermediate term, ultrasonographically guided percutaneous MWA and ORN provide comparable results in oncologic outcomes. MWA appears to be a safe and effective technique for management of small RCC in patients with little loss of renal function.

[Treatment by radiofrequency ablation for a renin-secreting juxtaglomerular tumour: a case report]

Juxtaglomerular cell tumors are rare and benign tumors, occurring in young patients. The standard treatment is partial nephrectomy. We report the case of a young 22-year-old patient with a renin-secreting tumor diagnosed during an exploration of severe hypertension associated with hypokalemia that we treated by radiofrequency ablation.

Long-term outcomes in healthy adults after radiofrequency ablation of T1a renal tumours

OBJECTIVE

To report the long-term oncological and renal function outcomes in healthy adults treated with radiofrequency ablation (RFA) for small renal masses.

MATERIALS AND METHODS

We retrospectively analysed the medical records of otherwise healthy patients (those with American Society of Anesthesiologists symptom score 1 or 2) with clinical T1a renal tumours who underwent RFA at our institution between March 2001 and July 2012. Radiographic follow-up with contrast imaging was performed at 6 weeks, 6 months, 1 year and annually thereafter. Local recurrence was defined as any new enhancing lesion (>10 HU) after the initial negative post-treatment computed tomography results. The estimated glomerular filtration rates (eGFRs) before and after RFA were calculated using the Cockgroft-Gault equation.

RESULTS

We performed RFA on 58 renal tumours in 52 patients. The mean tumour size was 2.2 cm with a median (interquartile range) follow-up of 60 (48-90) months. Three (5.1%) of the treated masses had tumour recurrence after initial RFA. The 5- and 10-year recurrence-free survival rate was 94.2%. There were no recurrences after 3 years. Three (5.1%) patients died during the follow-up, which gave 5- and 10-year overall survival rates of 95.7% and 91.1%. No patient developed metastatic renal cell carcinoma (RCC) and none died from RCC. Paired analysis showed that the eGFR values at a median follow-up of 40 months did not differ significantly from those before RFA.

CONCLUSION

With long-term follow-up, RFA provides durable oncological and functional outcomes for selected T1a renal tumours in otherwise healthy patients.

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

Objectives

Patients and Methods

Results

Conclusions

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.