Magnetohyperthermia for treatment of gliomas: experimental and clinical studies

Gliomas comprise a group of heterogeneous primary tumors of the central nervous system that originate from glial cells. Malignant gliomas account for the majority of primary malignant CNS tumors and are associated with high morbidity and mortality. Glioblastoma is the most frequent malignant glioma, and despite recent advances in diagnosis and new treatment options, its prognosis remains dismal. New opportunities for the development of effective therapies for malignant gliomas are urgently needed. Magnetohyperthermia consists of heat generation in the region of the tumor through the application of magnetic nanoparticles subjected to an alternating magnetic field and has shown positive results in both preclinical and clinical assays. The aim of this review was to assess the relevance of hyperthermia induced by magnetic nanoparticles in treating gliomas and to describe possible variations of the technique and its implication in the effectiveness of treatment. An electronic search in the literature of articles published from January 1990 to November 2009 was performed, in databases ISI Web of Science and PubMed, and after screening according to the inclusion criteria, 11 articles were selected. Animal models showed that magnetohyperthermia was effective in promoting tumor cell death and reducing tumor mass or increasing survival of the animals. One clinical study demonstrated that magnetohyperthermia could be applied safely and with few adverse effects. Some studies suggested that mechanisms of cell death, such as apoptosis, necrosis, and antitumor immune response were triggered by magnetohyperthermia. Based on these data, it was concluded that the technique proved to be effective in most experiments, and improvement of the nanocomposites, as well as of the alternating magnetic field equipment, can contribute towards establishing magnetohyperthermia as a promising tool to treat malignant gliomas.