[Radiofrequency of the liver - an update]

[Thermoablative therapy of hepatocellular carcinoma. Indications, technique and results]

Hepatocellular carcinoma (HCC) is one of the most frequent malignancies worldwide. Besides liver transplantation, which is only feasible in few patients and surgical resection, the scope of potential treatment options has considerably expanded in recent years. Thermoablative therapies are now well established in early HCC due to the low rate of complications and short hospital stay. The disadvantage of higher relapse rates compared to surgical resection will be further diminished through technical advances regarding radiofrequency ablation and microwave ablation, as well as growing experience of users and thorough multidisciplinary selection of potential candidates for thermoablative therapy.

Dual switching monopolar radiofrequency ablation using a separable clustered electrode: comparison with consecutive and switching monopolar modes in ex vivo bovine livers

Objective

To compare the in-vitro efficiency of dual-switching monopolar (DSM) radiofrequency ablation (RFA) using a separable clustered electrode (Octopus® electrodes) with consecutive monopolar (CM) and switching monopolar (SM) RFA techniques to create an ablative zone in the explanted bovine liver.

Materials and Methods

For DSM-RFA, we used a prototype, three-channel, dual generator RFA Unit and Octopus® electrodes with three, 17 gauge internally cooled electrodes. The RFA Unit allowed simultaneous radiofrequency (RF) energy delivery to two electrodes of the Octopus® electrodes as well as automatic switching among the three electrode pairs according to the impedance changes. RF energy was sequentially applied to one of the three electrodes for 24 minutes (group A; CM mode, n = 10) or alternatively applied for 12 minutes (group B; SM mode, n = 10) or concurrently applied to a pair of electrodes for 12 minutes (group C; DSM mode, n = 10) in explanted bovine livers. Changes in the impedance and current during RFA as well as the dimensions of the thermal ablative zones were compared among the three groups.

Results

The mean, delivered RF energy amounts in groups A, B, and C were 63.15 ± 8.6 kJ, 72.13 ± 5.4 kJ, and 106.08 ± 13.4 kJ, respectively (p < 0.001). The DSM mode created a significantly larger ablation volume than did the other modes, i.e., 68.1 ± 10.2 cm³ (group A), 92.0 ± 19.9 cm³ (group B), and 115.1 ± 14.0 cm³ (group C) (p < 0.001). The circularity in groups A, B, and C were 0.84 ± 0.06, 0.87 ± 0.04 and 0.90 ± 0.03, respectively (p = 0.03).

Conclusion

DSM-RFA using Octopus® electrodes can help create large ablative zones within a relatively short time.

Meta-analysis of surgical resection and radiofrequency ablation for early hepatocellular carcinoma

BACKGROUND

There is no definite agreement on the better therapy (radiofrequency ablation (RFA) versus surgical resection (SR)) for early hepatocellular carcinoma (HCC) eligible for surgical treatments. The purpose of this study is to evaluate the evidence using meta-analytical techniques.

METHODS

A literature search was undertaken until December 2011 to identify comparative studies evaluating survival rates, recurrence rates, and complications. Pooled odds ratios (OR) and 95% confidence intervals (95% CI) were calculated with either the fixed or random effect model.

RESULTS

Thirteen articles, comprising two randomized controlled trials(RCTs), were included in the review, with a total of 2,535 patients (1,233 treated with SR and 1,302 with RFA). The overall survival rates were significantly higher in patients treated with SR than RFA after1, 3, and 5 years (respectively: OR, 0.60 (95% CI, 0.42 to 0.86); OR, 0.49 (95% CI, 0.36 to 0.65); OR, 0.60 (95% CI, 0.43 to 0.84)). In the SR group, the 1, 3, and 5 years recurrence rates were significantly lower than the RFA group (respectively: OR, 1.48 (95% CI, 1.05 to 2.08); OR, 1.76 (95% CI, 1.49 to 2.08); OR, 1.68 (95% CI, 1.21 to 2.34)). However, local recurrence between two groups did not exhibit significant difference. For HCC ≤ 3 cm in diameter, SR was better than RFA at the 1, 3, and 5 years overall survival rates (respectively: OR, 0.34 (95% CI, 0.13 to 0.89); OR, 0.56 (95% CI, 0.37 to 0.84); OR, 0.44 (95% CI, 0.31 to 0.62)). This meta-analysis indicated that the complication of SR was higher than RFA (OR, 6.25 (95%CI, 3.12 to 12.52); P = 0.000).

CONCLUSION

Although local recurrence between two groups did not exhibit significant difference, SR demonstrated significantly improved survival benefits and lower complications for patients with early HCC, especially for HCC ≤ 3 cm in diameter. These findings should be interpreted carefully, owing to the lower level of evidence.