[Thermoradiotherapy of malignant choroid melanoma. Development of a new microwave hyperthermia system]

The therapeutic effects of heat (43 degrees C) as an adjunct to irradiation have generated increasing interest in oncology. It was shown that hyperthermia in addition to irradiation may allow for a radiation dose reduction which may be followed by a decreased irradiation - induced ocular morbidity rate. Intraocular malignant tumors offer excellent conditions for heat application since tumor volumes are small and heat can be locally generated to the tumor through the overlying sclera. Additionally, the vascular supply of intraocular melanoma is restricted to the choroid, limiting the blood flow related heat loss. At present, both experimental and clinical thermoradiotherapy for intraocular malignancies is performed by several investigators including Astrahan (Los Angeles), Coleman (New York), Mieler (Milwaukee), Finger and Packer (Manhasset), Swift (San Francisco), Lagendijk (Utrecht), Alberti (Essen) as well as our group in Munich. Both the advantages and disadvantages of the different technical modalities including our newly designed microwave hyperthermia system are discussed and it is emphasized that thermoradiotherapy at present is almost exclusively experimental. However, it is anticipated that future technology of electromagnetic heat induction will increase the existing therapeutic potential of thermoradiotherapy in intraocular malignancies.