Anatomical Site-specific Modalities for Hyperthermia1

The clinical application of hyperthermia in the treatment of deep-seated tumors remains an empirical science. The pleomorphic nature of the neoplasms and the great diversity in the anatomy and physiology of the individual tumor locations make the treatment of nearly every neoplasm a unique challenge. A wide variety of devices is required, both for the administra tion of hyperthermia and for the measurement of the tempera tures achieved. At Stanford University, these include the BSD Medical Corp. annular phased array system, an isospherical ultrasound device, and interstitial radiofrequency for deep heat ing. Ultrasound transducers and a variety of microwave applica tors are used for superficial hyperthermia. Six illustrative case studies, selected from the 91 patients treated in our program since October 1981, are presented, with discussion and com parison of treatment devices. Difficulties in deep heating were encountered in several instances, believed secondary to the thickness of the s.c. fat, the relatively high heat-induced tumor blood flow, and the presence of adjacent bone. It is suggested that ultimate improvement in clinical results will be possible once a better understanding is achieved of such anatomical and physiological factors.