Combining effects of epinephrine injected intratumorally and hyperthermia were studied in Lewis lung carcinoma growing in the hind legs of BDF₁ mice. When 10% of epinephrine at the amount of 0.02 ml (0.14 mg/kg) was injected intraperitoneally or intratumorally, no growth inhibition was observed. However, when the same dose of epinephrine injected intratumorally was combined with 43.5°C of hyperthermia for 45 min, the effect on tumor growth delay was three times as the effect of hyperthermia alone. The sensitizing effect depended on temperature of hyperthermia and dose of epinephrine. The effect was significantly defferent between 1% epinephrine at 43.5°C for 30-45 min or 10% epinephrine at 40.5°C for 60 min and hyperthermia alone. Number of lung metastases was also inhibited by the combined therapy with high dose of epinephrine and 43.5°C of hyperthermia. Blood flows in the tumors were inhibited depending on the dose of epinephrine. The mechanisum of sensitizing effect was considered that reduced blood flow of the tumors by locally injected epinephrine induced the changes on tumor environment, perhaps decreased pH. Intratumoral injection of epinephrine seemed to be useful for clinical hyperthermia.

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We have reported that epinephrine injected intratumorally sensitized the effect of heat depending on the temperature of hyperthermia and dose of epinephrine. In this study the effect of the administration routes and timings of epinephrine was carried out using Lewis lung carcinoma growing in the hind legs of BDF1 mice. The effects were evaluated by tumor growth delay. The strongest sensitizing effect of epinephrine was obtained by the injection immediately before heating. The sensitizing effects were observed both on intratumoral injection and subcutaneous injection around the tumors. The strong effect was observed in high concentration (20%) and small amount (0.025 ml) of epinephrine injected intratumorously for small tumors (50 mm³). And in case for large tumors (250mm³) the stronger effect was observed in medium concentration (5%) and medium amount (0.1 ml) of epinephrine injected subcutaneously around the tumors. It seemed that these effects were depended on the infiltration of epinephrine to the blood vessels nearby the tumors. The site of injection and the amount of epinephrine should be taken into consideration.

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Intracavitary hyperthermia was applied to two rectal cancers and a anal cancer in combination with radiation therapy. RF capacitive heating was performed with a cylindrical shaped electrode which was inserted through the anus and an external electrode of 20 cm in diameter. Favorable heating without pain was available and complete regression of the tumors was obtained in all cases. In the anal cancer case, histological examinations before and after the treatment revealed effectiveness of the intracavitary hyperthermia. It is considered to be a good method to actualize a selective local heating in anorectal malignancies.

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[in Japanese]

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We investigated SAR (specific absorption rate) and temperature distributions produced by two different types of hexagonal array applicators. The array applicators were composed of coaxial-slot antennas used for microwave cancer therapy. One array applicator was made of 6 antennas which were placed at apexes of a hexagon. The other array consisted of 6 antennas at apexes and one at the center of the hexagon. The side of the hexagon was chosen to be 3 cm long. The 6-antenna array driven inphase at 430 MHz had a narrow region where the normalized SAR was more than 50%. This may cause a hot spot during hyperthermia treatments. The 7-antenna array driven in-phase provided wider and more uniform heating patterns. Temperature patterns calculated from the SAR patterns agreed well with experimental ones. Finally, we proposed 'heating volume' to evaluate the heating characteristics of the hexagonal arrays.

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Interstitial hyperthermia is one of the best methods to heat only tumor without influence to the surrounding normal tissues. We used an RF interstitial hyperthermia system (MINERVE : ODAM Co. France) and treated 14 patients (42 heating sessions) of malignant recurrent tumors. All 14 cases were previously treated and refractory to the treatments. Interstitial heatings were combined with external irradiation or brachytherapy using 192-Ir thin wire. In the 13 evaluable cases, 7 cases showed complete response and 5 cases showed partial response. It was difficult to evaluate how interstitial hyperthermia contributed to this therapeutic result because of the variety of the previous treatment. But in the treatment of refractory recurrent tumors, we thought the result was satisfactory. We also analyzed acute complications especially pain and heat sense of each patients during the sessions. In 13 sessions out of 42, patients complained of pains or heat senses and in 2 sessions, intolerable pain caused interruption of the session. For the prevention of complications, 4 or more applicators should be inserted and the inserted applicators should be used only one time.

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