Patients with locally advanced oral squamous cell carcinomas (T3-4N0-3M0) treated with RT or HT combined with RT (HRT) were analyzed retrospectively. The RT group consisted of 31 patients (M/F - 27/4), and the HRT group consisted of 32 patients (M/F - 29/3). RT was performed using conventional fractionation (2 Gy delivered 5 times/week) for a total dose of 54-60 Gy with a 2 week split course after delivery of 36-40 Gy. Regional HT was performed using a Supertherm EP40 (40.68 MHz) capacitive heating device (Moscow, Russia), for 60-70 min 3 times a week for a total of 8-10 times. Average tumor temperatures were 42.7±0.2°C. RT was performed within 10-15 min after the end of HT. Complete response (CR) of primary tumors was achieved in 20 patients (62.5%) treated with HRT, and in 11 patients treated with RT alone (35.5%) (p<0.05). There was a median time to recurrence of 36 months in the HRT group compared to 9 months in the RT group (p<0.01). At the same time, the use of HT was associated with an increased incidence of radiation-induced mucositis. Median survival time for overall survival was better for the HRT group (48.0 months vs. 26 months for the RT group) (p<0.05). In addition, employment of HT did not influence the frequency of distant metastases. From this aspect, disease-free survival was not statistically different between the two therapeutic approaches. This study demonstrates that regional HT confers a significant local control and long-term survival benefit with an acceptable toxicity risk in patients with advanced oral cancer who are receiving RT.

View full abstract

This paper describes a new heating method used to expand the heating area of a needle applicator by using a needle applicator made of a shape memory alloy (SMA) for brain tumor hyperthermia treatment. The purpose of the study described here is to show the ability of the method to expand a defined heating region. One major disadvantage of RF interstitial hyperthermia treatment is that this heating method has a small heating area. To overcome this problem, a new type of needle made of a SMA was developed. The thermal properties of this proposed method, when applied to agar phantoms, were calculated with computer simulations and these properties were checked experimentally with the current physical version of the heating system. The calculated temperatures were in close agreement with the measured temperatures with an error of 10% or less. In both the numerical calculations and experimental results the proposed SMA needle heat treatment expanded the heating area to approximately 300% of that of a non-SMA needle heat treatment. These results suggest that the proposed heating method using the SMA needle applicator is capable of being used for invasive brain tumor hyperthermia treatments.

View full abstract

A conditioning mild heat treatment can depress subsequent severe heat-induced biological damage by inducing thermal tolerance. In the work described here, the effect of a conditioning mild heat exposure at 37°C was examined on the formation of gastric mucosa damage induced by a restraint plus water-immersion stress (RWIS) treatment in mice. RWIS treatments induced stomach ulcers in about 42% of the control animals, but a mild conditioning heat treatment at 37°C was found to depress the appearance of ulcers, and only about 9% of the pre-exposed animals developed ulcers. In addition, RWIS treatment induced an apoptosis rate in the stomach of about 13%, but a conditioning mild heat treatment depressed the apoptotic rate to about 8%. Since the heat shock protein (HSP) inducer geranylgeranylacetone (GGA) also efficiently depressed stomach ulcer incidence rates, it is suggested that gastric mucosa damage may be depressed by HSPs induced by a mild conditioning heat treatment through the depression of apoptosis.

View full abstract