Use of radiofrequency electromagnetic fields applied by capacitive hyperthermia for glioblastoma therapy

Radiofrequency electromagnetic fields applied by capacitive hyperthermia (cRF-HT) might be applicable to improve therapy for glioblastoma patients, but computer simulation data is scarce. We aimed to perform a numerical analysis of cRF-HT treatment in glioblastoma patients.

The EHY-2030 cRF-HT system (Oncotherm, Budapest, Hungary) was studied using a round 20 cm diameter electrode. Realistic head models and quasi-electrostatic finite element simulations were created (Sim4Life v7.2, ZurichMedTech, Zürich, Switzerland). First, 109 spherical glioblastoma localizations were created within a healthy head model, and three different electrode setups were used to simulate the specific absorption rate (SAR). Then, in 20 real glioblastoma patients, the E-field and SAR in the gross tumor volume (GTV) and its boundary zone were simulated, and transient temperature simulations were performed.

The simulations conducted on 20 patients revealed that the SAR achieved in the GTV and its surrounding boundary zone is highly dependent on the localization of the tumor, with a mean SAR of 24.3 W/kg (ranging from 11.5 to 46.7 W/kg). The mean temperature within the GTV was higher in patients with a resection cavity (mean T₅₀: 40.1 °C) instead of a macroscopic tumor (mean T₅₀: 37.8 °C). The simulation outcome for the 109 artificial tumor localizations indicated enhanced effectiveness when the electrode is setup as close to the GTV as possible.

cRF-HT may induce mild hyperthermia in a subgroup of glioblastoma patients with resection cavities. In macroscopic tumors, temperatures remain below the hyperthermia threshold. Further research is required to assess the clinical benefit of this therapy.