Safety of Regional 8-MHz Radiofrequency Capacitive Hyperthermia Combined with Magnetic Cationic Liposomes in Patients with Castration-Resistant Prostate Cancer: A Phase I Clinical Study

Background: Magnetites (iron oxide nanoparticles in Fe3O4) coated with positively charged liposomes are called as magnetic cationic liposomes (MCLs). MCLs used in an 8-MHz radiofrequency (RF) capacitive heating device can increase the temperature of a specific site to up to 45 degrees C. The aim of this study was to evaluate the safety of regional 8-MHz RF capacitive hyperthermia combined with MCL in patients with castration-resistant prostate cancer (CRPC). Methods: Three CRPC patients resistant to standard cancer therapy were enrolled in this study. The patients were injected with 0.5 mL MCL containing Fe (30 mg/mL) into the prostate, followed by application of the heat using an 8-MHz RF capacitive heating device. The primary end point was to evaluate the presence, or absence, as well as the degree of adverse events. The secondary end point was to obtain preliminary efficacy data. Results: The temperature of the tumor was increased by more than 2 degrees C following MCL injection when compared with the 8-MHz RF treatment alone. No severe adverse events were noted in the prostate, rectum, or the bladder. After treatment, both levels of prostate-specific antigen (PSA) and interleukin-6 (IL-6) in the tissue were increased in three patients by varying degrees. Conclusion: The present study confirms the safety of regional 8-MHz RF capacitive hyperthermia combined with MCL.