The present invention relates to a portable radiofrequency (RF) hyperthermia device having flexible applicator treatment electrodes for electric field capacitive coupled energy transfer, the device being useful for increasing the delivery of a systemically delivered drug at a localised target site. The portable RF device is suitable for use by a patient in their own home and the flexible applicator is a flexible, porous, light and easy to manipulate treatment electrode. The inventive device requires no specialist operator to ensure correct usage.