[Hyperthermia in the treatment of cancers]

Encouraging clinical results have renewed the interest in hyperthermia for the treatment of cancer for the past few years. Several experimental studies allowed better knowing the mechanisms of action of hyperthermia at the cellular and tissular level: direct cytotoxic effect of the temperature increase, potentialization through hyperthermia of the effects of ionizing radiation and of anticancerous chemotherapeutic drugs. There are many techniques for tissue heating: local hyperthermia with external applicators (microwaves, radiofrequencies, ultrasound) or with implanted interstitial heaters; regional hyperthermia produced by ultrahigh frequency, capacitive or resistive heating systems: or generalized hyperthermia. Superficial tumors have been the subject of studies on hyperthermic therapies for many years because they are accessible and their response to treatment can be appreciated objectively. The most widely used techniques inducing hyperthermia are 434 MHz, 915 MHz and 2450 MHz microwaves. The hyperthermia is maintained between 41.5 degrees C and 42.5 degrees C in average during 45 minutes. It can be used either alone or in combination with radiation therapy or chemotherapy. The most interesting superficial tumors to be heated are those with a high potential of local recurrence or local recurrence with a low potential of remote metastasizing, for which no conventional treatment (Surgery, radiation or chemotherapy) can reasonably be contemplated: local recurrence of breast cancer as permeation nodules in the thoracic wall, cutaneous recurrence of malignant melanoma, cutaneous, subcutaneous or cervical lymphatic recurrence of malpighian cancers of the head and neck. All the results confirm the feasibility and validity of the combination of hyperthermia with radiation therapy for the treatment of superficial recurring tumors not checked by conventional techniques.(ABSTRACT TRUNCATED AT 250 WORDS)