Thermochemotherapy Using a Radiofrequency Capacitive Heating System in the Treatment of Unresectable Bile Duct and Pancreatic Cancers

Four patients with unresectable bile duct cancer and six patients with unresectable pancreatic cancer were treated by thermochemothrapy with a radiofrequency (RF) capacitive heating system, and we investigated the heating efficiency of RF heating and the antitumor effect of the treatment. Hyperthermic treatment was applied once every 1-2 weeks with an intratumor temperature of 42°C or more for 30 minutes. A strong positive correlation was observed between the maximum RF output power and the maximum temperature at the tumor center. RF output of more than 1000 W produced an effective intratumor temperature of 42°C or more. The antitumor effect of RF hyperthermia increased with increasing output of RF energy. Partial or minor responses of the tumor were observed in five patients, and improvement in performance status and reduction in serum levels of carcinoembryonic antigen or carbohydrate antigen 19-9 were observed in six patients. In three of five patients suffering abdominal pain due to pancreatic cancer, the pain was reduced. Three of the five patients in whom a tumor response was found survived more than one year; one of them has survived more than two years. In comparison with historical controls treated by conventional chemotherapy alone, the survival periods were prolonged in patients who underwent combined thermochemotherapy. Our clinical results indicate that thermochemotherapy using the RF capacitive heating system is of therapeutic benefit in the treatment of unresectable bile duct and pancreatic cancers.