Small hepatocellular carcinoma: therapeutic effectiveness of percutaneous radio frequency ablation therapy with a LeVeen needle electrode

Various complications of percutaneous radiofrequency ablation for hepatic tumors: radiologic findings and technical tips

Radiofrequency ablation is a safe and effective treatment for primary and secondary liver malignancies and has a low complication rate; however, there are various radiofrequency ablation-related complications which can occur from the thorax to the pelvis. Although most of these complications are usually minor and self-limited, they may become fatal if diagnosis and treatment are delayed. It is important for radiologists performing radiofrequency ablation to have a perspective regarding the possible radiofrequency ablation-related complications and their risk factors as well as the radiologic findings for their timely detection and increase of the treatment efficacy, and thereby encouraging the use of the radiofrequency ablation technique. This article illustrates the various imaging features of common and rare radiofrequency ablation-related complications as well as offers technical tips in order to avoid these complications.

Percutaneous ablation for small hepatocellular carcinoma

Hepatocellular carcinoma is increasingly detected at small size, usually 5 cm or smaller in diameter. For small hepatocellular carcinoma, percutaneous ablation is a potentially curative treatment. Ethanol injection is able to achieve a complete response of 70-80% and a 5-year survival of 40-60% in the treatment of hepatocellular carcinoma of 3 cm or less. Radiofrequency ablation has emerged as the more powerful alternative method. Randomized controlled trials show that radiofrequency ablation offers a higher complete response at fewer treatment sessions and better survival compared with ethanol injection. Microwave ablation has been demonstrated to be equivalent to radiofrequency ablation in both local efficacy and long-term outcome. Laser ablation is mainly applied in clinical settings in Europe. Nowadays, percutaneous ablation is commonly accepted as the best option for patients with small hepatocellular carcinoma who are not candidates for surgical resection or liver transplantation. However, whether it can compete with surgery as the first-line treatment has long been debated. There are some retrospective studies and only a few randomized controlled trials to compare the two modalities. The currently available data are not robust enough to draw a solid conclusion. This review article provides an overview of the current status of percutaneous ablation in management of small hepatocellular carcinoma and also focuses on comparison with surgical resection.

Influence of Surgical Staples on Radiofrequency Ablation Using Multitined Expandable Electrodes

PURPOSE

During radiofrequency ablation (RFA), there is a risk that the multitined expandable electrode will come into contact with one of the surgical staples used to treat local recurrence after surgical operations. Our objective was to evaluate whether a surgical staple would influence the RFA of egg white using a multitined expandable electrode.

METHODS

Multitined expandable electrodes, LeVeen needles (expandable diameter 3.0 cm), were sunk into an egg white bath with (a) no surgical staple, (b) a surgical staple touching one of the tines, or (c) a surgical staple touching two of the tines simultaneously. By connecting the LeVeen needle and copper plate at the bottom of the bath, RFA was then performed on the egg whites as a substitute for human tissue. Ten egg white baths were ablated under each of conditions (a), (b), and (c), for a total of 30 sets of coagulated egg white.

RESULTS

There was no significant difference in the time from the power-on to the roll-off (i.e., the completion and shutting off of the electric circuit) or in the maximum diameter of the thermal lesion between conditions (a) and (b) or (a) and (c). However, the minimum diameter of the thermal lesion was significantly smaller in (c) compared with (a) (p < 0.01).

CONCLUSIONS

Surgical staples have the capacity to interfere with the electromagnetic field and decrease the minimum diameter of the thermal lesion in the event that a staple touches two of the tines of a multitined expandable electrode during RFA. Although the difference might be small enough to be neglected under many clinical circumstances, we recommend that, if possible, the tines not be expanded near metallic material.

Percutaneous ablation procedures in cirrhotic patients with hepatocellular carcinoma submitted to liver transplantation: Assessment of efficacy at explant analysis and of safety for tumor recurrence

Aims of this retrospective study were to analyze the efficacy and safety of percutaneous ethanol injection (PEI) and radiofrequency ablation (RFA) in cirrhotic patients with hepatocellular carcinoma (HCC) submitted to orthotopic liver transplantation (OLT). We studied 40 patients undergoing OLT in whom 46 HCC nodules had been treated with PEI (13 nodules), RFA (30 nodules), or PEI+RFA (3 nodules). Child-Turcotte-Pugh class was A in 18 cases, B in 18, and C in 4. The mean waiting time for OLT was 9.5 months. The effectiveness of ablation techniques was evaluated by histological examination of the explanted livers. Complete necrosis was found in 19 nodules (41.3%), partial or absent necrosis in 27 nodules (58.7%). Among the 30 nodules treated by RFA, 14 were completely necrotic (46.7%) and 16 demonstrated partial necrosis (53.3%). Considering the 13 neoplasms undergoing PEI, 3 nodules showed complete necrosis (23.1%), 6 partial necrosis (46.1%), and 4 absent necrosis (30.8%). The rate of complete necrosis was 53.1% for nodules smaller than 3 cm and 14.3% for larger lesions (P = 0.033) but increased to 61.9% when considering only the lesions smaller than 3 cm treated by RFA. During the follow up, HCC recurred in 3 patients treated by PEI. No cases of HCC recurrence at the abdominal wall level were recorded. Percutaneous ablation procedures are effective treatments in cirrhotic patients with HCC submitted to OLT and are not associated to an increased risk of tumor recurrence. RFA provides complete necrosis in most nodules smaller than 3 cm, and appears to be the best treatment option in these cases.

Radiofrequency thermal ablation of liver tumors

Radiofrequency ablation (RFA) of liver tumors was first proposed in 1990. New technologies enable us to produce liver thermal lesions of approximately 3-3.5 cm in diameter; RFA has consequently become an emerging percutaneous therapeutic option both for small hepatocellular carcinoma (HCC) and for non-resectable liver metastases, mainly from colorectal cancer. New devices (for example, triplet of cooled needles, wet needles) and combined therapies (tumor ischemia and RFA) have made it possible to treat large tumors. RFA can be carried out by a percutaneous, laparoscopic or laparotomic approach. Percutaneous RFA can be performed with local anaesthesia and mild sedation; deep sedation or general anaesthesia are also used. The guidance system is generally represented by ultrasound. CT or MR examinations are the more sensitive tests for assessing therapeutic results. The series of patients treated with RFA allow the technique to be considered as effective and safe, achieving a relatively high rate of cure in properly selected cases; it should be classified as curative/effective treatment for HCC, replacing percutaneous ethanol injection. The complication rate of RFA is low but not negligible; key elements in a strategy to minimize them are identified.

Percutaneous image-guided radiofrequency ablation in the therapeutic management of hepatocellular carcinoma

Owing to surveillance programs for detection of hepatocellular carcinoma (HCC) in patients with cirrhosis, more tumors are being detected at an early, asymptomatic stage. Percutaneous ablation is considered the best treatment option for patients with Child-Pugh class A or B cirrhosis and a single, nodular-type HCC smaller than 5 cm or as many as three HCC lesions, each smaller than 3 cm, when surgical resection or liver transplantation is not suitable. Radiofrequency ablation (RFA) has emerged as the most powerful method for percutaneous treatment of early-stage HCC. Recent studies have shown that RFA can achieve more effective local tumor control than ethanol injection and with fewer treatment sessions. In a randomized trial, local recurrence-free survival rates were significantly higher in patients who received RFA than in those treated by ethanol injection, and treatment allocation was confirmed as an independent prognostic factor by multivariate analysis. Due to advances in radiofrequency technology, RFA also has been used to treat patients with more advanced tumors. Preliminary reports have shown that RFA performed after balloon catheter occlusion of the hepatic artery, transarterial embolization, or chemoembolization results in increased volumes of coagulation necrosis, thus enabling successful destruction of large HCC lesions. This report reviews the current status of percutaneous, image-guided RFA in the therapeutic management of HCC.

Thermal ablation for hepatocellular carcinoma

Thermal ablation, as a form of minimally invasive therapy for hepatocellular carcinoma (HCC), has become an important treatment modality. Because of the limitations of surgery, the techniques of thermal ablation have become standard therapies for HCC in some situations. This article reviews 4 thermal ablation techniques-radiofrequency (RF) ablation, microwave ablation, laser ablation, and cryoablation. Each of these techniques may have a role in treating HCC, and the mechanisms, equipment, patient selection, results, and complications of each are considered. Furthermore, combined therapies consisting of thermal ablation and adjuvant chemotherapy also show promise for enhancing these techniques. Important areas of research into thermal ablation remain, including improving the ability of ablation to treat larger tumors, determining the indications for each thermal ablation modality, optimizing image guidance, and obtaining good outcome data on the efficacy of these techniques.

Percutaneous ablation of hepatocellular carcinoma: state-of-the-art

Percutaneous ablation is considered the best treatment option for patients with early-stage hepatocellular carcinoma (HCC) who are not candidates for surgical resection or liver transplantation. Several methods have been developed, including intratumoral injection of ethanol or acetic acid, and thermal ablation with radiofrequency, laser, microwaves, or cryosurgery. Percutaneous ethanol injection (PEI) has been the most widely used technique. Several series have provided indirect evidence that PEI improves the natural history of HCC. Patients with Child-Pugh class A cirrhosis and either a single tumor smaller than 5 cm or as many as three lesions each smaller than 3 cm may achieve a 5-year survival of 50%. The major limitation of PEI is the high local recurrence rate, which may reach 33-43%. Radiofrequency (RF) ablation has emerged as the most powerful alternate method for percutaneous ablation. Recent studies have shown that RF ablation can achieve more effective local tumor control than PEI with fewer treatment sessions. In a randomized trial, local recurrence-free survival rates were significantly higher in patients who received RF ablation than in those treated by PEI, and treatment allocation was confirmed as an independent prognostic factor by multivariate analysis. RF ablation could therefore be considered as the percutaneous treatment of choice for patients with early-stage tumors. Further investigation is warranted to clarify whether current RF technology could offer improved results in patients with intermediate-stage HCC.