The use of large fractions in radiotherapy for malignant melanoma

Eighty-nine cutaneous, subcutaneous or lymph node metastases of malignant melanoma in 15 patients were treated with radiotherapy using electron beams at appropriate energies (6-15 MeV). A total dose of 40 Gy was given in 8 fractions (fraction size 5 Gy) over 23 days. The therapy was given as two weekly fractions on two consecutive days with a 24-h interval. The next two fractions were given after a pause of 6 days. Eighty-six of 89 lesions (97%) responded to treatment, response rate being clearly dependent on tumour size. All the 67 lesions less than 2 cm in diameter responded, 51 of them (78%) completely disappearing, while in tumours over 4 cm among 10 lesions only 2 CR lesions were achieved. In cases where prolonged follow-up (greater than one year) was possible no major late side-effects were observed. The treatment scheme with large fractions appears to be well-tolerated and effective for metastatic malignant melanoma.