Radiofrequency hyperthermia for clinical cancer therapy

Radiofrequency heating by the inductive or capacitive mode has the potential to induce hyperthermia at depth. Progress with the capacitive heating with the use of multiportal electrodes and impedance matching showed promise for improved depth of heating. However, heating of the fatty tissue remains a major obstacle. The inductive modality has been widely used for diathermy, and a modified unit is being used for treatment of superficial tumors. The inductive mode has great promise for heating deep-seated tumors because it is least affected by the tissue inhomogeneities. With radiofrequency heating, temperature measurements between the tumor and the adjacent normal tissue almost always showed a selective heating pattern. Tumor response to the heat alone has been transitory; however, permanent control can be achieved in over 75% when combined with irradiation without an increase in normal tissue complications.