HYPERTHERMIA

	The therapeutic effects of Hyperthermia on the human body have been well- known since the 19th Century, mainly being indicated for inflammatory processes, usually accompanied by pain, and generally applied in oncology. Methods used made it very difficult to obtain deep, controlled and harmless thermal increase and some required "invasive" techniques. Since 1985 over 500,000 people world-wide have benefited from this method. Envita uses a "non-invasive" Hyperthermia method that provides all the advantages of a deep thermal increase- even in cerebral tissue - with none of the drawbacks of systems known up to that time. HYPERTHERMIA METHODS Systems used to produce Hyperthermia dating back over a century were extremely varied. Attempts were made to increase the temperature at a deeper level using external heat sources (conduction), thus generating the serious risk of skin burns.
	Capacitive Electric Transfer (CET) is a method that allows the RF electrical current to be transferred "by capacity" (principle of the electrical capacitor) to the patient's body via a moveable external application electrode. This is covered with an insulating film which acts as dielectric and the body acts as a second plate of the capacitor. A return plate closes the circuit. The electric circulation through the resistive medium formed by the live tissues increases its temperature. The Resistive Electrical Transfer (RET), introduced in 1994, is different from the CET in that basically the application electrode is not insulated, allowing the current to be transferred directly to the patient with less dispersion, thus obtaining an increase in temperature at a greater depth. BIOLOGICAL EFFECTS Increase of arterial circulation - vasodilatation -, giving rise to increased oxygenation and a decreased acidity of the tissues. Increase of venous drainage with greater re-absorption of catabolites and decreasing of the oedema in areas with inflammatory processes. Increase of the permeability of the cellular membrane, allowing better transfer of metabolites through it. Speeding up of cicatrization of wounds. Stimulation of the immune system and decrease of free radicals. HYPERTHERMIA APPLICATIONS Hyperthemia is currently being applied in most medical specialities, particularly in: Traumatology and Rehabilitation. Rheumatology. Sports Medicine Neurosurgery and Neurology. Dermatology. Pain Clinics. Oncology : Radiotherapy and Chemotherapy ONCOLOGY ACTION OF HYPERTHERMIA 1. Greater heat sensitivity of neoplastic tissues to hyperthermia due to its chronic ischemia and hypoxia and acid pH. 2. Lethal effect on tumoral cells at a temperature of 43ºC., depending on the application time. The application of repeated moderate hyperthermia at between 39 - 41 ºC can also produce a temporary growth stabilisation. 3. Prolongated action of the temperature inside the tumour - due to lower thermal dissipation caused by a chronic ischemia, as a result of its reduced vaso-regulation mechanisms -, that increases to an even greater degree of its ischemia, hypoxia and acidity typical of tumour tissue. 4. Alterations in the cycle of the neoplastic cells, which lead to the blocking of the mitosis in part of the cell population. The blocking seems to be due to a disruption in the synthesis phase of DNA (S-phase of the cell cycle). 5. Hyperthermia has a more marked action on the central core of tumour -necrotic, ischemic, hypoxic and with low pH-, which is less sensitive to radiation. In the tumour periphery -vascularized and with greater cell growth-, radiotherapy is more effective. The benefits of a combined action of Hyperthermia and RT and/or ChT were demonstrated many years ago. 6. It can facilitate apoptosis mechanisms, self -destruction of cells, which are normally absent in tumoral cells. 7. The "athermic" effect on cell cultures has shown a significant decrease of the neoplastic cell population and no undesirable effects on normal cells. This could be related to changes of the electrical potential of the neoplastic tissues. HYPERTHERMIA ENHANCES RESULTS OF OTHER CANCER TREATMENTS A large body of medical evidence shows that when hyperthermia is used in combination with radiation therapy or chemotherapy there is a dramatic improvement in response rates. A recent study comparing results from leading hyperthermia researchers showed that beneficial responses were obtained by only 33% of patients treated with radiation alone, compared to 67% when radiation therapy was combined with hyperthermia.