Hyperthermia – description of a method and a review of clinical applications

The aim of this paper is to give a concise description of hyperthermia and a brief review of its clinical applications. Hyperthermia (HT, thermal therapy) is thought to be one of the cancer therapies and is considered to be an artificial way of increasing the body tissue temperature by delivering heat obtained from external sources to destroy cancerous cells or prevent their further growth. The first principles of hyperthermic biology are presented. The phenomena of thermotolerance and radiosensitization are briefly described, as well as the concept of thermal dose delivered to the tissues. Three main clinical applications of HT are presented. They include local, regional or part-body HT and whole-body HT that deliver heat to localized, advanced or deep-seated and disseminated malignancies, respectively, depending on location, depth and staging of the tumour. Energies used to apply heat to the tumour include microwaves, radiofrequency energy, ultrasound, infrared radiators and different kinds of hot sources (hot water, ferromagnetic seeds, nanoparticles, resistive implants). General indications for each HT subtype and possible combinations of HT with other cancer treatment modalities are presented. Substantially, HT is used as an adjuvant therapy and in such a role it is being evaluated in many clinical randomized trials throughout the scientific medical centres. Their first preliminary results are already available, but still time is needed to produce firm conclusions and strict indications for hyperthermia treatment.