To evaluate the clinical efficacy and safety of conversion-controlled multi-electrode radiofrequency ablation (RFA) in the treatment of liver tumors.

Clinical data of 21 patients with liver tumors who received conversion-controlled multi-electrode RFA in the First Affiliated Hospital of Zhengzhou University from January 2016 to December 2017 were retrospectively analyzed. Among them, 17 patients were male and 4 were female, aged 31-85 years old with a median age of 56 years. The informed consents of all patients were obtained and the local ethical committee approval was received. The multi-electrode radiofrequency needle was punctured to the tumor margin according to the preoperative model with the guidance of ultrasound. RFA was performed after confirming that the tumor margin was within the ablation range of needle. the ablation effect was evaluated at postoperative 1 month by receiving ultrasound and enhanced CT/MRI examination. Postoperative complications and tumor progression were observed.

A total of 26 lesions were detected in 21 cases. At postoperative 1 month, the peripheral residuals were detected in 4 lesions. The complete ablation rate was 85%. The complete ablation rate for lesions <3 cm of diameter was 100%(5/5), and was 81%(17/21) for lesions with a diameter ≥3 cm. 2 cases developed mild skin burns, 1 case transient myoglobinuria and postoperative acute kidney injury, and 1 case obstructive jaundice, all of which were cured with symptomatic treatments. The follow-up time was 14(4-22) months. Tumor recurrence were observed in 4 cases during the follow-up period.

The conversion-controlled multi-electrode RFA system can completely include the tumors in the ablation range by constructing a needle array preoperatively, which can effectively avoid the signal interference when repeatedly placing the needle and avoid the possible needle track metastasis. It has the advantage of good ablation effect, expecially for large unresectable liver tumors.