Interaction between microwave-induced brain hyperthermia and high dose rate radiation in the BT4 An brain glioma in rats med. app.

The cerebral BT4An glioma model in rats was used to investigate the effect of hyperthermia given in combination with radiotherapy in the treatment of brain tumours (thermoradiotherapy). Local brain hyperthermia was given at 42.4°C for 45 min by externally applied microwaves, immediately before radiotherapy (10 Gy). The aim of the study was to determine if a survival benefit can be achieved without unacceptable side-effects by adding local hyperthermia to a single dose of radiation.

• animal
• rat/BD IX (with glioblastoma-like brain tumour implantation)
• partial body: brain

In the pilot study, thermoradiotherapy increased the median life span with 20 days compared to controls, which was significantly better than that found after radiotherapy alone (7 days).
In the extended experiment the corresponding figures for thermoradiotherapy, hyperthermia alone and radiotherapy alone were 12.5, 3.5, and 3.5 days, respectively, that means that thermoradiotherapy was significantly better than radiotherapy and hyperthermia alone. Neurological side-effects were infrequent, of slight degree and reversible.
The present study demonstrates that a survival benefit of adding hyperthermia to radiotherapy can be achieved without unacceptable neurological side-effects in an animal glioma model.