Clinical trials with local (external and interstitial) irradiation and hyperthermia. Current and future perspectives.

There is a growing body of experience in the clinical use of either external or interstitial (local) hyperthermia. A great deal has been learned about the technical and prognostic factors that influence the efficacy of heat combined with irradiation. Despite some technologic advances, substantial limitations remain to the optimal delivery of heat and monitoring of the temperature throughout the treatment volume with localized techniques. Additional efforts to improve present equipment are paramount, and further studies should be encouraged to establish the optimal conditions for the delivery and temperature monitoring of local hyperthermia combined with irradiation or cytotoxic agents. It is possible to induce tumor regression and produce satisfactory palliative results in selected groups of patients with recurrent or advanced tumors. The clinical application of hyperthermia, particularly in previously irradiated patients, should be continued. Adequately designed clinical trials to amplify our understanding of this modality and its optimal clinical applications should be strongly supported.