Study on Relapsed Malignant Gliomas Treated with Electro-Hyperthermia

Aim: to evaluate the efficacy and tolerability of electro-hyperthermia (ET) for the treatment of relapsed malignant glioma.

Methods: this was a retrospective observational clinical study. Patients were included in the study if they had >18 years, informed consent signed, histological diagnosis of malignant glioma, failure of previous temozolamide-based chemotherapy and radiotherapy, indication for treatment with ET. Hyperthermia was performed with short radiofrequency waves of 13.56 MHz using a capacitive coupling technique keeping the skin surface at 26 C°. The applied power ranged between 40-150 Watts and the calculated average equivalent temperature in the tumors was above 40 C° for more than 90% of the treatment duration (20-60 minutes gradually).

Results: 24 consecutive patients were enrolled in the study, 19 (79%) had glioblastoma multiforme (GBM) 13 were of grade 1-3 and 6 of grade 4, 5 (21%) astrocitoma. Tumor response analysis two months after ET showed 2 (8%) complete remission (astrocytomas) and 5 (21%) partial remission (2 astrocitoma, and 3 glioblastomas), with a response rate of 29%. The median duration of response was 16 months (range 6-120). The median survival of whole study population was 19.5 months (range 2-156), 55% survival rate at 1 year, and 15 % at two years. We observed 3 long survivors at 156, 60, 62 months in atrocitomas.

Conclusions: ET appears to have promising efficacy in adults with relapsed malignant glioma.

Keywords: Relapsed Malignant Glioma; Electro-Hyperthermia; Survival; Tumor Response