Role of radiotherapy and hyperthermia in the management of malignant melanoma.

The overall response rates of malignant melanoma (MM) to ionizing radiation are similar to those of other malignant neoplasms. This is based on recent radiobiological data on MM cell lines and radiobiological analyses of large clinical experiences, using a spectrum of fractionation schedules on diverse MM lesions. In contrast to other carcinomas, MM exhibits an unusual spectrum of radiobiological responses characteristic for early- and late-response tissues implying that there is a wide range of sensitivities to radiation fraction sizes. This is confirmed by clinical response and tumor control data from prospective trials in which different fractionation schedules produced control rates between 40 and > 90%. These experiences suggest that primary MM lesions as well as skin and lymph node metastases may be more responsive to larger fraction sizes than parenchymal metastases. The same holds true when irradiation is used as an adjuvant for locoregional treatment of the primary MM and draining lymphatics. Total doses for maximum tumor control rates remain to be established for the different fractionation schemes of proven effectiveness. Hyperthermia in combination with regionally applied cytotoxic agents or irradiation has produced encouraging enhancements in MM cytotoxicity. However, due to contradicting results, these data need to be validated by additional clinical investigation.