Preliminary assessment of low-intensity transcranial magnetic stimulation (TMS) during the treatment for brain glioblastomas.

Abstract

2545 Background: The standard treatment of malignant brain gliomas, including surgical and radiation therapies, does not provide recovery and a long-time favorable prognosis. The development of technologies and international guidelines on the introduction of electric (TTF) and electromagnetic (TMS) fields in combination treatment for glioblastomas aims to improve immediate results, as shown in experiments on human glioblastoma cell culture. The TMS protocol requires further refinement in parameters of frequency, intensity, and exposure with an assessment of the immediate results of combined treatment. Methods: The study included 60 patients diagnosed with MBG receiving osteoplastic craniotomy with radical (within visible unchanged tissues) tumor removal. Starting from the second day after the surgery, patients of group 1 (n = 30) received 10 sessions of magnetotherapy in the double exposure mode. For the first morning exposure, we used an ultra-low-frequency magnetic field (ULFMF) (0.03 to 9.0 Hz) on the hypothalamus projection area to induce a general antistress reaction. After 2.5-3 hours, local (on the surgical site) TMS exposure with the Neuro-MSD system (Russia) was applied in the pulse algorithm, up to 1 GHz and 5 Hz, 15 mT, 3 min. The induction was reduced exponentially (C = 0.8). The control group 2 (n = 30) did not receive ULFMF or TMS. Magnetic resonance imaging (MRI) was used to determine the volume of tumors (Vt, cm3) and perifocal edema (Ve, cm3) calculated according to the Shrek’s formula for an ellipsoid (V = a×b×c×π/6). Results: Before surgery, Vt = 54.7±5.7cm3 in group 1, in group 2 - Vt = 60.9±8.5cm3 (no statistical differences). After surgery and the subsequent course of ULFMF and TMS, residual tumor volumes in group 1 were 2.5 times lower than in controls (p < 0.05). The difference between Ve values before and after treatment was on average 80.7 cm3 in group 1 and 41.8 cm3 in group 2 (p < 0.05). Conclusions: The inclusion of sequential ULFMF and TMS exposures into postoperative therapy for gliomas, taking into account various vectors of the influence on the projection of centers of homeostasis regulation and the surgical field, as well as the development of programmed modes of biotropic exposure parameters, improves antitumor and anti-edematous effects.