Outcome of Cancer Clinical Researches Using Heat-Generating Nanoparticles and Novel Concept of its Therapeutic Use

Cancer clinical researches using heat-generating nanoparticles have been conducted in four Japanese universities including authorsʼ universities. The nanoparticles were injected intratumorally and its heat generation was induced by external magnetic field irradiation to kill cancer cells. Three kinds of composite magnetites nanoparticles were applied to clinical researches in combination with either types of magnetic field irradiators generating different frequencies. In this paper we reviewed results of these researches with our unpublished data and discussed its potential and further refinement. Critical issues of clinical feasibility were not found in key process of treatment such as nanoparticles injection, magnetites imaging and magnetic field irradiation. A combinational use of magnetite cationic liposomes (MCL) and alternating magnetic field (AMF) irradiator was found to exhibit tumor regression activity without adverse events such as skin burn and histological damages of surrounding normal tissues. However, efficacies were found variable among tumors whose temperature rise was commonly achieved. In order to ensure efficacy, we discussed importance of MCL dosage divided by tumor volume (mg/cm3) and proposed total heat dose divided by tumor volume (J/cm3) as candidate index to control clinical treatments.