Review of the efficacy and safety of radiofrequency ablation for the treatment of small renal masses

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.

Radiofrequency ablation versus partial nephrectomy for treatment of renal masses: A systematic review and meta-analysis

Our study was to collect the data available in the literature on radiofrequency ablation (RFA) and partial nephrectomy (PN) and conduct a cumulative analysis on perioperative outcomes, renal function outcomes, and survival to evaluate the overall safety and efficacy of RFA versus PN for small renal cell cancer (SRCC). A literature search was carried out using various electronic databases. Data including age, tumor size, comorbid disease, operation duration, hospital stay, pre- and postoperative estimated glomerular filtration rate (eGFR), major and minor complications, and local tumor recurrence and metastasis were collected for meta-analysis. Sixteen studies were included for this meta-analysis. The age of patients treated with RFA was significantly older than that of patients treated with PN [weighted mean difference (WMD) = 5.07 years]. There were more patients with cardiovascular disease in RFA group as compared with PN group [odds ratio (OR) = 4.24] before treatment. RFA was associated with a shorter length of hospital stay compared with PN (WMD = -2.02 days). No significant difference was found in major and minor complications between the two groups (major: OR = 0.74; minor: OR = 0.45). Preoperative eGFR and eGFR decline in RFA patients was significantly lower than that in PN patients (WMD = -7.27 and -4.82, respectively), whereas there was no significant difference in postoperative eGFR (WMD = -1.18). The local tumor recurrence rate in RFA group was higher than that in PN group (OR = 1.81). However, the distant metastasis rate was no statistical difference between the two groups (OR = 1.63). RFA is a suitable therapeutic option for older patients and those at high risk for SRCC because of a low risk of operation and better preservation of renal function.

Renal cell carcinoma

The treatment of renal cell carcinoma (RCC) has changed greatly over the past 15 years. Progress in the surgical management of the primary tumor and increased understanding of the molecular biology and genomics of the disease have led to the development of new therapeutic agents. The management of the primary tumor has changed owing to the realization that clean margins around the primary lesion are sufficient to prevent local recurrence, as well as the development of more sophisticated tools and techniques that increase the safety of partial nephrectomy. The management of advanced disease has altered even more dramatically as a result of new agents that target the tumor vasculature or that attenuate the activation of intracellular oncogenic pathways. This review summarizes data from prospective randomized phase III studies on the surgical management and systemic treatment of RCC, and provides an up to date summary of the histology, genomics, staging, and prognosis of RCC. It describes the management of the primary tumor and offers an overview of systemic agents that form the mainstay of treatment for advanced disease. The review concludes with an introduction to the exciting new class of immunomodulatory agents that are currently in clinical trials and may form the basis of a new therapeutic approach for patients with advanced RCC.

Renal ablation update

Thermal ablative technologies have evolved considerably in the recent past and are now an important component of current clinical guidelines for the treatment of small renal masses. Both radiofrequency ablation and cryoablation have intermediate-term oncologic control that rivals surgical options, with favorable complication profiles. Studies comparing cryoablation and radiofrequency ablation show no significant difference in oncologic control or complication profile between the two modalities. Early data from small series with microwave ablation have shown similar promising results. Newer technologies including irreversible electroporation and high-intensity-focused ultrasound have theoretical advantages, but will require further research before becoming a routine part of the ablation armamentarium. The purpose of this review article is to discuss the current ablative technologies available, briefly review their mechanisms of action, discuss technical aspects of each, and provide current data supporting their use.

[Irreversible electroporation: the new generation of local ablation techniques for renal cell carcinoma]

BACKGROUND

Local ablation techniques are a major focus of current developments in oncology. The primary aim is to retain organs and preserve organ functions without compromising the oncological outcome.

METHOD

Irreversible electroporation (IRE) is a novel ablation technique that involves the application of high-voltage pulses to induce cell apoptosis without causing thermal damage to the target tissue or adjacent structures.

AIM

First published in 2005 IRE is currently undergoing preclinical and clinical trials in several areas of oncology and the initial results have been promising. The IRE technique could be a significant development in ablation treatment for renal cell carcinoma (RCC) but decisive proof of its effectiveness for local RCC has not yet been provided. This study presents the results of preclinical and initial clinical trials which are discussed and compared with those of other ablation techniques in order to demonstrate the current value of IRE.

Complications of radiofrequency ablation of hepatic, pulmonary, and renal neoplasms

Percutaneous thermal ablation has emerged as a viable technique for treatment of numerous solid organ malignancies. As the number of these procedures increases, so do the complications that are seen. Most common complications are generally related to bleeding from the target organ during or after the procedure and from thermal injury to adjacent structures. The nature of these injuries depends on the particular organ being treated, therefore it it best to categorize them this way. We will review the more common complications seen following the ablation of tumors in the liver, kidney, and lung, discuss the clinical presentation associated with each, and suggest precautions to help avoid them in the future. Understanding the potential risks associated with this procedure is critical for treatment planning and fundamental for performing these procedures safely.

Microwave ablation treatment of liver cancer with 2,450-MHz cooled-shaft antenna: an experimental and clinical study

PURPOSE

To evaluate effects of microwave ablation with a 2,450-MHz internally cooled-shaft antenna in animal experiments and in a clinical study.

METHODS

Microwave ablation was performed using a cooled-shaft antenna in eight in vivo (36 ablations) porcine livers. The coagulation diameters achieved in different microwave ablation parameter groups were compared. Sixty patients (44 men, 16 women; mean age 53 years) with 96, 1-8 cm (mean 3.20 +/- 0.17 cm) liver cancers were treated with the same microwave ablation technique. Complete ablation (CA), local tumor progression (LTP) rates and complications were determined.

RESULTS

In vivo livers, short axis diameter correlated with the coagulation duration in a sigmoidal curve fashion (60-W group R(2) = 0.76, 80-W group R(2) = 0.87), with a relative plateau achieved within 10 min for power settings of 60 or 80 W. Within 10 min in the 60 and 80-W groups, respectively, 89 and 85.76% of maximum short axis diameter were achieved. CA rates in small (3.0 cm), intermediate (3.1-5.0 cm) and large (5.1-8.0 cm) liver cancers were 96.43% (54/56), 92.31% (24/26) and 78.57% (11/14), respectively. During a mean follow-up period of 17.17 +/- 6.52 months, LTP occurred in five (5.21%) treated cancers. There was no significant difference in the CA and LTP rate between the HCC and liver metastasis patient subgroups (P > 0.05).

CONCLUSIONS

The short axis diameter enlargement has a relative plateau within 10 min by fixing power output to 60 or 80 W, using the 2,450-MHz internally cooled-shaft antenna in vivo porcine livers. Effective local tumor control was achieved during one microwave ablation session.