Lyso-thermosensitive liposomal doxorubicin (ThermoDox®) is a temperature sensitive liposomal drug delivery system that selectively accumulates in tumors as a result of their leaky vasculature. During ThermoDox/hyperthermia therapy, the tumor is heated locally while the rest of the body remains at a normal temperature. When the liposomes encounter a temperature of 39.5°C or above, they release doxorubicin locally into the heated area. Liposomal doxorubicin is administered intravenously and, because it is particulate, will eventually be removed from circulation by the reticuloendothelial system in the liver and spleen. Pharmacokinetic data from liver cancer patients treated with radiofrequency ablation (RFA) and ThermoDox show that the major portion of exposure to ThermoDox (about 95% of the liposomal doxorubicin plasma AUC0-∞) occurs during the first six hours following the infusion, establishing this time period as optimal for application of hyperthermia. Animal studies have repeatedly shown higher tumor doxorubicin concentrations and enhanced tumor cell killing when ThermoDox is combined with hyperthermia compared to doxorubicin without hyperthermia.