Randomised trial of hyperthermia as adjuvant to radiotherapy for recurrent or metastatic malignant melanoma

The value of hyperthermia as an adjuvant to radiotherapy in patients with malignant melanoma was studied in a European multicentre trial. 134 metastatic or recurrent lesions of malignant melanoma in 70 patients were randomly assigned to receive radiotherapy (three fractions of 8 Gy or 9 Gy in 8 days) alone or followed by hyperthermia (43°C for 60 min). Overall, the 2-year actuarial local tumour control was 37(SE 5)%. Univariate analysis showed a beneficial effect of hyperthermia (radiation alone 28% vs combined treatment 46%, P=0·008) and radiation dose (24 Gy 25% vs 27 Gy 56%, P=0·02), but no effect of tumour size (4 cm 42% vs >4 cm 29%, P=0·21). Cox multivariate regression analysis showed the most important prognostic variables to be hyperthermia (odds ratio for 2-year local control 1·73 [95% Cl 1·07-2·78], P=0·023), tumour size (0·91 [0·85-0·99], P=0·05), and radiation dose (1·17 [1·01-1·36], P=0·05). Addition of heat did not significantly increase acute or late radiation reactions. Heating was well tolerated, but because of difficulties with equipment only 14% of treatments achieved the protocol objective. The overall 5-year survival rate was 19%, but 38% of the patients for whom all known disease was controlled survived 5 years. Adjuvant hyperthermia significantly improved local tumour control when applied in association with radiation in treatment of malignant melanoma. Successful local treatment of patients with a single or a few metastatic malignant melanoma lesions has significant curative potential.