Treatment efficacy of radiofrequency ablation of 338 patients with hepatic malignant tumor and the relevant complications

Complications of Percutaneous Radiofrequency Ablation for Hepatocellular Carcinoma

Radiofrequency ablation (RFA) is a potentially curative treatment option for early Hepatocellular carcinoma. The RFA is considered safe with a relatively low incidence of complications ranging from 2%-7.9%. Though most of the complications are self-limiting, sometimes they can be life-threatening. The occurrence of the particular complication depends on various factors like tumour location and morphology, underlying disease and ablation technique. A detailed understanding of potential complications along with the associated risk factors will help to employ strategies to prevent them, identify them early and manage them when they occur. This article demonstrates various radiofrequency ablation-related complications and discusses the risk factors and technical strategies to minimise them and achieve complete ablation of the tumour.

Computer simulation-based nanothermal field and tissue damage analysis for cardiac tumor ablation

Radiofrequency ablation is a nominally invasive technique to eradicate cancerous or non-cancerous cells by heating. However, it is still hampered to acquire a successful cell destruction process due to inappropriate RF intensities that will not entirely obliterate tumorous tissues, causing in treatment failure. In this study, we are acquainted with a nanoassisted RF ablation procedure of cardiac tumor to provide better outcomes for long-term survival rate without any recurrences. A three-dimensional thermo-electric energy model is employed to investigate nanothermal field and ablation efficiency into the left atrium tumor. The cell death model is adopted to quantify the degree of tissue injury while injecting the Fe3O4 nanoparticles concentrations up to 20% into the target tissue. The results reveal that when nanothermal field extents as a function of tissue depth (10 mm) from the electrode tip, the increasing thermal rates were approximately 0.54362%, 3.17039%, and 7.27397% for the particle concentration levels of 7%, 10%, and 15% compared with no-particle case. In the 7% Fe3O4 nanoparticles, 100% fractional damage index is achieved after ablation time of 18 s whereas tissue annihilation approach proceeds longer to complete for no-particle case. The outcomes indicate that injecting nanoparticles may lessen ablation time in surgeries and prevent damage to adjacent healthy tissue.

A case of hemoperitoneum after percutaneous radiofrequency ablation in a patient with hepatocellular carcinoma

We report a case of hemoperitoneum after percutaneous radiofrequency ablation in a patient with hepatocellular carcinoma. A 60-year-old female was hospitalized for the treatment of thrombasthenia and cirrhosis caused by chronic Hepatitis C, and computed tomography revealed hepatocellular carcinoma, which was treated by percutaneous radiofrequency ablation. After the ablation, hemoperitoneum was suspected because of the low hemoglobin level with abdominal pain. Approximately 6 h after the ablation treatment, the patient suddenly fell into a shock state and died. In this case, medical treatment-related death including malpractice was suspected, and forensic autopsy was performed. The abdominal cavity contained 910 mL of dark red fluid blood and 210 g of soft hemocoagula. Moreover, several puncture marks were observed on the liver surface and diaphragm, and there was no clear damage to the main arteries and veins. Considering the macroscopic and microscopic findings, the cause of death was assumed as hemorrhagic shock due to the hemoperitoneum caused by the damage to the liver by radiofrequency ablation. It is important to consider all the indications and adverse effects of radiofrequency ablation.

In Vivo Evaluation of a Novel Radiofrequency Ablation Electrode in Pig Livers

(1) Background: Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is an alternative treatment for pancreatic tumors. Currently, EUS-RFA has been trialled to treat hepatic tumors. However, little has been reported about optimal settings for EUS-RFA in patients with hepatic tumors. We evaluated the ablation effect after in vivo RFA using a new EUS-RFA electrode in a pig model. (2) Methods Four pigs were used for the in vivo test. The in vivo testing was divided into two tests based on the length of the RFA electrode (0.5, 0.7, 1 or 1.5 cm), the ablation power (30 W or 50 W), and the ablation time (10 or 15 s). In test one, ablation effect was evaluated based on the electrode length and power. In test two, ablation effect was assessed based on power and time. (3) Results: In test one, the ablation width and depth correlated with the length of the electrode and power (0.5 cm, 10 W, 10 s: width 0.46 cm, depth 0.65 cm vs. 1.5 cm, 75 W, 10 s: width 0.77 cm, depth 1.80 cm). In test two, ablation width and depth were similar when RFA was set at 1.5cm, 50 W, and 10 s or 1 cm, 30 W, and 15 s (0.65 cm, 1.14 cm vs. 0.65cm, 1.26 cm). (4) Conclusions: The relationship between electrode length, ablation power, and ablation time, and the resulting ablation effect in pig livers suggest that EUS-RFA produces effective ablation while minimizing thermal injury.

Exploration of Novel Pathways Underlying Irreversible Electroporation Induced Anti-Tumor Immunity in Pancreatic Cancer

Advancements in medical sciences and technologies have significantly improved the survival of many cancers; however, pancreatic cancer remains a deadly diagnosis. This malignancy is often diagnosed late in the disease when metastases have already occurred. Additionally, the location of the pancreas near vital organs limits surgical candidacy, the tumor's immunosuppressive environment limits immunotherapy success, and it is highly resistant to radiation and chemotherapy. Hence, clinicians and patients alike need a treatment paradigm that reduces primary tumor burden, activates systemic anti-tumor immunity, and reverses the local immunosuppressive microenvironment to eventually clear distant metastases. Irreversible electroporation (IRE), a novel non-thermal tumor ablation technique, applies high-voltage ultra-short pulses to permeabilize targeted cell membranes and induce cell death. Progression with IRE technology and an array of research studies have shown that beyond tumor debulking, IRE can induce anti-tumor immune responses possibly through tumor neo-antigen release. However, the success of IRE treatment (i.e. full ablation and tumor recurrence) is variable. We believe that IRE treatment induces IFNγ expression, which then modulates immune checkpoint molecules and thus leads to tumor recurrence. This indicates a co-therapeutic use of IRE and immune checkpoint inhibitors as a promising treatment for pancreatic cancer patients. Here, we review the well-defined and speculated pathways involved in the immunostimulatory effects of IRE treatment for pancreatic cancer, as well as the regulatory pathways that may negate these anti-tumor responses. By defining these underlying mechanisms, future studies may identify improvements to systemic immune system engagement following local tumor ablation with IRE and beyond.

Starting a Fire Without Flame: The Induction of Cell Death and Inflammation in Electroporation-Based Tumor Ablation Strategies

New therapeutic strategies and paradigms are direly needed for the treatment of cancer. While the surgical removal of tumors is favored in most cancer treatment plans, resection options are often limited based on tumor localization. Over the last two decades, multiple tumor ablation strategies have emerged as promising stand-alone or combination therapeutic options for patients. These strategies are often employed to treat tumors in areas where surgical resection is not possible or where chemotherapeutics have proven ineffective. The type of cell death induced by the ablation modality is a critical aspect of therapeutic success that can impact the efficacy of the treatment and systemic anti-tumor immune system responses. Electroporation-based ablation technologies include electrochemotherapy, irreversible electroporation, and other modalities that rely on pulsed electric fields to create pores in cell membranes. These pores can either be reversible or irreversible depending on the electric field parameters and can induce cell death either alone or in combination with a therapeutic agent. However, there have been many controversial findings among these technologies as to the cell death type initiated, from apoptosis to pyroptosis. As cell death mechanisms can impact treatment side effects and efficacy, we review the main types of cell death induced by electroporation-based treatments and summarize the impact of these mechanisms on treatment response. We also discuss potential reasons behind the variability of findings such as the similarities between cell death pathways, differences between cell-types, and the variation in electric field strength across the treatment area.

Defeating Cancers' Adaptive Defensive Strategies Using Thermal Therapies: Examining Cancer's Therapeutic Resistance, Ablative, and Computational Modeling Strategies as a means for Improving Therapeutic Outcome

BACKGROUND

Diverse thermal ablative therapies are currently in use for the treatment of cancer. Commonly applied with the intent to cure, these ablative therapies are providing promising success rates similar to and often exceeding "gold standard" approaches. Cancer-curing prospects may be enhanced by deeper understanding of thermal effects on cancer cells and the hosting tissue, including the molecular mechanisms of cancer cell mutations, which enable resistance to therapy. Furthermore, thermal ablative therapies may benefit from recent developments in computer hardware and computation tools for planning, monitoring, visualization, and education.

METHODS

Recent discoveries in cancer cell resistance to destruction by apoptosis, autophagy, and necrosis are now providing an understanding of the strategies used by cancer cells to avoid destruction by immunologic surveillance. Further, these discoveries are now providing insight into the success of the diverse types of ablative therapies utilized in the clinical arena today and into how they directly and indirectly overcome many of the cancers' defensive strategies. Additionally, the manner in which minimally invasive thermal therapy is enabled by imaging, which facilitates anatomical features reconstruction, insertion guidance of thermal probes, and strategic placement of thermal sensors, plays a critical role in the delivery of effective ablative treatment.

RESULTS

The thermal techniques discussed include radiofrequency, microwave, high-intensity focused ultrasound, laser, and cryosurgery. Also discussed is the development of thermal adjunctive therapies-the combination of drug and thermal treatments-which provide new and more effective combinatorial physical and molecular-based approaches for treating various cancers. Finally, advanced computational and planning tools are also discussed.

CONCLUSION

This review lays out the various molecular adaptive mechanisms-the hallmarks of cancer-responsible for therapeutic resistance, on one hand, and how various ablative therapies, including both heating- and freezing-based strategies, overcome many of cancer's defenses, on the other hand, thereby enhancing the potential for curative approaches for various cancers.

Ablation approach for primary liver tumors: Peri-operative outcomes

BACKGROUND AND OBJECTIVES

Ablation is a common treatment modality for malignant primary liver tumors(PLTs), outcomes following laparoscopic (LA) versus open ablation (OA) are ill-defined. This project compares peri-procedural outcomes of LA versus OA for PLTs.

MATERIALS AND METHODS

Patients with PLTs undergoing radiofrequency ablation were queried from ACS NSQIP Database (2005-2013) using CPT codes. Patients undergoing percutaneous ablation or hepatic resection were excluded. Multivariable logistic regression analyses determined the association of ablation approach with 30-day morbidity and mortality.

RESULTS

Of 5747 with PLTs, 655 (11.4%) ablations were identified: 177 (27.0%) underwent OA, 478 (73.0%) underwent LA. Patients undergoing LA had lower mortality (1.9% vs 5.1%, P = 0.026), lower minor morbidity (2.3% vs 5.7%, P = 0.031), and lower major morbidity (4.2% vs 17.0%, P < 0.001). Adjusting for demographics, disease-specific variables (preoperative ascites, total bilirubin, platelet count, albumin, and INR), 30-day mortality (OR 3.85, 95%CI: 1.38-10.80, P = 0.010), minor morbidity (OR 2.98, 95%CI: 1.16-7.67, P = 0.024), and major morbidity (OR 4.59 95%CI: 2.41-8.76, P < 0.001) were statistically lower in LA. OA demonstrated increased length of stay(LOS) (5 vs 2 days, P < 0.001), and longer operative time (152 vs 112 min, P < 0.001).

CONCLUSION

LA offers decreased peri-procedural morbidity, mortality, and reduced LOS. LA should be the preferred method for hepatic ablation.

Thermal ablation of pancreatic cyst with a prototype endoscopic ultrasound capable radiofrequency needle device: A pilot feasibility study

BACKGROUND AND OBJECTIVES

Pancreatic cysts are evaluated by endoscopic ultrasound and fine needle aspiration (EUS). The only accepted treatment is pancreatectomy, which is associated with morbidity and mortality. This study evaluated the optimal thermal dosimetry of a novel radiofrequency ablation device using a standard electrosurgical unit in ex vivo cyst models.

METHODS

A modified EUS 22-gauge monopolar needle prototype with a tip electrode connected to a standard electrosurgical unit (Erbe USA, Marietta, GA, USA) was used to induce a subboiling point temperature. A cyst model was created using 2-cm sections of porcine small intestine ligated and filled with saline. After ablation, the cyst models were prepared for pathological evaluation. The epithelial layers were measured in at least two different sites with a micrometer and compared with the corresponding control sample.

RESULTS

Thirty-two cyst models were ablated with maximum temperatures of 50°C, 60°C, 90°C, and 97°C in 8, 11, 11, and 2 cysts, respectively. Longer ablation times were required to induce higher temperatures. A trend in the reduction in thickness of the measured layers was observed after exposure to higher temperatures. A temperature over 50°C was required for the ablation of the muscularis, submucosa, and villi, and over 60°C was required to ablate the mucosal crypts.

CONCLUSIONS

In a preclinical model, a novel radiofrequency EUS-capable needle connected to a standard electrosurgical unit using standard low-voltage coagulation provided ablation in a temperature-dependent fashion with a threshold of at least 60°C and a safe cyst margin below 97°C. This potentially will allow low-cost, convenient cyst ablation.

Embolization for Bleeding after Hepatic Radiofrequency Ablation

PURPOSE

To evaluate safety and clinical efficacy of embolization for management of bleeding after hepatic radiofrequency (RF) ablation.

MATERIALS AND METHODS

From January 2000 to December 2014, 5,196 patients with 9,743 tumors underwent 8,303 RF ablation sessions. Of these patients, 62 experienced bleeding after hepatic RF ablation; 15 patients (12 men and 3 women; mean age 62 y; range, 49-76 y) underwent embolization and composed the final study cohort. Tumors were hepatocellular carcinomas in 13 (87%) patients and metastatic adenocarcinomas from colorectal cancer in 2 (13%) patients. Mean number of tumors was 1.5 (22 nodules; range, 1-3). Tumor locations were segment I (n = 1), segment II (n = 2), segment III (n = 1), segment IV (n = 1), segment V (n = 3), segment VI (n = 5), segment VII (n = 1), and segment VIII (n = 9). Mean tumor size was 2.3 cm (range, 0.9-5 cm).

RESULTS

Median time interval between presentation and angiography was 22 hours (mean 38.4 h; range, 3-168 h). On angiography, contrast extravasation with or without pseudoaneurysm was seen in all 15 patients; 14 patients underwent transarterial embolization, and 1 patient underwent percutaneous transhepatic portal vein embolization. Successful hemostasis was achieved in all patients. There was no rebleeding within 30 days after embolization. No embolization-related major complications were observed.

CONCLUSIONS

Embolization is safe and effective for controlling bleeding related to hepatic RF ablation without the need for surgery.

Periportal low attenuation associated with liver metastasis from colorectal cancer: evaluation using multi-detector-row CT with pathological correlation

OBJECTIVES

Periportal low attenuation (PPLA) associated with metastatic liver cancer is occasionally seen on multi-detector-row CT (MDCT). The purpose of this study was to investigate the MDCT patterns of the PPLA and to correlate it with pathological findings.

METHODS

We retrospectively reviewed the MDCT images of 63 patients with metastatic liver cancers from colorectal adenocarcinoma. On MDCT scans, PPLA associated with liver metastasis was visualized in six patients with colorectal cancer. In these six patients who had undergone surgical resection, the radiologic-pathologic correlation was analyzed. All patients underwent a single contrast-enhanced MDCT within 1 month before surgical resection. The six liver cancers were pathologically proven to be moderately differentiated adenocarcinoma. We assessed the PPLA on MDCT concerning the distribution patterns and contrast enhancement with pathological correlation.

RESULTS

In five of the patients, the PPLA extended to the hilar side from metastatic liver cancer. Pathologically, there was no cancer invasion into the intra-hepatic periportal area; however, massive lymphedema and fibrosis occurred in all six cases.

CONCLUSIONS

PPLA on the hilar and peripheral sides of hepatic metastasis from colorectal cancer may be present suggesting lymphedema and fibrosis of portal tracts not always indicating cancer infiltration.

Tumor Regression in HCC Patient with Portal Vein Tumor Thrombosis after Intraportal Radiofrequency Thermal Ablation

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Portal vein tumor thrombosis (PVTT) is a frequent entity in HCC, which strictly limits the gold standard treatment options such as surgical resection and transarterial chemoembolization. Therefore, the prognosis of patients with PVTT is extremely poor and an emergence of seeking an alternative option for intervention is inevitable. We present a case of a 60-year-old male patient with HCC induced PVTT who was subjected to the intraportal RFA and stenting-VesOpen procedure. No additional medical intervention was performed. The repeated CT performed 5 months after the VesOpen procedure revealed significant decrease of the tumor size, patent right, and main portal vein and a recanalization of the left portal vein, which was not processed. At this time point, liver functional tests, appetite, and general condition of the patient were improved evidently. This report designates the RFA as an instrumental option of therapeutic intervention for HCC patients with PVTT.

In-utero radiofrequency ablation in fetal piglets: Lessons learned

INTRODUCTION

Radiofrequency ablation (RFA) is increasingly utilized in minimally invasive fetal intervention. However, the response of different fetal tissues to RFA is poorly characterized. We sought to determine the extent of RFA damage in a fetal environment.

METHODS

90Day gestation Yorkshire piglets (term 115days) were subjected to RFA of the chest and abdominal viscera under various temperatures and wattages. The extent of tissue damage was determined by NADPH diaphorase histochemistry.

RESULTS

Tyne temperature was widely variable and displayed varying responses between lung and liver tissue. Tyne exposure to amniotic fluid resulted in an increase in amniotic fluid temperature. Collateral damage, even across the diaphragm, was readily seen, and ultrasonography did not always reflect this injury.

CONCLUSIONS

Utilization of extracorporeal tynes heats fluid at a greater rate than solid tissue and reliance on temperature sensitive probes may result in overheating. The extent of injury may extend beyond damage observed by ultrasound examination and varies for different tissues. Additional studies on the use of devices that regulate tyne temperature are needed to define optimal conditions and better define the extent of adjacent tissue injury.

Colorectal Cancer Liver Metastases: Biopsy of the Ablation Zone and Margins Can Be Used to Predict Oncologic Outcome

Purpose To establish the prognostic value of biopsy of the central and marginal ablation zones for time to local tumor progression (LTP) after radiofrequency (RF) ablation of colorectal cancer liver metastasis (CLM). Materials and Methods A total of 47 patients with 67 CLMs were enrolled in this prospective institutional review board-approved and HIPAA-compliant study between November 2009 and August 2012. Mean tumor size was 2.1 cm (range, 0.6-4.3 cm). Biopsy of the center and margin of the ablation zone was performed immediately after RF ablation (mean number of biopsy samples per ablation zone, 1.9) and was evaluated for the presence of viable tumor cells. Samples containing tumor cells at morphologic evaluation were further interrogated with immunohistochemistry and were classified as either positive, viable tumor (V) or negative, necrotic (N). Minimal ablation margin size was evaluated in the first postablation CT study performed 4-8 weeks after ablation. Variables were evaluated as predictors of time to LTP with the competing-risks model (uni- and multivariate analyses). Results Technical effectiveness was evident in 66 of 67 (98%) ablated lesions on the first contrast material-enhanced CT images at 4-8-week follow-up. The cumulative incidence of LTP at 12-month follow-up was 22% (95% confidence interval [CI]: 12, 32). Samples from 16 (24%) of 67 ablation zones were classified as viable tumor. At univariate analysis, tumor size, minimal margin size, and biopsy results were significant in predicting LTP. When these variables were subsequently entered in a multivariate model, margin size of less than 5 mm (P < .001; hazard ratio [HR], 6.7) and positive biopsy results (P = .008; HR, 3.4) were significant. LTP within 12 months after RF ablation was noted in 3% (95% CI: 0, 9) of necrotic CLMs with margins of at least 5 mm. Conclusion Biopsy proof of complete tumor ablation and minimal ablation margins of at least 5 mm are independent predictors of LTP and yield the best oncologic outcomes. (©) RSNA, 2016.

EUS-guided radiofrequency ablation for management of pancreatic insulinoma by using a novel needle electrode (with videos)

BACKGROUND AND AIMS

Insulinomas are one of the most common functional pancreatic neuroendocrine tumors. Surgical removal is the standard of care. Patients unfit for or refusing surgery need an alternative nonsurgical method to alleviate symptoms. EUS has been used to localize, aspirate, and tattoo insulinomas and to inject alcohol for local ablation. This study is aimed at assessing the feasibility of EUS-guided radiofrequency ablation (EUS-RFA) for managing patients with a symptomatic insulinoma by using a novel EUS-RFA needle electrode.

METHODS

The EUS-RFA system used consists of a prototype 19-gauge needle electrode, generator, and internal cooling system. EUS-guided RFA is performed under real-time visualization at 50 W to ablate pancreatic insulinomas.

RESULTS

In this observational human case series from a tertiary care center, 3 patients with a symptomatic pancreatic insulinoma, not eligible for surgery, underwent EUS-RFA by using an internally cooled prototype needle electrode. All had rapid symptom relief with biochemical improvement and remained symptom free at 11 to 12 months of follow-up. There were no procedure-related adverse events.

CONCLUSIONS

EUS-RFA with the novel device can be considered in select patients with a symptomatic pancreatic insulinoma based on preliminary findings of a beneficial effect without adverse events. Assessment of the safety profile requires larger prospective trials.

Endoscopic ultrasound-fine needle injection for oncological therapy

The minimal invasiveness and precision of endoscopic ultrasound (EUS) has lead to both its widespread use as a diagnostic and staging modality for gastrointestinal and pancreaticobiliary malignancies, and to its expanding role as a therapeutic modality. EUS-guided celiac plexus neurolysis is now a well-accepted modality for palliation of pain in patients with pancreatic cancer. EUS-guided ablation, brachytherapy, fiducial marker placement, and antitumor agent injection have been described as methods of performing minimally invasive oncological therapy. EUS-fine needle injection may be performed as adjunctive, alternative, or palliative treatment. This review summarizes the studies to date that have described these methods. A literature search using the PubMed/MEDLINE databases was performed. While most published studies to date are limited with disappointing outcomes, the concept of a role of EUS in oncological therapy seems promising.

Clinical modalities for management of gastric cancer hepatic metastasis

The best treatment for gastric cancer hepatic metastasis is still widely debated. Gastric cancer hepatic metastases has long been justified the indication of palliative chemotherapy. Inspired by the good results of the management of colorectal cancer hepatic metastases, surgeons have focused on the curative or palliative treatment of gastric cancer hepatic metastases. The current clinical modalities used for treatment of gastric cancer hepatic metastasis include liver resection, systemic chemotherapy, radiofrequency ablation (RFA), hepatic arterial infusion (HAI), and palliative gastrectomy. This article presents a review of the literature on hepatic resection, RFA, HAI, palliative gastrectomy, and systemic chemotherapy for the treatment of liver metastases in gastric carcinoma, and discusses the indications and long-term results.

High survival in patients operated for small isolated liver metastases from gastric cancer: a multi-institutional study

BACKGROUND

Although several studies have reported the outcomes of surgery for the treatment of liver metastases of gastric cancer (GLM), indications for liver resection for gastric metastases remain controversial. This study was designed to identify prognostic determinants that identify operable hepatic metastases from gastric cancer and to evaluate the actual targets of surgical therapy.

METHODS

Retrospective analysis was performed on outcomes for 24 consecutive patients at five institutions who underwent gastrectomy for gastric cancer followed by curative hepatectomy for GLM between 2000 and June 2012.

RESULTS

Overall 5-year survival and median survival were 40.1 % and 22.3 months, respectively. Uni- and multivariate analyses showed that liver metastatic tumour size less than 5 cm was the most important predictor of overall survival (OS, p = 0.03). Four patients survived >5 years. Repeat hepatectomy was performed in three patients. Two of these patients have remained disease-free since the repeat hepatectomy.

CONCLUSIONS

GLM patients with metastatic tumour diameter less than 5 cm maximum are the best candidates for hepatectomy. Hepatic resection should be considered as an option for gastric cancer patients with liver metastases.

Complications after percutaneous ablation of liver tumors: a systematic review

BACKGROUND

Although ablation therapy has been accepted as a promising and safe technique for treatment of unrespectable hepatic tumors, investigation of its complications has been limited. A physician who performs ablation treatment of hepatic malignancies should be aware of the broad spectrum of complications. Proper management is possible only if the physician Performing ablation understands the broad spectrum of complications encountered after ablation.

OBJECTIVES

TO SYSTEMATICALLY REVIEW THE COMPLICATIONS AFTER DIFFERENT ABLATION MODALITIES: Radiofrequency ablation (RFA), microwave ablation (MWA) and Nano knife for the treatment of liver tumors and analyze possible risk factors that precipitate these complications.

SEARCH METHODS

WE PERFORMED ELECTRONIC SEARCHES IN THE FOLLOWING DATABASES: MEDLINE, EMBASE and COCHARNE. Current trials were identified through the Internet (from January 1, 2000 to January 1, 2014). We included only studies who specific mentioned complications after liver ablation therapy (RFA/MWA/Nano knife).

MAIN RESULTS

A total of 2,588 publications were identified, after detailed examination only 32 publications were included in the review. The included studies involved 15,744 participants. According to the type of technique, 13,044 and 2,700 patients were included for RFA and MWA. Analysis showed a pooled mortality of 0.15% for RFA, and 0.23% for MWA.

CONCLUSIONS

This systematic review gathers information from controlled clinical trials and observational studies which are vulnerable to different types of bias, never the less RFA and MWA can be considered safe techniques for the treatment of liver tumors.

Optimal management of colorectal liver metastases in older patients: a decision analysis

BACKGROUND

Comparative trials evaluating management strategies for colorectal cancer liver metastases (CLM) are lacking, especially for older patients. This study developed a decision-analytic model to quantify outcomes associated with treatment strategies for CLM in older patients.

METHODS

A Markov-decision model was built to examine the effect on life expectancy (LE) and quality-adjusted life expectancy (QALE) for best supportive care (BSC), systemic chemotherapy (SC), radiofrequency ablation (RFA) and hepatic resection (HR). The baseline patient cohort assumptions included healthy 70-year-old CLM patients after a primary cancer resection. Event and transition probabilities and utilities were derived from a literature review. Deterministic and probabilistic sensitivity analyses were performed on all study parameters.

RESULTS

In base case analysis, BSC, SC, RFA and HR yielded LEs of 11.9, 23.1, 34.8 and 37.0 months, and QALEs of 7.8, 13.2, 22.0 and 25.0 months, respectively. Model results were sensitive to age, comorbidity, length of model simulation and utility after HR. Probabilistic sensitivity analysis showed increasing preference for RFA over HR with increasing patient age.

CONCLUSIONS

HR may be optimal for healthy 70-year-old patients with CLM. In older patients with comorbidities, RFA may provide better LE and QALE. Treatment decisions in older cancer patients should account for patient age, comorbidities, local expertise and individual values.

Biliary peritonitis after radiofrequency ablation diagnosed by gadoxetic acid-enhanced MR imaging

This study describes the first case of biliary peritonitis after radiofrequency ablation diagnosed by magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA), a hepatocyte-specific MR imaging contrast agent. The image acquired 300 minutes after the administration of Gd-EOB-DTPA was useful to make a definite diagnosis and to identify the pathway of bile leakage. It is important to decide on the acquisition timing with consideration of the predicted location of bile duct injury.

Small- and medium-sized hepatocellular carcinomas: monopolar radiofrequency ablation with a multiple-electrode switching system-mid-term results

PURPOSE

To prospectively assess the safety and mid-term therapeutic effectiveness of monopolar radiofrequency (RF) ablation with a multiple-electrode switching system for treating small- and medium-sized (≤ 5 cm) hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

The institutional review board approved this prospective study, and all patients gave informed consent. From February 2009 to January 2010, 166 patients (110 men and 56 women; age range, 38-86 years; mean age, 62 years ± 10 [standard deviation]) with 166 HCCs less than or equal to 5 cm in diameter were treated with monopolar RF ablation with a multiple-electrode switching system. One of three experienced radiologists performed the RF ablation. Technique effectiveness, ablation volume and time, and major complications were evaluated by means of computed tomography (CT) immediately after RF ablation and at follow-up CT examinations at 1 month and then every 3 months after the procedure. The overall survival, disease-free survival, and local tumor progression-free survival rates were evaluated by using the Kaplan-Meier method.

RESULTS

The technique effectiveness rate determined 1 month after RF ablation was 99.4%. Mean ablation parameters were as follows: volume, 85 cm(3) ± 54; maximum diameter, 61 mm ± 13; and minimum diameter, 43 mm ± 11. The major complication rate was 4.8%. The 6-month and 1-, 2-, and 3-year local tumor progression rates were 2%, 6%, 10%, and 11%, respectively. The overall survival rates at 1, 2, and 3 years after RF ablation were 99%, 97%, and 96%, and corresponding local tumor progression-free survival rates were 94%, 90%, and 89%, respectively. The disease-free survival rates at 1, 2, and 3 years after RF ablation were 75%, 60%, and 54%, respectively.

CONCLUSION

Monopolar RF ablation with a multiple-electrode switching system in small- and medium-sized HCCs was safe and efficient, and it provided successful local tumor control and high local tumor progression-free survival rates because an adequate ablation volume was obtained.

Effectiveness of impedance monitoring during radiofrequency ablation for predicting popping

AIM: To retrospectively evaluate the effectiveness of impedance monitoring for predicting popping during radiofrequency ablation (RFA) using internally cooled electrodes.

METHODS: We reviewed 140 patients (94 males, 46 females; age range 73.0 ± 11.1 year) who underwent RFA between February 2006 and November 2008 with a modified protocol using a limited power delivery rather than a conventional one to avoid popping. All the patients provided their written informed consent, and the study was approved by the institutional review board. Intraprocedural impedances were measured for the study subjects, and the tumors were classified into three types according to the characteristics of their impedance curves: increasing, flat, or decreasing. The tumors were further sorted into seven subtypes (A-G) depending on the curvature of the impedance curve’s increase or decrease. Relative popping rates were determined for the three types and seven subtypes. A chi-square test was performed to estimate statistical significance.

RESULTS: A total of 148 nodules treated by RFA were analyzed. The study samples included 132 nodules of hepatocellular carcinoma, 14 nodules of metastatic liver cancer, and two nodules of intrahepatic cholangiocarcinoma. The numbers of nodules with each impedance curve type were as follows: 37 increasing-type nodules, 43 flat-type nodules, and 68 decreasing-type nodules. Popping occurrence rates were 24.3%, 46.5% and 64.7%, respectively. Flat-type nodules exhibited a significantly higher rate of popping compared to increasing-type nodules (P = 0.039). Decreasing-type nodules exhibited a significantly higher rate of popping compared to increasing-type nodules (P < 0.0001). Notably, nodules that showed a sharp decrease in impedance in the latter ablation period (subtype E) exhibited a significantly higher rate of popping compared to other subtypes.

CONCLUSION: Intraprocedural impedance monitoring can be a useful tool to predict the occurrence of popping during liver tumor RFA performed with internally cooled electrodes.

Endoscopic Ultrasound-Guided Radiofrequency Ablation (EUS-RFA) of the Pancreas in a Porcine Model

Backgrounds. Limited effective palliative treatments exist for pancreatic cancer which includes surgery or chemotherapy. Radiofrequency ablation (RFA) uses high frequency alternating current to ablate diseased tissue and has been used to treat various tumors. In this study, we evaluated a prototype probe adjusted to the EUS-needle to perform EUS-RFA to permit coagulative necrosis in the pancreas. Methods. Five Yucatan pigs underwent EUS-guided radiofrequency ablation of the head of their pancreas. Using an EUS-needle, RFA was applied with 6 mm and then 10 mm of the probe exposed at specific wattage for preset durations. Results. Only one pig showed moderate levels of pancreatitis (20% proximal pancreatitis). The other animals showed much lower areas of tissue damage. In 3 of the 5 pigs, the proximal pancreas showed greater levels of tissue injury than the distal pancreas, consistent with the proximity of the tissue to the procedure site. In 1 pig, both proximal and distal pancreas showed minimal pancreatitis (1%). There was minimal evidence of fat necrosis in intra-pancreatic and/or extra-pancreatic adipose tissue. Conclusion. EUS-guided RFA of the pancreatic head with the monopolar probe through a 19-gauge needle was well tolerated in 5 Yucatan pigs and with minimal amount of pancreatitis.

Radiofrequency ablation of a solitary liver metastasis complicated by colonic perforation

Radiofrequency ablation is used for the treatment of primary liver malignancies and liver metastases. In this case, the authors performed percutaneous radiofrequency ablation of a solitary esophageal carcinoma metastasis within the left hepatic lobe. Following the procedure, the patient developed a colonic perforation with a large right upper quadrant abscess. Although the abscess nearly resolved after intravenous antibiotics and percutaneous drainage, the patient ultimately developed a colocutaneous fistula that required surgical excision and right hemicolectomy. The risks for developing this complication as well as measures to minimize this risk are discussed.

Comparison of radiofrequency ablation and resection for hepatic metastasis from colorectal cancer

BACKGROUND/AIMS

Radiofrequency ablation (RFA) has been mostly used as a therapeutic alternative to hepatic resection for treating liver metastasis of colorectal cancer. The purpose of the present study was to determine whether there were differences in outcome between RFA and surgical resection in the treatment of colorectal cancer with liver metastases.

METHODS

We performed a retrospective analysis of 53 patients who underwent only hepatic resection or only RFA for colorectal liver metastases. Twenty-five patients who underwent hepatic resection were compared with 28 patients who underwent RFA for synchronous or metachronous liver metastases.

RESULTS

The median CEA level at the time of diagnosis of liver metastases was significantly higher in the resection group (14.2 ng/mL vs. 2.8 ng/mL, p=0.002). The median size of main liver metastases was significantly larger in the resection group (4.0 cm vs. 2.05 cm, p=0.002). There was no difference in the percentage of patients experiencing major complication (one patient in each group). The marginal recurrence rate was significantly higher in the RFA group (p=0.004). Disease-free and overall survival were longer in the resection group (p=0.008 and 0.017, respectively). In multivariate analysis, only the type of treatment was a factor associated with disease-free and overall survival (p=0.004 and 0.007, respectively).

CONCLUSIONS

Because of the high marginal recurrence rate, RFA shows an inferior outcome in comparison with surgical resection. Therefore, RFA should be considered for only selected patients with unresectable (by any means) disease or with high operative risk.

Ki-67 is a prognostic biomarker of survival after radiofrequency ablation of liver malignancies

PURPOSE

To assess the predictive value of examinations of tissue adherent to multitined electrodes on local tumor progression-free survival (LPFS) and overall survival (OS) after liver tumor radiofrequency ablation (RFA).

METHODS

An institutional review board-approved, Health Insurance Portability and Accountability Act-compliant review identified 68 liver tumors treated with RFA in 63 patients with at least 3 years' follow-up. Tissue adherent to the electrode after liver tumor RFA was evaluated with proliferation (Ki-67) and apoptotic (caspase-3) markers. LPFS and OS were evaluated by Kaplan-Meier methodology and the log-rank test. Multivariate analysis assessed the effect of tumor size, pathology, and post-RFA tissue characteristics on LPFS and OS.

RESULTS

Post-RFA tissue examination classified 55 of the 68 tumors as completely ablated with coagulation necrosis, with cells positive for caspase-3 and negative for Ki-67 (CN). Thirteen had viable Ki-67-positive tumor cells. Mean liver tumor size was larger in the viable (V) group versus the CN group (3.4 vs. 2.5 cm, respectively; P = .017). For the V and CN groups, respectively, local tumor progression occurred in 12 (92 %) of 13 and 23 (42 %) of 55 specimens. One, 3-, and 5-year LPFS was 8 %, 8 %, and 8 %, and 79 %, 47 %, and 47 % (P < .001) for the V and CN groups, respectively. During a 63-month median follow-up, 92 % of patients in the V group and 58 % in the CN group died, resulting in 1-, 3-, and 5-year OS of 92 %, 25 %, and 8 % vs. 92 %, 59 %, and 33 % (P = .032), respectively.

CONCLUSIONS

Ki-67-positive tumor cells on the electrode after liver tumor RFA is an independent predictor of LPFS and OS. Size, initially thought to be an independent risk factor for local tumor progression in tumors 3-5 cm, does not hold its significance at long follow-up.

Bimodal electric tissue ablation (BETA) compared with the Cool-Tip RFA system

BACKGROUND

Bimodal electric tissue ablation (BETA) incorporates the process of electrolysis into radiofrequency ablation (RFA) to increase the size of tissue ablation. This study investigated whether BETA could increase the efficacy of the Cool-Tip RF system (Covidien, Boulder, CO, USA) to produce larger ablations. It also investigated whether applying electrolysis only during the pretreatment phase (called electrochemical treatment (ECT)/RFA group) is as effective as BETA (where electrolysis was used during both the pretreatment and RFA phases).

METHODS

A Cool-Tip RF system (Covidien) was used to test three types of ablations (RFA, BETA, and ECT/RFA) in a pig liver model. In BETA, 9 V of direct current was provided for 10 min, after which the RF generator was started and both electrical circuits were allowed to run concurrently. In ECT/RFA, however, the direct current circuit was switched off after 10 min of pretreatment and only RFA was performed as described above. Ablation sizes were measured in three dimensions.

RESULTS

The size of ablations (transverse diameter A and B) produced by BETA and ECT/RFA was significantly larger compared with standard RFA (P < 0/001). BETA also created larger ablations compared with ECT/RFA (P < 0.001).

CONCLUSION

BETA could improve the efficacy of the Cool-Tip RF system (Covidien) to achieve larger ablations. The increased tissue hydration improved delivery of electrical energy to the tissues and delayed the process of desiccation, thus allowing the ablation process to continue for longer periods of time to produce larger ablations. BETA could be used to treat larger liver tumours more effectively than standard RFA.

Multi-modality treatment of colorectal liver metastases

Liver metastases synchronously or metachronously occur in approximately 50% of colorectal cancer patients. Multimodality comprehensive treatment is the best therapeutic strategy for these patients. However, the optimal pattern of multimodality therapy is still controversial, and it raises several significant concerns. Liver resection is the most important treatment for colorectal liver metastases. The definition of resectability has shifted to focus on the completion of R0 resection and normal liver function maintenance. The role of neoadjuvant and adjuvant chemotherapy still needs to be clarified. The management of either progression or complete remission during neoadjuvant chemotherapy is challenging. The optimal sequencing of surgery and chemotherapy in synchronous colorectal liver metastases patients is still unclear. Conversional chemotherapy, portal vein embolization, two-stage resection, and tumor ablation are effective approaches to improve resectability for initially unresectable patients. Several technical issues and concerns related to these methods need to be further explored. For patients with definitely unresectable liver disease, the necessity of resecting the primary tumor is still debatable, and evaluating and predicting the efficacy of targeted therapy deserve further investigation. This review discusses different patterns and important concerns of multidisciplinary treatment of colorectal liver metastases.

Comparative assessment of the safety and effectiveness of radiofrequency ablation among elderly medicare beneficiaries with hepatocellular carcinoma

BACKGROUND

Radiofrequency ablation (RFA) use among patients with hepatocellular carcinoma (HCC) has increased dramatically over the last decade, but assessments outside specialized centers are lacking. This population-based study was intended to evaluate the safety and effectiveness of RFA when used to treat HCC.

METHODS

A cohort study of HCC patients (diagnosed 2002-2005) was performed using linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data. Early (≤90-day) mortality and readmission as well as survival among patients undergoing RFA, resection, or no treatment were compared using multivariate and propensity score adjusted Poisson and Cox regression models.

RESULTS

Of 2631 patients (mean age 76.1±6.1 years, 65.9% male), 16% underwent RFA (49.6%) or resection (50.4%). Early mortality (13.6 vs. 18.7%, P=.16) and readmission (34.5 vs. 32.1%, P=.60) rates were similar among RFA and resection patients. The 1-year survival after RFA and resection was similar (72.2 vs. 79.7%, P=.18), but beyond 3 years there was a survival benefit among patients undergoing resection (39.2 vs. 58.0%, P<.001). Patients treated with RFA as a sole therapeutic intervention in the 1st year had a similar hazard of death compared with untreated patients (hazard ratio [HR] 0.84, 95% confidence interval [95% CI] 0.54-1.33).

CONCLUSIONS

In the general community, patients treated with RFA have a similar risk of early adverse events compared with those treated with resection with no clear survival benefit when used as a sole intervention. Although RFA has been described as a safe and effective treatment for HCC at specialized centers, this experience may not extrapolate to the general community and requires further evaluation.

Mortality and complication rates of percutaneous ablative techniques for the treatment of liver tumors: a systematic review

OBJECTIVES

Reported rates of major complications and mortality of radiofrequency ablation (RFA), microwave ablation (MWA) and percutaneous ethanol injection (PEI) for the treatment of liver tumours were substantially heterogeneous among studies. The aim was to analyse the mortality and major complication rates of percutaneous RFA, PEI and MWA.

METHODS

MEDLINE and EMBASE search from January 1982 to August 2010. Randomised clinical trials and observational studies, age >18, more than 50 patients for each technique analysed, studies reporting mortality and major complications were included. Random effects model was performed, with assessment for heterogeneity and publication bias.

RESULTS

Thirty-four studies including 9531, 1185, and 1442 patients for RFA, MWA, and PEI, respectively were included. For all ablative techniques pooled proportion mortality rate was 0.16% (95% confidence interval [CI], 0.10-0.24). Pooled mortality rate associated with RFA, PEI and MWA was 0.15% (0.08-0.23), 0.59% (0.14-1.3) and 0.23% (0.0-0.58) respectively. Pooled proportion of major complications was 3.29% (2.43-4.28). Major complication rates associated with RFA, MWA, and PEI was 4.1% (3.3-5.1), 4.6% (0.7-11.8) and 2.7% (0.28-7.4) respectively.

CONCLUSIONS

Percutaneous RFA, PEI and MWA can be considered safe techniques for the treatment of liver tumours.

Systematic review and meta-analysis of survival and disease recurrence after radiofrequency ablation for hepatocellular carcinoma

BACKGROUND

Despite being one of the commonest causes of cancer-related death around the world, only 20 per cent of hepatocellular carcinomas (HCCs) are amenable to curative treatment (surgical resection or liver transplantation). Radiofrequency ablation (RFA) has emerged as a popular therapy for unresectable HCC. There is evidence that the disparity in survival after curative RFA and surgery for HCC, especially tumours smaller than 3 cm in diameter, is narrowing. This review examined the survival and disease recurrence rates after RFA for HCC over the past decade.

METHODS

A systematic review was conducted using MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Cochrane Methodology Register and the Database of Abstracts of Reviews of Effects from January 2000 until November 2010. Papers reporting on patients with HCC who were treated with RFA, either in comparison or in combination with other interventions, such as surgery or percutaneous ethanol injection (PEI), were eligible for inclusion. Outcome data collected were overall survival, disease-free survival and disease recurrence rates. Only randomized controlled trials (RCTs), quasi-RCTs and non-randomized comparative studies with more than 12 months' follow-up were included.

RESULTS

Forty-three articles, including 12 RCTs, were included in the review. The majority of the articles reported the use of RFA for unresectable HCC, often in combination with other treatments such as PEI, transarterial chemoembolization and/or surgery. Overall and disease-free survival rates continue to improve, despite an increase in the size and numbers of tumours treated. More recently some clinicians have used RFA to treat selected patients with resectable HCC, with good outcomes.

CONCLUSION

RFA provides a valuable treatment option for patients with unresectable HCC. It improves survival in those previously considered to have advanced disease. As progress continues to be made, RFA is gradually being used to treat resectable HCC.

Radioablation settings affecting the size of lesions created ex vivo in porcine livers with monopolar perfusion electrodes

RATIONALE AND OBJECTIVES

To explore the morphological characteristics of ablated lesions and find which combination of duration, temperature, and power was preferable to create largest lesion size with monopolar perfusion electrodes.

MATERIALS AND METHODS

Using monopolar perfusion electrodes to create 72 lesions in 30 excised porcine livers with radiofrequency radiation at different durations (5, 10, 15, and 20 minutes), temperatures (83 degrees C, 93 degrees C, 103 degrees C, and 113 degrees C), and powers (20, 30, and 40 W). Lesion volumes were calculated from longitudinal diameters and transverse diameters. Morphological characteristics were assessed microscopically from slides stained with hematoxylin and eosin.

RESULTS

Positive correlations were found between duration and longitudinal diameter (r = 0.66; P < .001), transverse diameter (r = 0.66; P < .001), distance of ablation beyond the electrode tip (r = 0.56; P < .001), and volume of lesions (r = 0.66; P < .001). Temperature was also positively correlated with longitudinal diameter (r = 0.70; P < .001), transverse diameter (r = 0.72; P < .001), distance of ablation beyond the electrode tip (r = 0.61; P < .001), and lesion volume (r = 0.711; P < .001). Lesion size did not increase when duration was longer than 15 minutes and temperature was higher than 103 degrees C. Power was not correlated with lesion size. Lesion size did not increase with increasing power. Macroscopically, all lesions were elliptical in cross section and appeared three zones: a central zone (I), a coagulated necrotic zone (II), and a hemorrhagic and edematous zone (III) from inside to outside. Microscopically, cells morphology and the nucleus were irregular or even disappeared in zone I. In zone II and III, cells did not appear deformation.

CONCLUSION

Duration and temperature, not power, affected lesion size. The largest lesion size was about 3.5 cm x 2.5 cm x 2.5 cm as temperature and duration was 15 minutes/103 degrees C.

Quality initiatives: strategies for anticipating and reducing complications and treatment failures in hepatic radiofrequency ablation

Radiofrequency (RF) ablation is one of several local treatment strategies that can be used for the destruction of a variety of primary and secondary liver tumors. As experience with RF ablation grows, it becomes increasingly evident that successful ablation requires meticulous technique. In addition, knowledge of potential complications is critical for both the interventionalist and the radiologist, whose postablation interpretation can facilitate identification of complications and treatment failures. Hepatic RF ablation offers significant advantages in that it is less invasive than surgery and carries a low risk of major complications. Successful prevention of complications and treatment failures begins at initial consultation and continues with preablation evaluation of specific patient factors such as coagulation profiles, use of medications, and risk factors for infection. Other predisposing factors include background liver cirrhosis, prior hepatectomy, and portal hypertension. During ablation, careful attention must be given to tumor size, number, and location. For large or multiple ablations, separate ablation sessions can help reduce the prevalence of postablation syndrome, and clustered electrodes and multiple overlapping treatment zones may be used to reduce the risk of treatment failure. It is critical to reevaluate tumors during ablation to determine the best approach and to compensate for changes in size and relative location due to patient positioning. With use of these strategies, hepatic RF ablation can be performed with greater safety, better patient tolerance, and a reduced risk of complications and treatment failures.

Hemorrhagic complications of percutaneous radiofrequency ablation for liver tumors

BACKGROUND

Although radiofrequency ablation (RFA) is widely accepted as a percutaneous treatment for liver tumors; serious complications may occur resulting in 0.1% to 0.5% mortality. This study analyzed the risk factors and management of hemorrhagic complications, such as hemoperitoneum, hemothorax, and hemobilia.

METHODS

We performed 4133 RFA treatments in 2154 patients with primary and metastatic liver tumors from February 1999 to December 2007. Of these, we enrolled patients with hemorrhagic complications and reviewed their medical records thoroughly. The risk factors for each hemorrhagic complication were analyzed using unconditional logistic regression.

RESULTS

Hemorrhagic complications occurred in 63 out of 4133 treatments (1.5%), including hemoperitoneum in 29 (0.7%), hemothorax in 14 (0.3%), and hemobilia in 20 (0.5%). Eleven, 8, and 4 of these patients, respectively, were categorized as major complications requiring blood transfusion or drainage. Two patients died after hemoperitoneum. Logistic regression analysis revealed large tumor size [odds ratio (OR) 1.06 per 1 mm increase in diameter] and low platelet count (OR 0.88 per 10,000/microL increase) were significant risk factors for hemoperitoneum. The location of tumor nodules was a significant risk factor for hemothorax (segment 7, OR 2.31) and hemobilia (segment 1, OR 3.30). Other factors, including the number of needle insertions or the duration of ablation, were not significant.

CONCLUSIONS

Although hemorrhagic complications were relatively rare with percutaneous RFA, specific treatments, such as blood transfusion and drainage, were required in some cases. Care must be taken, especially in high-risk patients.

Strategies for treating liver metastasis from gastric cancer

The prognosis of patients with liver metastasis from gastric cancer is dismal. This article reviews the characteristics of gastric cancer metastasizing to the liver, and multimodality of treatments. Differentiated adenocarcinoma, poorly differentiated adenocarcinoma with a medullary growth pattern, and special types, including endocrine carcinoma and hepatoid carcinoma, are likely to metastasize to the liver. The overexpression of growth factors or adhesion molecules is clinically significant for liver metastasis. Surgery for liver metastases arising from gastric adenocarcinoma is reasonable if a complete resection seems feasible after careful preoperative staging. A hepatic resection should always be considered as an option for gastric cancer patients with hepatic metastases. Newer generation cytotoxic agents such as S-1, irinotecan, and taxanes show promising activity for patients with metastases. Adjuvant chemotherapy or molecular targeted therapy will provide significant benefits to patients in the future.

American Society of Clinical Oncology 2009 clinical evidence review on radiofrequency ablation of hepatic metastases from colorectal cancer

PURPOSE

To review the evidence about the efficacy and utility of radiofrequency ablation (RFA) for hepatic metastases from colorectal cancer (CRHM).

METHODS

The American Society of Clinical Oncology (ASCO) convened a panel to conduct and analyze a comprehensive systematic review of the RFA literature from Medline and the Cochrane Collaboration Library.

RESULTS

Because data were considered insufficient to form the basis of a practice guideline, ASCO has instead published a clinical evidence review. The evidence is from single-arm, retrospective, and prospective trials. No randomized controlled trials have been included. The following three clinical issues were considered by the panel: the efficacy of surgical hepatic resection versus RFA for resectable tumors; the utility of RFA for unresectable tumors; and RFA approaches (open, laparoscopic, or percutaneous). Evidence suggests that hepatic resection improves overall survival (OS), particularly for patients with resectable tumors without extrahepatic disease. Careful patient and tumor selection is discussed at length in the literature. RFA investigators report a wide variability in the 5-year survival rate (14% to 55%) and local tumor recurrence rate (3.6% to 60%). The reported mortality rate was low (0% to 2%), and the major complications rate was commonly reported to be between 6% and 9%. RFA is currently performed with all three approaches.

CONCLUSION

There is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as OS for patients with CRHM. Clinical trials have established that hepatic resection can improve OS for patients with resectable CRHM.

Radiofrequency ablation for metachronous hepatic metastases from gastric cancer

The objective of this study was to evaluate the results of radiofrequency ablation (RFA) for the treatment of metachronous hepatic metastases from gastric adenocarcinoma. Between January 2000 and February 2008, we retrospectively reviewed 7 cases for which RFA was performed for treating metachronous hepatic metastases after resection of the primary gastric adenocarcinoma. The median period between curative gastrectomy and metachronous hepatic metastasis was 14 months (range: 6 to 48 mo). The median survival of the patients was 11.0 months (range: 5.5 to 39.2) after the first detection of hepatic metastases and 10.0 months (range: 5 to 38.2) after the first RFA. Hepatic metastases recurred 3 to 21 months after RFA in all patients. A second RFA was performed for a single recurrent hepatic metastasis in 1 patient and this patient survived more than 3 years without recurrence until the time of this study. In conclusion, the efficacy of RFA alone for metachronous hepatic metastases from gastric adenocarcinoma was disappointing due to multiple intrahepatic recurrences. Combination therapy such as systemic chemotherapy or hepatic arterial infusion chemotherapy adjuvant to RFA would more reasonable for treating hepatic metastases from gastric cancer.

EUS-guided radiofrequency ablation with a prototype electrode array system in an animal model (with video)

BACKGROUND

Although previously reported in an animal model, the development of EUS-guided radiofrequency ablation (EUS-RFA) has been impeded because of a lack of a retractable needle electrode array that could safely and effectively ablate large areas.

OBJECTIVE

To evaluate the feasibility and safety of performing EUS-RFA with a 19-gauge FNA needle fitted with an umbrella-shaped retractable needle electrode array.

DESIGN AND SETTING

Endoscopic experimental study in a porcine survival model at a tertiary referral center animal laboratory.

MAIN OUTCOME MEASURES

Evaluate the safety and efficacy of the retractable needle electrode array for performing EUS-RFA.

INTERVENTIONS

A 19-gauge EUS-FNA needle was modified and fitted with a retractable echogenic umbrella-shaped monopolar electrode array at its tip. The FNA needle was connected to a 200-W generator that has an impedance-based feedback system. EUS-RFA of the liver was attempted on 5 Yorkshire pigs. Although 1 pig was euthanized immediately after RFA to assess for immediate complications and pathological examination, the 4 others were kept alive for 7 days.

RESULTS

At EUS, the needle electrode was well visualized and could be deployed in the liver without technical difficulty. During ablation, a round hyperechoic focus gradually surrounded the electrode tip. Tissue ablation was attained within 7 minutes, and the electrode array could be easily withdrawn into the needle assembly. The vital signs of all pigs remained stable throughout the procedure and until they were euthanized. Histopathology in all pigs revealed a discrete, well-demarcated spherical focus of complete coagulation necrosis measuring 2.6 cm in diameter and without damage to the surrounding liver parenchyma or vasculature.

CONCLUSIONS

In this experimental study, EUS-RFA of the liver was performed safely by using the retractable umbrella-shaped electrode array with effective coagulation necrosis of large areas.

CT-guided radiofrequency ablation for hepatocellular carcinomas that were undetectable at US: therapeutic effectiveness and safety

PURPOSE

To determine the therapeutic effectiveness and safety of computed tomography (CT)-guided radiofrequency (RF) ablation for hepatocelluar carcinomas (HCCs) that were undetectable at ultrasonography (US).

MATERIALS AND METHODS

CT-guided RF ablation with use of internally cooled electrodes was performed in 66 patients with 97 HCCs (diameter range, 3-39 mm) in 78 sessions. Two radiologists retrospectively evaluated in consensus the presence or absence of local tumor progression as well as the complications at CT performed immediately after RF ablation and at 1-, 3-, 6-, and 12-month follow-up. The relationship between the occurrence of pneumothorax and the electrode length in the lung in patients treated with the transpulmonary approach was statistically evaluated with use of the Mann-Whitney test.

RESULTS

The technical success rate of CT-guided RF ablation immediately after RF ablation was 97% (94 of 97 HCCs). The primary technique effectiveness rates of complete ablation 1, 3, 6, and 12 months after RF ablation were 97% (94 of 97 HCCs), 94% (91 of 97 HCCs), 84% (81 of 96 HCCs), and 74% (66 of 89 HCCs), respectively. Major complications were observed in six of the 78 treatment sessions (7.7%). In five of these six sessions, pneumothorax developed immediately after RF ablation; the remaining complication was tumor seeding along the electrode tract. Self-limiting pneumothorax was observed in 12 of 38 sessions (32%) in which the transpulmonary approach was used. The electrode length in the lung was not statistically related to the occurrence of pneumothorax (P = .26).

CONCLUSIONS

For HCCs that are undetectable at US, CT-guided RF ablation is effective and relatively safe.

Percutaneous radiofrequency ablation for the hepatocellular carcinoma abutting the diaphragm: assessment of safety and therapeutic efficacy

Objective

To assess the safety and therapeutic efficacy of a percutaneous radiofrequency (RF) ablation for the hepatocellular carcinoma (HCC) abutting the diaphragm.

Materials and Methods

We retrospectively assessed 80 patients who underwent a percutaneous RF ablation for a single nodular (< 4 cm) HCC over the last four years. Each patient underwent an ultrasound-guided RF ablation using internally cooled electrodes for the first-line treatment. We divided patients into two subgroups based on whether the index tumor was abutting (less than 5 mm) the diaphragm or not: group A (abutting; n = 31) versus group B (non-abutting; n = 49). We compared the two subgroups for complications and therapeutic efficacy using image and the review of medical records. The statistical assessment included an independent t-test, Fisher's exact test, and chi-square test.

Results

The assessment of the diaphragmatic swelling at CT immediately following the procedure was more severe in group A than group B (mean thickness change:1.44 vs. 0.46 mm, p = 0.00). Further, right shoulder pain was more common in group A than B (p = 0.01). Although minor complications (hemothorax 1 case, pleural effusion 1 case) were noted only in group A, no major thoracic complication occurred in either group. The technical success rate was lower in group A than group B (84% vs. 98%, p = 0.03). As well, the primary and secondary technique effectiveness rates in group A and group B were 90% versus 98% (p = 0.29) and 79% versus 91% (p = 0.25), respectively. The local tumor progression rate was higher in group A than in group B (29% vs. 6%, p = 0.02).

Conclusion

We found that the percutaneous RF ablation for the HCC abutting the diaphragm is a safe procedure without major complications. However, it is less effective with regard to technical success and local tumor control.

Radiofrequency ablation for hepatic metastasis from gastric adenocarcinoma

The prognosis for gastric cancer with liver metastasis continues to be poor. We present our preliminary findings from 4 cases of liver metastasis from gastric adenocarcinomas treated using radiofrequency ablation (RFA). Between 1995 and 2004, the clinical history and course of 4 patients who underwent radiofrequency ablation for liver metastases from gastric cancer were reviewed. Two patients with smaller metachronous metastasis are currently alive without recurrence at 16 and 14 months and the other patients with larger synchronous metastatic lesions died after 4 and 12 months after RFA. Although this study was limited to a few cases and had a short follow-up duration, our findings suggest that RFA may provide an alternative treatment modality for liver metastasis resulting from gastric adenocarcinoma. Additional study is needed with a larger group of patients and longer follow up to evaluate the efficacy of RFA.

Histopathologic and immunohistochemical features of tissue adherent to multitined electrodes after RF ablation of liver malignancies can help predict local tumor progression: initial results

PURPOSE

To determine whether histopathologic and immunohistochemical features of tissue adherent to electrodes after radiofrequency (RF) ablation of liver malignancies can help predict local tumor progression (LTP).

MATERIALS AND METHODS

Institutional review board waiver and informed consent were obtained. Histologic and immunohistochemical examinations of tissue adherent to electrodes after RF ablation of liver malignancies were performed, with application of proliferation (Ki-67) and apoptosis (caspase-3) markers. Clinical and technical information were prospectively collected for an HIPAA-registered database. Medical records and imaging were reviewed to determine LTP for treated tumors smaller than 5 cm in diameter. LTP-free and survival rates were assessed with Kaplan-Meier method; differences between groups assessed with permutation log-rank test. Multivariate analysis assessed with Cox regression for factors related to LTP.

RESULTS

Sixty-eight malignant tumors treated with RF ablation were identified. Fifty-five tissue specimens were classified as coagulation necrosis (CN), thermal artifact only, or tumor cells positive for caspase-3/negative for Ki-67; and 13 as viable tumor cells (Ki-67 positive). Mean tumor size was larger in viable (3.4 cm) than in CN (2.5 cm) group before treatment (P = .01). For viable and CN groups, LTP occurred in 12 (92%) of 13 and 16 (29%) of 55 specimens, respectively; 1-year LTP-free rates were 0% and 74%, respectively (P < .001). Multivariate analysis confirmed that viable cells comprise independent risk factor for LTP (P < .001). The odds of LTP is six times greater in viable group compared with CN group for tumors 3-5 cm (hazard ratio: 5.9, 95% confidence interval: 2.4, 14.5) and 10 times greater for tumors smaller than 3 cm (hazard ratio: 10.1, 95% confidence interval: 1.7, 57.5). Median survival was 32.7 months.

CONCLUSION

Evidence of Ki-67-positive tumor cells on the electrode after hepatic RF ablation is an independent predictor of LTP.

Radiofrequency ablation prior to liver transplantation: focus on complications and on a rare but severe case

BACKGROUND

Radiofrequency ablation (RFA) is an established treatment for hepatocellular carcinoma (HCC) in patients awaiting liver transplantation, due to its comparably low rate of complication and high effectiveness. Complications are thought to be rare and mostly self-limiting. By contrast, we report on a life-threatening complication and discuss it in the context of other complications.

PATIENTS AND METHODS

Out of a total of 149 RFA procedures, the incidence of major complications was 4% on a per-procedure basis. Mortality was 0.67%. Major complications included intractable pain, intrahepatic hematoma, skinburn at the site of patch electrode, and sectorial bile duct stricture. All complications occurred after percutaneous RFA. Highlighted is a young patient listed for liver transplantation because of HCC recurrence following hepatic resection, who was treated by percutaneous RFA as a bridging therapy until a suitable graft became available. Post-operatively, gastric perforation occurred due to heat injury of the gastric wall.

CONCLUSIONS

The percutaneous RFA approach can occasionally lead to detrimental complications, particularly in patients with intra-abdominal adhesions, due to previous surgery if new intrahepatic malignant lesions accrue near the resection margin. Even widespread HCC disease can be treated effectively with orthotopic liver transplantation if the tumor growth is limited to the liver.