The radiotherapy of lentigo maligna and lentigo maligna melanoma of the head and neck.

Between 1958 and 1977, 8 cases of lentigo maligna (LM) and 15 cases of lentigo maligna melanoma (LMM) were treated with radiotherapy at the Princess Margaret Hospital. Only 1 of the 8 cases of LM recurred following irradiation and this recurrence was controlled with further radiotherapy. Of 15 cases of LMM, 14 were controlled by irradiation for periods ranging from two months to six years postradiotherapy; the 1 recurrence was salvaged with local excision. Conventional orthovoltage irradiation using doses of 4500--5000 rad in ten to 15 fractions has been found to be highly effective in controlling this disease. The lesion may take up to 24 months to completely regress following irradiation. The benefits of this modality of treatment for a disease process which predominantly occurs in the head and neck region of elderly people is discussed in detail. The results are compared with other methods of irradiation (Miescher's technique) and other modalities of treatment.