Energieablative Therapie von Nierentumoren

Solid renal tumours with a diameter <4 cm may be effectively cured by partial nephrectomy but this is associated with a complication rate of 15–20%. In addition, these tumours are more frequently diagnosed in the elderly (<70 years) and 26% are aggressive G3 and potentially hazardous tumours. Since these tumours are frequently unifocal, spherical, peripherally located and easily accessible for minimally invasive approaches, energy ablative techniques are attractive less invasive therapeutic options. These tumours may be treated by freezing (cryoablation) or by heat (radiofrequency ablation, high intensified focused ultrasound). Cryoablation seems to be the most reliable technique with a 1.6% recurrence rate over 3 years follow-up but only 1.8% complications. Conversely skipping renders RFA unreliable in highly vascularised tumours >3 cm with 23% vital tumours to be found at histological work-up. Laparoscopic HIFU is still experimental. Percutaneous techniques are less effective as compared with laparoscopy with recurrence rates ranging between 13–21% (cryoablation) and 14–18% (RFA). In addition, oncological follow-up relies solely on radiological measurements, frequently without histological verification thus making percutaneous techniques unpredictable.     

Ablative therapies in the treatment of small renal tumors: How far from standard of care?

ObjectivesTo determine the current clinical value of minimally invasive thermoablative techniques (MI thermoablative T) to ablate small renal tumors through a literature review.MethodsA literature search was conducted on the most commonly used MI thermoablative T for small renal tumors, namely cryoablation (CA) and radiofrequency ablation (RFA). Primary objective was to carry out a comparative assessment of the complication rate, recurrence rate, and cancer specific survival rates across techniques. Secondary objective was to critically review technical aspects of the procedures.ResultsFive-year follow-up data were available only for laparoscopic CA, with a recurrence rate varying from 0% to 15%. Follow-up of percutaneous cryoablation (PCA) and RFA did not go beyond 2 years, and excellent recurrence free rates were obtained at the price of a significant retreatment rate. The need for retreatment was perceived as lower with PCA than with RFA. Overall complication rate did not exceed 5% in all techniques albeit laparoscopic CA carried a significant degree of invasiveness compared with other percutaneous techniques.ConclusionsMI thermoablative T for small renal tumors should still be confined to carefully selected patients. PCA seems to hold the premises for the best compromise between low invasiveness and high efficacy, while RFA appears highly advantageous in terms of procedural costs.     

Ureteropelvic junction obliteration resulting in nephrectomy after radiofrequency ablation of small renal cell carcinoma

Percutaneous radiofrequency ablation is a minimally invasive treatment that is currently used to treat renal tumors. Despite its minimally invasive nature, potential serious complications can occur. We report the second case of ureteropelvic junction obstruction after radiofrequency ablation that resulted in nephrectomy. The use of radiofrequency ablation should be considered with caution, particularly when tumors are centrally located or abut the renal pelvis. Additional data are needed to better define the indications and contraindications to minimally invasive ablative technologies when used in the clinical setting.     

Current status of minimally invasive ablative techniques in the treatment of small renal tumours

OBJECTIVES: In the current era, minimally invasive surgery using ablative techniques for the treatment of small renal tumours has become a more common and feasible treatment option. In this review, we present recent data regarding the utility of needle ablative techniques in the experimental and clinical settings. METHODS: We performed a comprehensive evaluation of available published data from 1997 to 2006 that were identified with PubMed. Official proceedings of internationally known scientific societies held in the same time period were also assessed. RESULTS: Two main thermoablative techniques, cryoablation (CA) and radiofrequency ablation (RFA), represent the current available minimally invasive treatments for renal cell carcinoma (RCC). CA has been more extensively studied and has gained acceptance from patients and physicians. The procedure is well tolerated by patients even with serious concomitant diseases. RFA is delivered with a monopolar alternating current. Morbidity rates for this modality remain slightly higher than those for cryotherapy. Both techniques are associated with highly successful cancer control rates at short-to-medium follow-up in patients with tumour size <3 cm. Multiple lesions can be treated simultaneously and the procedures can be repeated. However, long-term follow-up data are still lacking. CONCLUSION: Minimally invasive 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 of thermal ablation using novel imaging modalities with reduction in side-effects and optimised selection and follow-up of patients to provide at least equivalent cancer control to conventional surgery.     

Energy ablative therapy of renal tumours

Solid renal tumours with a diameter <4 cm may be effectively cured by partial nephrectomy but this is associated with a complication rate of 15-20%. In addition, these tumours are more frequently diagnosed in the elderly (<70 years) and 26% are aggressive G3 and potentially hazardous tumours. Since these tumours are frequently unifocal, spherical, peripherally located and easily accessible for minimally invasive approaches, energy ablative techniques are attractive less invasive therapeutic options. These tumours may be treated by freezing (cryoablation) or by heat (radiofrequency ablation, high intensified focused ultrasound). Cryoablation seems to be the most reliable technique with a 1.6% recurrence rate over 3 years follow-up but only 1.8% complications. Conversely skipping renders RFA unreliable in highly vascularised tumours >3 cm with 23% vital tumours to be found at histological work-up. Laparoscopic HIFU is still experimental. Percutaneous techniques are less effective as compared with laparoscopy with recurrence rates ranging between 13-21% (cryoablation) and 14-18% (RFA). In addition, oncological follow-up relies solely on radiological measurements, frequently without histological verification thus making percutaneous techniques unpredictable.     

Duodenopleural fistula formation after percutaneous radiofrequency ablation for recurrent hepatocellular carcinoma

Radiofrequency ablation (RFA) is a treatment option in the management of unresectable or recurrent hepatocellular carcinoma (HCC). It can be performed either through laparotomy or in a minimally invasive manner by percutaneous, laparoscopic or thoracoscopic routes. Percutaneous RFA is associated with reduced surgical trauma and thus can be performed in patients with significant comorbidities. The procedure can be repeated after short intervals for sequential ablation of multiple liver lesions. However, the associated risks should not be underestimated. This is the first report of a rare complication of duodeno-pleural fistula after percutaneous RFA of a recurrent subcapsular HCC. The risk of bowel perforation during the ablation of subcapsular HCC requires special attention, since only the position of the tip of the electrode, but not the zone of ablation, can be assessed accurately by imaging during the procedure. Our case demonstrated that there was leakage of bowel content from the duodenal injury site into the pleural cavity through the RFA track. Subsequent uncontrolled infection resulted in empyema thoracis and led to the death of the patient.     

Percutaneous ultrasound-guided radiofrequency ablation of recurrent renal cell carcinoma in renal allograft after partial nephrectomy

Percutaneous thermal ablation is increasingly being studied in the treatment of renal tumors. Because radiofrequency ablation is a minimally invasive and nephron-sparing procedure, it is ideally suited for patients with a single kidney, multiple tumors, or contraindications to conventional surgery. We report on a patient with recurrent renal cell carcinoma in a transplanted kidney that was successfully treated with percutaneous ultrasound-guided radiofrequency ablation.     

Treatment of renal tumors with radiofrequency ablation

BACKGROUND: Radiofrequency (RF) energy has been investigated as a minimally invasive modality for ablating small renal tumors. Recent advances in the application of this technology have improved its safety and effectiveness. MATERIALS AND METHODS: We describe the technology of RF application and review the current delivery systems as applied to renal tumor ablation. We also review relevant animal studies, which have revealed the natural history of ablated renal tissue. Finally, we examine recent human trials with an emphasis on longer-term follow-up, imaging, complications, and successful ablation according to tumor location within the kidney; i.e., central v peripheral. RESULTS: Radiofrequency ablation can be performed safely in a minimally invasive fashion either percutaneously or laparoscopically. Energy delivery varies, and available systems include dry, wet, cooled-tip, and bipolar electrodes. Heat rise and subsequent charring in the tissue adjacent to the electrode is limited by temperature or impedance-based feedback systems. In animal studies, ablation results in complete cell kill, as judged by nicotinamide adenine dinucleotide diaphorase staining. Clinical trials with intermediate follow-up show excellent success rates. Tumors >3 cm and central tumors have a higher recurrence rate after RFA than smaller, more peripheral tumors. CONCLUSIONS: The current literature suggests that RFA is a promising minimally invasive method of treating small renal tumors. Nevertheless, long-term follow-up is still required, and questions remain regarding the optimal delivery system, duration of ablation, and method of surveillance.     

Radiofrequency Ablation of Invasive Breast Carcinomas: A Phase II Trial

Background Local ablative therapy of breast cancer represents the next frontier in the minimally invasive breast-conservation treatment. We conducted a phase II trial to evaluate radiofrequency ablation (RFA) of invasive breast carcinomas. Methods Consecutive patients from two Mexican Institutions with invasive breast cancers < 4 cm, with no multicentric tumors and no previous chemotherapy were included in this trial. Under ultrasound guidance, the tumor and a 5 mm margin of surrounding breast tissue were ablated with saline-cooled RFA electrode followed by surgical resection. Routine pathologic analysis and viability evaluation with NADPH-diaphorase stain were performed to assess tumor ablation. Procedure-associated morbidity was recorded. Results Twenty-five patients were included. Mean patient age was 55.3 years (range 42–89 years). Mean tumor size was 2.08 cm (range 0.9–3.8 cm). Fourteen tumors (56%) were <2 cm. The mean ablation time was 11 minutes using a mean power of 35 W. During ablation, the tumors become progressively echogenic that corresponded with the region of severe RFA injury at pathologic examination. Of the 25 patients treated, NADPH stain showed no evidence of viable malignant cells in 19 patients (76%), with significant difference between tumors <2 cm (complete necrosis in 13 of 14 cases, 92.8%) vs. those >2 cm (complete necrosis 6 of 11 cases, 54.5%) (P < .05). No significant morbidity was recorded. Conclusions RFA is a promising minimally invasive treatment of small breast carcinomas, as it can achieve effective cell killing with a low complication rate. Further studies are necessary to optimize the technique and evaluate its future role as local therapy for breast cancer.     

Radiofrequency ablation for the treatment of small renal masses: safety and oncologic efficacy

The successful introduction of radio frequency ablation (RFA) into various surgical fields has fueled the interest of the urological community to study its application in small renal masses (SRM). However, some controversies remain regarding its oncologic efficacy. In this paper, we review the complication rates and highlight local ablative success and long-term oncologic outcomes of recent, larger RFA series. Review of the recent literature (Medline from January 2003 through May 2011 with the terms ("radiofrequency ablation" OR "catheter ablation") AND ("renal cell carcinoma" OR "renal tumor" OR "renal mass" OR "renal cancer" OR "kidney cancer"). Twelve RFA studies including a minimum of 35 treated tumors, and representing 717 patients were identified and analyzed for local ablative success rates and complications. Reported complications were classified according to Dindo-Clavien. Another five studies representing 172 patients were identified to assess long-term oncologic outcomes. Final pathology revealed 82.3% biopsy-proven renal cell carcinomas (RCCs) in 8 of the 12 evaluable RFA studies. Local ablative success rates after a first RFA session ranged from 67% to 100%. However, accepting a 8.8% repeat ablation rate, final success rates were 89.7-100%, with 7 of 12 studies showing final ablative success in >95%. These results demonstrate RFA to achieve adequate local tumor control regardless of histology. Risk of complications was 13.2%. Of complications, 10% were minor (grade I or II), while only 3.2% were major complications (grade ≥III). Five papers were identified describing oncological outcome at a minimum follow-up of 53 months (range 53-61.2). Progression-free survival, cancer-specific survival and overall survival ranged from 79.9 to 93.8%, 98 to 100% and 58.3 to 85%, respectively. This literature review confirms that RFA can deliver durable local tumor control and excellent long-term oncological outcomes. However, in order to achieve this, a repeat ablation rate of 8.8% has to be accepted. Complication rates are low, with 10% grade I-II and only 3.2% grade >III. These observations render RFA an attractive alternative to surgery in an elderly or comorbid population.     

Radio-frequency ablation of renal cell carcinoma: early clinical experienc.

Purpose: To report the authors' early experience with radio-frequency (RF) ablation of renal cell carcinoma.Materials and Methods: Twenty-four percutaneous RF ablation treatments for nine tumors were performed in eight patients with renal cell carcinoma. Indications included coexistent morbidity, previous surgery, or solitary kidney in patients with a life expectancy shorter than 10 years. Smaller (⩽3-cm) peripheral lesions (n = 3) were treated with single electrodes. All but one of the larger (>3 cm) and/or central lesions (n = 6) were treated with cluster or multiple electrodes. Patients returned for a second treatment when follow-up imaging depicted tumor enhancement. Follow-up imaging was performed at 1 and 3 months and then at 6-month intervals, with a mean follow-up of 10.3 months. Seven patients were alive at least 6 months after their initial treatment.Results: All five exophytic tumors were free of enhancement. One of three central tumors was free of enhancement. One tumor had both central and exophytic components and was free of enhancement. Three tumors were 3 cm or smaller and free of enhancement. Of the six tumors larger than 3 cm, four were free of enhancement.Conclusion: Percutaneous RF ablation is a promising treatment for select patients with renal cell carcinoma. The ultimate role of this modality will continue to evolve and warrants further study.CommentaryNew minimally invasive technologies are currently being applied to the field of nephron-sparing surgery (NSS) for renal cell carcinoma (RCC) in an effort to decrease operative time, pain, morbidity and hospital stay. Methods of tumor ablation have included cryotherapy, radio-frequency ablation (RFA), high intensity focused ultrasound (HIFU), laser and microwave coagulation. These new modalities are currently being administered laparoscopically or percutaneously; ultimately, completely extracorporeal techniques may be feasible.The primary mechanism of tissue destruction with RFA is thermonecrosis. Radio-frequency energy causes high frequency current flow from the needle electrode into the surrounding tissue. This causes ionic agitation, molecular friction, cellular warming with rapid dessication and cell death. The size and configuration of the lesion are related to the amount of energy delivered, ablation time, tissue impedance, electrolyte content of the tissue and surface area of the electrode. It is a major technical challenge to control for each of these variables independently.The major concern with RFA and related ablative technologies is the ability to image the destructive process precisely as it is being administered, thereby minimizing injury to normal adjacent parenchyma while assuring complete tumor ablation. Since a surgical specimen is not removed for pathologic study, histologic documentation of complete tumor destruction and accurate tumor staging/grading are not available. Meticulous long-term clinical and radiographic follow-up of treated patients is ultimately needed to validate the efficacy of ablative techniques such as RFA for treating renal malignancy.Andrew C. Novick, M.D.     

Case report: radiofrequency ablation-induced renal-pelvic obstruction resulting in nephrectomy

Radiofrequency ablation (RFA) has emerged as a minimally invasive nephron-sparing treatment for small (<4-cm) renal tumors. Post-RFA complications have been reported. We describe a patient who developed complete renal-pelvic obstruction after RFA. To our knowledge, this is the first such case to be reported and the second reported renal-unit loss as the result of collecting-system obstruction after RFA.     

Percutaneous Radiofrequency Ablation versus Partial Hepatectomy for Multicentric Small Hepatocellular Carcinomas: A Nonrandomized Comparative Study

Background  

The aim of this study was to compare the results of percutaneous radiofrequency ablation (RFA) with those of partial hepatectomy (PH) in the treatment of multicentric small hepatocellular carcinomas (HCCs). With advances in RFA, it is not known whether the minimally invasive approach with percutaneous RFA could attain comparable survival outcomes but with a lower morbidity in patients with multicentric HCCs.     

Trends in the operative management of renal tumors over a 14-year period

OBJECTIVE: To review the trends in the operative management of renal tumours over a 14-year period at a university hospital, as the therapeutic options available for treating renal tumours have increased over the past decade. PATIENTS AND METHODS: The study was a retrospective chart review of 1621 consecutive patients undergoing treatment for renal tumours from January 1991 to March 2005. The characteristics assessed included patient demographics, tumour size, operative duration and treatment. RESULTS: During the study period, 624 (38.6%) open, 883 (54.6%) laparoscopic and 111 (6.7%) percutaneous approaches were performed. The number of renal tumours treated increased annually, as did the use of minimally invasive techniques (93.4% in 2005). Conversely, the number of open surgical treatments used declined both absolutely and proportionally. Over the study period, for tumours of 7 cm, open radical nephrectomy (ORN) was the most common method of treatment over all years. However, since 2002, laparoscopic radical nephrectomy (LRN) surgery has been increasingly used over ORN for treating this tumour group (73% LRN vs 19.2% ORN in 2004). CONCLUSION: The available treatment options for renal tumours have increased significantly since the early 1990s. At a university hospital in which there are physicians with a specific interest in minimally invasive surgery and ablative treatments, minimally invasive approaches have become the standard treatment.     

Bildgestützte minimal-invasive Chirurgie und andere lokaltherapeutische Verfahren bei primären Lebertumoren

Background

The incidence of primary liver tumors is rising. Modern minimally invasive, image-guided procedures offer a potentially curative therapy option.

Objective

The aim of this study was to evaluate the multitude of image-guided minimally invasive procedures concerning their evidence-based effect on local tumor control and overall survival.

Material and methods

A systematic search of MEDLINE focused on hepatocellular cancer, minimally invasive treatment, local ablative therapy, therapeutic stratification and comparative studies was performed.

Results

The level of evidence varied greatly depending on the procedure used. The highest quality evidence including prospective randomized studies was found for radiofrequency ablation (RFA) of hepatocellular cancer. The RFA is superior with respect to local tumor control and overall survival in comparison to other ablative procedures. Prospective randomized studies comparing surgery and RFA showed diverging and contradictory results. Microwave ablation and robotic stereotactic irradiation showed sufficient potential in retrospective studies in comparison to RFA and surgery in order to confirm the techniques in randomized studies. There is only anecdotal evidence concerning high intensity focused ultrasound (HIFU) and irreversible electroporation. Percutaneous ethanol injection (PEI), cryoablation and laser-induced thermal therapy (LITT) were inferior techniques to RFA in most studies.

Conclusion

Minimally invasive resection and local ablative therapies based on structured imaging and image reporting can improve the prognosis of patients with hepatocellular cancer even in patients that exceed the BCLC 0/A stage.

     

Kidney cancer ablative therapy: Indications and patient selection

The increased application of radiographic imaging has paralleled a simultaneous increase in the detection of incidental and asymptomatic renal neoplasms. The reference standard for treating small renal tumors includes open and laparoscopic partial nephrectomy. The primary objectives of ablative renal procedures are to duplicate the excellent oncologic outcomes of partial nephrectomy while decreasing patient morbidity and shortening hospitalization and overall convalescence. Ablation, with cryotherapy or radiofrequency probes, offers the advantages of minimally invasive surgery, but with a significantly lower complication rate than laparoscopic partial nephrectomy. Ablation now represents a major change in surgical thinking as tumors are ablated and left in situ. This article reviews the status of the two ablative modalities currently available for clinical application, cryoablation and radiofrequency ablation.     

Percutaneous radiofrequency ablation-induced perinephric hematoma with acute renal failure in a solitary kidney

Iatrogenic occurrences (including radiologically guided renal biopsy, shockwave lithotripsy, and minimally invasive ablative procedures) of subcapsular hematoma that lead to acute renal failure are rare but serious. The advancement of minimally invasive procedures has led to an increase in this complication, especially in patients with a solitary kidney. Fortunately, prompt surgical evacuation of the hematoma in these patients allows decompression of the renal parenchyma and recovery of renal function. We report a case of acute renal failure in a patient with a solitary kidney that resulted from a subcapsular hematoma as a complication of radiofrequency ablation.     

Radiofrequency ablation of small renal cortical tumours in healthy adults: renal function preservation and intermediate oncological outcome

OBJECTIVES

To present the glomerular filtration rate (GFR) and oncological outcomes in a series of patients with cT1a renal cortical tumours treated with radiofrequency ablation (RFA), a non‐ischaemic minimally invasive ablative method, as nephron‐sparing surgery gives excellent oncological outcomes and preserves renal function.

PATIENTS AND METHODS

Healthy (American Society of Anesthesiologists, ASA, I and II) patients with cT1a renal masses were identified, and clinical and radiographic data were reviewed to assess indications, complications, radiological evidence of disease recurrence, and renal function. Changes in GFR were calculated. Radiological recurrence was defined as any new enhancement (>10 Hounsfield units) after absence of enhancement on initial 6‐week computed tomography.

RESULTS

Four patients were ASA I and 59 were ASA II; the median (range) age was 58 (20–84.6) years and the lesion diameter 2.1 (1–4.0) cm. Preoperative needle biopsy was diagnostic in 89% of patients, including 75% diagnostic of renal cell carcinoma (RCC). At a median (range) follow‐up of 34 (1.0–80) months the renal preservation rate was 97%. One patient had a nephrectomy for biopsy‐confirmed recurrence of RCC at 55 months; a second had a nephrectomy at 24 months for suspected radiographic recurrence, but had no evidence of disease on final pathology. A fifth (20%) of the patients had chronic kidney disease at the time of diagnosis. The median GFR before and after RFA was 76.3 and 74.3 mL/min/m² (difference 2.0 mL/min/m²).

CONCLUSION

RFA might be a reasonable treatment choice for the healthy patient, with appropriate informed consent. Intermediate results suggest excellent oncological outcomes and preservation of renal function.     

Pulmonary radiofrequency ablation in a single lung patient

Recurrence in the contralateral lung of patients who have undergone pneumonectomy for lung cancer is often not surgically treatable. Percutaneous radiofrequency ablation (RFA) of tumours is an emerging minimally invasive technique which has recently been used in the treatment of lung cancer. The case history is presented of a patient who had previously undergone pneumonectomy in whom recurrence of lung cancer was treated by RFA. The procedure was performed under CT guidance and was uneventful. At follow up 9 months later the tumour appeared to have ablated. To our knowledge, no similar case has previously been reported in the literature.     

Percutaneous ultrasound-guided radiofrequency ablation of an allograft renal cell carcinoma: a case report

BackgroundRenal cell carcinomas (RCCs) are rarely described in transplanted kidneys. Available therapeutic strategies range from allograft nephrectomy to nephron-sparing procedures such as partial nephrectomy or image-guided thermal ablation. Percutaneous radiofrequency ablation (RFA) is a minimally invasive technique which provides promising oncologic outcomes in small allograft RCCs while preserving allograft function. So far, only a few cases have been reported in the transplant setting. We describe a renal transplant RCC successfully approached by ultrasound-guided RFA.MethodsA 42-year-old renal transplant recipient developed a small subcapsular allograft RCC at 11 years after transplantation. The decline in glomerular filtration rare prompted us to preserve as much parenchyma as possible. Ultrasound-guided RFA was performed under light sedation and local analgesia in a single session with a Starbust Talon needle.ResultsPostablation contrast-enhanced ultrasound displayed a 25×23 mm avascular area of complete necrosis. After 3 months gadolinium-enhanced magnetic resonance imaging confirmed the absence of viable tumor tissue and while the patient did not experience any graft function reduction (serum creatinine 2.6 mg/dL).ConclusionsImage-guided RFA represents a promising therapeutic modality for small allograft RCCs in recipients with mild graft dysfunction and/or elevated surgical risk. It is associated with low morbidity and parenchymal preservation.