Treatment of hepatocellular carcinoma using internally cooled electrodes. A prospective comparison of modified automated vs. manual pulsed radiofrequency algorithms.

Objectives: To compare the effectiveness of modified automated and manual pulsed radiofrequency (RF) algorithms using internally cooled electrodes for hepatocellular carcinoma (HCC).

Methods: Seventy-seven treatment-naive cirrhotic patients with 102 HCC (< or =4 cm) underwent 109 sessions of ultrasound-guided percutaneous RF ablation using a 17-gauge, 20-cm-long, single internally cooled electrode. Patients were assigned alternatively: 40 patients to the modified automated algorithm group and 37 patients to the manual algorithm group. The mean tumor diameters were 2.34 +/- 0.9 and 2.25 +/- 0.7 cm in the automated and manual groups, respectively (p = 0.56). Primary technique effectiveness and local tumor progression were compared between the two groups.

Results: More overlapping ablations (n = 112) were required in the manual than in the automated group (n = 82) to achieve similar primary technique effectiveness rates of 96.1 and 94.1%, respectively. After a mean follow-up period of 26.7 +/- 1.1 months, the local tumor progression rates at 12 and 18 months were 4 and 20% in the manual group and 12 and 24% in the modified automated group (p = 0.3). Only tumors >3 cm were independently associated with local tumor progression (odds ratio 1.25; 95% CI 1.06-2.34, p = 0.03).

Conclusions: The manual algorithm requires more overlapping ablations and treatment sessions in order to achieve similar primary technique effectiveness and local tumor progression rates compared with the modified automated algorithm.