In a series of animal tumor studies, heat was directly delivered into the tumor mass with an interstitial applicator. After hyperthermia (44°-45°C for 45 minutes) or radiation alone (3x10 Gy), only a slight delay in tumor growth was observed, while the combined treatment, either simultaneous or sequential (i.e., heat delivered four hours after irradiation), appeared to be the most effective. The cure rate in the two combined treatment groups was 100%, in contrast to the lack of cure in the first two groups. The simultaneous use of heat and x-ray appeared to be slightly more effective than the sequential schedule; in all cases, no increase in radiation effects on normal tissue could be observed. For clinical studies, 47 patients with a total of 101 neck node metastases from head and neck cancer have been treated in order to compare tumor response to at least two different combinations of treatment modalities in the same patient. All patients were irradiated according to a multiple daily fractionation (MDF) scheme (2+1.5+1.5 Gy/day, 4-hour intervals, 5 days/week), and hyperthermia (42°-43°C, 45 minutes) was delivered every other day Immediately after the second daily radiation fraction, by means of an external applicator operating at 500 MHz. With this schedule, heat is delivered simultaneously with the second and sequentially with the first and third radiation fractions. In halfthe patients, misonidazole was also administered (1.2 g/m2 up to a total dose of 12 g/m2). The data indicate that multimodality treatments seem to be more effective than conventional fractionation or MDF alone. In particular, the best response was obtained when MDF was combined with both misonidazole and hyperthermia. No increased radiation reactions have ever been observed in patients treated with hyperthermia also; all side effects depend mainly on misonidazole toxicity.
Arcangeli, G. and Cividalli, A.
"Local Hyperthermia and Radiation: A biologically-oriented clinical scheduling,"
Henry Ford Hospital Medical Journal
: Vol. 29
Available at: https://scholarlycommons.henryford.com/hfhmedjournal/vol29/iss1/8