High-powered Microwave Ablation Treatment Of Hepatocellular Carcinoma With Cooled-shaft Antenna: Experimental And Preliminary Clinical Study

Objective: This study was to evaluate the efficacy and change regulation of temperaturefield of2450MHZ microwave with high output power in ex porcine livers. Furthermore,toassess the safety and efficacy of2450MHz microwave ablation with high output in treatinghepatocellular carcinoma(HCC) and to clarify the risk factors of disease recurrence afterpercutaneous microwave coagulation therapy(PMCT).Materials and methods:(1).The2450MHZ microwave ablation and thermal monitorsystem were used in this study. Four thermocouples were placed at1.0cm、1.5cm、2.0cm、2.5cm away from the antenna to measure temperatures in real-time during microwaveemission. The high output power were60W、80W、100W and the setting time was600S.The temperatures were recorded per30seconds. The short and long-axis diametersand volumes of ablation zone were measured after every microwave emission.(2). A totalof93patients with HCC, who had not received any treatment before percutaneousmicrowave coagulation therapy(PMCT),were enrolled in this study. Written informedconsent was obtained from each patient before treatment. All the patients receievedmicrowave ablation by using high power(100W) via percutaneous approach.The procedurewas carried out for a total of106lesions with the diameter of (1.0-5.85)cm.The hepaticfunction changes, the clinical symptoms and the follow-up index for short-term therapeuticefficacy evaluation were recorded. The factors related to HCC recurrence were analysis byusing single factor analysis method.Result:(1)With the microwave output power increased, the temperatures also had atendency to increase especially in1.0cm,1.5cm,2.0cm,2.5cm points away from the antenna(p<.05).The maximum temperature with100W at10cm,1.5cm2.0cm,2.5cm fromthe antenna reached100±3.12℃、87±3.82℃、54±1.92℃respectively.Menanwhile, theMaximum short-axis diameter was3.74±0.11cm,and long-axis diameter was5.93±0.15cm,and the Maximum volume was43.41±3.43cm3respectively.The temperature of antennawas remains at25～27℃during the ablation.（2）The contrast enhanced CT or MRI was performed one month after microwave ablation.The complete ablation rate was98.11%(104/106). All the lesion were successfullypunctured by a single manipulation and the ablation procedure took2～10minutes. Afterthe microwave ablation, the patients′hepatic function was significantly different from thatdetermined befor the ablation(p<0.05). No skin burn or death occurred. Severcomplications developed in two patients, including biliary fistula(n=1) and pleuraleffusion(n=1). The one-year survival rate was94.6%（88/93）.Single factor analysis showedthat a positive correlation existed between the lesion′s number and early recurrence.Conclution:1. With high output power,2450MHZ cooled-shaft antenna can reach a highertemperature and produce a significantly large ablation in a short time. High output powerablation may be used as a fast, precise and complete ablation method for treatment of HCC.2. With an internally cooled antenna device,2450MHz MW ablation with high outputpower appears to be a safe and effective treatment with fewer complication for patients forpatients with HCC.The number of tumor lesions is an important risk factor risk factorcausing postoperative HCC recurrence.