Two possibilities are plausible as the major mechanisms of the therapeutic role of wholebody hyperthermia (WBH); one is an injury to death of tumour cells by WBH stimulation of the chronic insufficient heat dissipation and anaerobic conditions and another a potentiation of immune functions of the host. Based on a marked inhibition by a single trial of WBH of the growth of spontaneous mammary tumours in SHN mice, the above two possibilities were elucidated by this WBH system. Latency, the period between tumour transplantation and the appearance of tumour of palpable size, differed little between mammary tumours transplanted to mice receiving WBH and the same tumours transplanted to the control mice given no WBH. Meanwhile, in mice given no treatment, the latency for tumours from the donor mice which received WBH was significantly longer than that for tumours from the donor mice which given no WBH. These results revealed that the inhibition by a single trial of WBH of mammary tumour growth is ascribed to a direct effect on tumour cells rather than an indirect effect on the host.

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We have planned to start a randomized trial in which concurrent chemotherapy add to radiotherapy, concurrent hyperthermia add to radiotherapy, and combining all these three modalities for advanced cervical carcinomas.
In this preliminary study, we evaluated the clinical response and acute toxicity for three patients with FIGO Stage IIIB cervical carcinomas treated with combining all these three modalities. A complete response was achieved in 2 patients, and partial response in one patient. Grade 3 leukopenia occurred in 2 patients, Grade 2 in one patient. Grade 1 gastrointestinal and genitourinary toxicity were found in all patients. However, none of the patients had Grade 4 toxicity. Treatment with concurrent chemotherapy and hyperthermia add to definitive radiotherapy was shown to be effective in patients with FIGO Stage IIIB cervical carcinoma. In addition, a combination of all three modalities was well tolerated and had acceptable acute toxicity.

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As a step toward elucidating the cause of the anti-mammary tumour activity of far-infrared ray (FIR), effects of continuous and intermittent FIR exposure at a young and advanced age on survival rate, spontaneous motor activity, and plasma and urinary component levels were examined in ICR mice. In both sexes, chronic FIR irradiation from fetus increased the activity at a young age and showed a higher survival rate than the control until 14-17 months of age. However, the survival rate decreased thereafter associated with a marked decline of motor activity. Exposure to FIR during the light-phase only at 1-4 months of age resulted in a high survival rate throughout the experiments and prevented a decrease in the activity and an increase of body weight in both sexes. While FIR modulated the nocturnal rhythm of activity normally during both young and advanced ages in both sexes, it related little to the survival rate. The plasma and urinary component levels and oestrous cycle were influenced little by FIR. These findings indicate that the proper application of FIR can increase the life span, which would result from its maintenance of health and protection of mammary tumours and other types of diseases.

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Interstitial RF heating with an inserted electrode allows the heating position selection in a subject, but the narrow heating region is problematic. This study elucidates development of new interstitial RF heating methods, combining with external RF heating using paired electrodes, heating the subject broadly in advance in order to selectively extend the heating region. Two kinds of heating system were developed by controlling a differential mode and a common mode of RF currents. Heating experiments with a liquid adhesive subject enabled a wider effective heating region with higher initial temperatures of heating subjects by external RF heating, and larger interstitial electrode diameter.

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The responsible mechanisms for hyperthermia-induced injury in the brain are not fully understood. The changes in glucose metabolism may play an important role in hyperthermia-induced injury. To elucidate these mechanisms, the changes in local cerebral glucose utilization (LCGU) was measured following the induction of localized interstitial hyperthermia using the [¹⁴C] -2-deoxy-D-glucose autoradiographic technique. The induction of hyperthermia was achieved by using 8MHz radiofrequency (RF) in rats. The range of hyperthermia is from 37 to 45°C for 30min. We found that (1) LCGU was significantly decreased in the lesions heated to 45°C ; (2) it was increased in the lesions heated to 43°C ; and (3) it was increased in the contralateral thalamus and hippocampus of a hyperthermia group. In conclusion, severe hyperthermia at 45°C caused irreversible cell damage as shown by a marked decrease in LCGU. Hyperthermia at 43°C caused neuronal shrinkage and an increase in LCGU. In comparison with our previous cerebral blood flow (CBF) study, increased LCGU occurred prior to the oneset of decreased CBF. These findings suggest that the increased LCGU around severely damaged lesions caused by hyperthermia may be manifested as cellular injury and the threshold temperature may be 43°C for 30min.

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