A phase I/II evaluation of long-duration moderate interstitial hyperthermia and high dose rate brachytherapy in the treatment of newly diagnosed malignant gliomas

Fourteen patients with newly diagnosed malignant gliomas have been treated with conductive interstitial hyperthermia (41.5°C) combined with high dose rate (HDR) iridium-192 interstitial brachytherapy. The interstitial thermoradiotherapy was administered two weeks after external beam irradiation. Hyperthermia was administered for three hours of each four-hour period, and patients were randomized to a total heating time of 36 or 48 hours. Three HDR brachytherapy fractions were given at equally spaced intervals during the hyperthermia period, with each fraction administered during an appropriate one-hour 'no heating' time. Catheters were implanted by computed tomographic (CT) guidance in the brain. The CT scans were used to localize the tumor in three dimensions and to determine the number, location, depth of implantation, and active length of each type of catheter employed. Tumor response was determined by contrast-enhanced CT scans taken at eight to 12-week intervals. Patients were followed up for n minimum of ten months (maximum, 40 months). At the time of this analysis, six patients were-alive and eight patients had died of tumor progression. Survival for glioblastoma multiforme ranged from 36 to 122 weeks (median, 65 weeks). All patients with anaplastic astrocytoma or anaplastic oligodendroglioma are alive, with a mean survival from diagnosis of 176 weeks (range, 154 to 204 weeks). Treatment complications occurring within one month following interstitial thermoradiotherapy included mass effect requiring craniotomy for decompression (four patients), pulmonary embolus (two patients), and scalp infection (one patient). Additionally, at two months after implant, neurological deterioration was seen in seven patients with a decrease in Karnofsky Performance Status score of greater than 20 points.