The pilot experience upon surgical ablation of large liver tumor by microwave system with tissue permittivity feedback control mechanism

Background: Microwave ablation (MWA) is used to treat patients with unresectable liver cancer. Our institutio applied a novel microwave generator capable of automatically adjusting energy levels based on feedback related t tissue permittivity. This approach is meant to facilitate ablations over larger areas and provide results of greate predictablility. This paper reports on the safety, efficacy, and feasibility of this new system in the treatment o patients with large liver tumors Methods: Between July 2012 and December 2012, a total of 23 patients with malignant liver tumors exceedin 4 cm in diameter underwent surgical MWA using a 902-928 MHz generator. The proposed system used a 14-gaug antenna without internal-cooling. Follow up on tumor recurrence was performed using contrast-enhance computed tomography or magnetic resonance imaging at 1 month and then at 3 month intervals for a perio of at least 12 months following ablation Results: Among the cancers treated, 10 were primary hepatocellular carcinomas (HCCs) and 13 were metastati lesions from primary colorectal cancer (CRLM). The mean tumor size was 5.40 cm (range of 4.0-7.0 cm). A total of 1 patients underwent MWA via open surgery, and 5 received laparoscopic MWA. The mean ablation time wa 1982 seconds, with a range of 900-3600 seconds, and the median number of ablation sessions was 2.0 (range o 1-4 sessions). The rate of complete ablation, as defined by a total loss of contrast-enhancement one mont post-Treatment, was 82.6% (19 of 23 patients), and the rate of local recurrence was 26.3% (5 of 19 patients). Fo tumors with a diameter of 4.0-7.0 cm, the technical success rate of MWA was higher for HCC patients (70%) tha for metastatic liver cancer (53.8%) patients; however, the difference was not statistically significant. All patient survived throughout the observation period, and the morbidity rate was 8.6% Conclusions: MWA treatment using the proposed system with tissue permittivity feedback control resulted in high rate of complete ablation and reduced morbidity. This approach proved to be a fast, easy, and effective optio for the ablation of large liver cancers, particularly HCCs. ? 2014 Wang et al.; licensee BioMed Central Ltd.