[Radiofrequency ablation of liver metastases. Technique and initial results]

Ablation therapy of hepatocellular carcinoma: a comparative study between radiofrequency and microwave ablation

PURPOSE

The aim of the study is to retrospectively evaluate and compare the therapeutic response of Radiofrequency (RF) and Microwave (MW) ablation therapy of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

53 consecutive patients (42 males, 11 females; mean age 59 years, range: 40-68, SD: 4.2) underwent CT-guided percutaneous RF and MW ablation of 68 HCC liver lesions. The morphologic tumor response (number, location and size) was evaluated by magnetic resonance imaging. The follow-up protocol was 24 h post-ablation then within 3 monthly intervals post-ablation in the first year and 6 monthly intervals thereafter.

RESULTS

Complete therapeutic response was noted in 84.4% (27/32) of lesions treated with RFA and in 88.9% (32/36) of lesions treated with MW ablation (P = 0.6). Complete response was achieved in all lesions ≤2.0 cm in diameter in both groups. There was no significant difference in rates of residual foci of HCC lesions between RF and MW ablation groups (P = 0.15, Log-rank test). Recurrence rate for 3, 6, 9, and 12 months in patients with HCC who underwent RF ablation compared with MW ablation were 6.3%, 3.1%, 3.1% versus 0%, 5.6%, 2.8%, and 2.8%. Progression-Free Survival rates for treated patients with RF ablation of 1, 2, and 3 years were 96.9%, 93.8%, and 90.6% and treated with MW ablation therapy were 97.2%, 94.5%, and 91.7, respectively (P = 0.98).

CONCLUSION

In conclusion, RF and MW ablation therapy showed no significant difference in the treatment of HCC regarding the complete response, rates of residual foci of untreated disease, and recurrence rate.

Radiofrequency ablation as a treatment tool for liver metastases of colorectal origin

At diagnosis 10–25% of patients with colorectal liver metastases (CRLM) present as resectable disease. Liver resection is the gold standard treatment, resulting in a 5-year overall survival (OS) of 22–58%, local recurrence rates of 1.2–10.4% and a perioperative mortality of less than 5%. Multiple attempts have been made to assess the possible contribution of radiofrequency ablation (RFA) to improve OS and progression-free survival (PFS) in patients with unresectable colorectal liver metastases. The aim of this paper is to review the RFA literature in the setting of colorectal liver metastases: RFA with and without chemotherapy, RFA with and without resection, RFA for solitary unresectable CRLM, surgical and percutaneous imaging-guided RFA, RFA compared with chemotherapy. The reported OS, PFS, local recurrence rates, morbidity and mortality in these different settings are analyzed. This paper reflects on a possible role of RFA in resectable CRLM.

Quality improvement guidelines for radiofrequency ablation of liver tumours

The development of image-guided percutaneous techniques for local tumour ablation has been one of the major advances in the treatment of liver malignancies. Among these methods, radiofrequency ablation (RFA) is currently established as the primary ablative modality at most institutions. RFA is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma (HCC) when liver transplantation or surgical resection are not suitable options [1, 2]. In addition, RFA is considered a viable alternate to surgery (1) for inoperable patients with limited hepatic metastatic disease, especially from colorectal cancer, and (2) for patients deemed ineligible for surgical resection because of extent and location of the disease or concurrent medical conditions [3]. These guidelines were written to be used in quality-improvement programs to assess RFA of HCC and liver metastases. The most important processes of care are (1) patient selection, (2) performing the procedure, and (3) monitoring the patient. The outcome measures or indicators for these processes are indications, success rates, and complication rates.

Liver tumor ablation: percutaneous and open approaches

The global incidence of liver cancer is greater than a million cases a year. Surgical resection where applicable is still the standard of care for these patients. Various liver-directed regional therapies have been developed in an effort to treat the vast majority of unresectable liver tumors. This article reviews the principles behind various ablation therapies currently available for malignant liver tumors and their outcomes.

Image-guided radiofrequency ablation (RFA) of spinal tumors

PURPOSE

To evaluate retrospectively the efficacy and safety of radiofrequency ablation (RFA) in patients with spinal tumors.

MATERIALS AND METHODS

Forty-one patients (25 men, 16 women; age range, 46-82 years) with nonresectable primary or secondary tumor involvement of the spine unresponsive to chemo- and radiotherapy received RFA treatment. Two radiofrequency ablation systems, one with a cool-tip electrode and one with an expandable electrode catheter, were used. Both systems work impedance controlled with a power output of 150- 200 W. Each coagulation cycle lasted 12-15 min depending on tumor impedance. Several single RFA cycles of 15 min each were used for overlapping RFAs in tumors with diameters of more than 3 cm. Temperature was kept between 50 degrees C and 120 degrees C and was chosen according to spinal cord distance and patient heat tolerance during the ablation. Multi-slice computed tomography (CT) combined with C-arm fluoroscopy guided the intervention. Efficacy outcomes were assessed after about 6 weeks, 6 months, and more than 6 months using standardized questionnaires and indices regarding tumor pain, pain disability, functional activities, quality of life, neurological status, and tumor progression.

RESULTS

RFA significantly reduced tumor-induced pain within 6 weeks, improved daily activities, and maintained quality of life. Mean time to tumor progression was 730+/-54 days (Kaplan-Meier estimate). No RFA-associated complications were reported.

CONCLUSION

RFA of primary and secondary spinal tumors, which were unresponsive to chemo- and radiotherapy and prone to progression, is a safe, resource-saving, and highly effective percutaneous technique in patients with nonresectable spinal tumors.

3D soft tissue imaging with a mobile C-arm

We introduce a clinical prototype for 3D soft tissue imaging to support surgical or interventional procedures based on a mobile C-arm. An overview of required methods and materials is followed by first clinical images of animals and human patients including dosimetry. The mobility and flexibility of 3D C-arms gives free access to the patient and therefore avoids relocation of the patient between imaging and surgical intervention. Image fusion with diagnostic data (MRI, CT, PET) is demonstrated and promising applications for brachytherapy, RFTT and others are discussed.

[Transarterial chemoembolization of liver metastases of colorectal carcinoma using degradable starch microspheres (Spherex): personal investigations and review of the literature]

Since two decades transarterial chemoembolization (TACE) of liver metastases has been investigated in numerous studies. However, no standardized therapeutic procedure exists so far. The present study retrospectively investigated survival, response and side effects after TACE of liver metastases in 21 patients with colorectal cancer and results are compared with previous literature. A total of 68 TACE procedures were performed. A suspension of degradable starch microspheres (DSM, Spherex) and Mitomycin C was applied selectively into hepatic arteries via a transfemoral approach. DSM effect a temporary arterial occlusion. Follow-up studies were performed by contrast enhanced spiral computed tomography (CT). The median survival was 13.8 months. Therapeutic response (according to WHO) was observed only in three patients. The progression free interval was 5.8 months. Patients developed a postembolization-syndrome (abdominal pain, fever, nausea) and increased transaminases in 27-43% of all interventions. A gastric ulcer occurred after four, cholecystitis after two TACE. As already shown in most previous studies, regardless of the used agents, also this investigation underlines the moderate therapeutic effect of TACE on colorectal liver metastases. So far, no significant survival benefit has been shown in the literature and the response rates are rather limited. In general, complications of TACE seem to be rare, but should not to be underestimated. Compared to TACE with long or permanent arterial occlusion, postembolization syndrome seems to be less pronounced using DSM. As TACE is rather a palliative therapeutic approach, DSM therefore might be more suited. Further studies on TACE of liver metastases should focus on to the patients' quality of life.

Stereotaktische Strahlentherapie von Lebermetastasen

Advances in radiation oncology made possible the locally curative treatment approach of stereotactically guided radiation therapy of liver tumours. Results of this highly focussed therapy were published by only a few centres. The radiation dose is delivered in one or a few fractions with high single doses. All published results show high local tumour control with low treatment morbidity. The treatment results of this noninvasive technique are similar to those of minimally invasive ablative therapies. Our own and other published data are summarized and discussed. The long-term results of this technique are currently being evaluated in a prospective multicentre trial.

[Current status of MRI diagnostics with liver-specific contrast agents. Gd-EOB-DTPA and Gd-BOPTA]

The contrast agents Gd-EOB-DTPA and Gd-BOPTA can be administered by bolus injection and are appropriate for use in MRI both as vascularization markers and markers of hepatobiliary excretion. This contribution presents an overview of the specific characteristics of contrast media and the status of clinical development. In comparison to CT and to MRI with unspecific extracellular Gd-chelates, liver-specific contrast agents offer advantages in differentiating unclear liver lesions, increasing the detection rate, and examining the bile duct system.

Percutaneous radiofrequency ablation of hepatic colorectal metastases: technique, indications, results, and new promises

Surgical resection is the standard of care for colorectal metastases isolated to the liver. However, only 10-25% of the patients are eligible for resection because of extent and location of the disease in the liver or concurrent medical conditions. Image-guided radiofrequency (RF) ablation is a minimally invasive technique that is emerging as a viable alternate treatment of nonsurgical patients with limited hepatic metastatic disease. Several series have shown that RF ablation can result in complete tumor eradication in properly selected candidates and have provided indirect evidence that the treatment improves survival. In a recent multicenter trial including 423 patients, overall survival of RF-ablation treated patients reached 47% at 3 years and 24% at 5 years. RF ablation technology is undergoing continuous improvement, and its clinical application has been successfully expanded to the treatment of colorectal metastases to the lung. Randomized trials comparing RF ablation with either surgical resection or chemotherapy protocols, however, are still missing. In this article, we review technique, indications, clinical results, and future prospects of RF ablation in the therapeutic management of metastatic colorectal cancer patients.

[Percutaneous radiofrequency ablation of liver cell carcinoma: a current overview]

In patients with hepatocellular carcinoma (HCC) surgical resection so far offers potential cure. Due to the frequent association with liver cirrhosis less then 30% of patients with HCC can be resected. In unresectable cases, radiofrequency ablation (RFA) offers an effective treatment alternative. Substantial improvements in the development of powerful generators (up to 250 W) combined with expandable, closed or open-perfused needle electrodes, provide coagulation necroses up to 5 cm in diameter. Most recently primary technical success rates of 85 to 100% were reported. Following RFA of HCC's (diameter up to 2,8 cm) 1-, 2-, 3 and 5-year survival was reported to be 97, 89, 71 and 48%. Low complication rates of 0-12% and a mortality of 0-1% indicate the minimal-invasive character of RFA. Basic principles, technique, indications, contraindications and limitations of percutaneous RFA will be discussed together with a presentation of own cases and a review of literature.

Aktueller Stand der Radiofrequenzablation von Lebertumoren

INTRODUCTION

Radio frequency ablation (RFA) represents a new technique for local destruction of liver tumors. Indication and procedure are poorly validated at present.

METHOD

To record the actual nationwide RFA application in Germany, a survey of 2026 hospitals with standardized questionnaires was conducted.

RESULTS

With a respond rate of 17.5%, results from 58 hospitals covering 1700 ablated patients were analyzed. In 25.9% of them, RFA is already used in potentially curative resectable tumors, in 22.4% even when incomplete ablation for tumor mass reduction is expected. Of the 58 hospitals, 75% combine resection and RFA to reach a so-called R-0 situation. The maximal tumor sizes they quoted for achieving complete ablation ranged from <3 cm to 11 cm. In contraindications for RFA, the tumor size, number of tumors, critical localization of the tumor, and disorders of liver function were mentioned the most.

CONCLUSION

This survey documents significant discrepancies in indication, application, procedure, and results in RFA for liver tumors. The lack of general standards and an overestimation of the method may lead to uncritical application, neglect of standard therapy, or unsatisfying results.

Complications of radiofrequency coagulation of liver tumours

BACKGROUND

Radiofrequency coagulation (RFC) is being promoted as a novel technique with a low morbidity rate in the treatment of liver tumours. The purpose of this study was to assess critically the complication rates of RFC in centres with both large and limited initial experience, and to establish causes and possible means of prevention and treatment.

METHODS

This is an exhaustive review of the world literature (articles and abstracts) up to 31 December 2001; 82 independent reports of RFC of liver tumours were analysed.

RESULTS

In total, 3670 patients were treated with percutaneous, laparoscopic or open RFC. The mortality rate was 0.5 per cent. Complications occurred in 8.9 per cent: abdominal bleeding in 1.6 per cent, abdominal infection in 1.1 per cent, biliary tract damage in 1.0 per cent, liver failure in 0.8 per cent, pulmonary complications in 0.8 per cent, dispersive pad skin burn in 0.6 per cent, hepatic vascular damage in 0.6 per cent, visceral damage in 0.5 per cent, cardiac complications in 0.4 per cent, myoglobinaemia or myoglobinuria in 0.2 per cent, renal failure in 0.1 per cent, tumour seeding in 0.2 per cent, coagulopathy in 0.2 per cent, and hormonal complications in 0.1 per cent. The complication rate was 7.2, 9.5, 9.9 and 31.8 per cent after a percutaneous, laparoscopic, simple open and combined open approach respectively. The mortality rate was 0.5, 0, 0 and 4.5 per cent respectively.

CONCLUSION

The morbidity and mortality of RFC, while low, is higher than previously assumed. With adequate knowledge, many complications are preventable.