[Hyperthermia of metastatic brain tumor with implant heating system: a preliminary clinical results]

Metastatic brain tumors were treated by interstitial hyperthermia with an Implant Heating System, which consists of three major parts: ferromagnetic implant (thermoseed), generator of high frequency (240 KHz) and induction coil (30 cm in diameter). The implant is made of Fe-Pt alloy, 1.8 mm in diameter and 15 to 20 mm in length, whose Curie point is 68 - 69 degrees C. Seven cases of metastatic brain tumor, 5 from lung cancer, one from breast cancer and another from colon cancer, were involved in this study. One or several implants were placed inside the tumor by CT guided stereotaxis, or manually inserted at craniotomy. Interstitial hyperthermia at 44 - 46 degrees C was made by IHS for 30 to 60 minutes twice or three times a week. External irradiation was simultaneously combined with hyperthermia in 6 cases. Repeated, longterm hyperthermia (8 - 45 times) was possible in all cases except one, whose treatment was discontinued due to migration of the implant. No other serious side effect was found in any cases during and after the treatment. Repeated CT scans reveal complete response in 2, minor response in one and progression in 3 cases. Therefore this preliminary clinical study indicates that interstitial hyperthermia with IHS is very useful and promising method for treating intracranial metastases.