[Radiotherapy of malignant melanoma of the skin]

Abstract

The malignant melanoma is presently regarded as a radiosensitive tumor. Usually the first choice treatment for primary melanomas is surgery. However, we regard operation and radiotherapy of primary melanomas of the face up to a thickness of 1 mm as equal therapeutic methods in patients who are sixty years and older. Radiotherapy can be recommended for primary melanomas of the face with higher tumor thickness or in younger patients if a major operations is too burdensome due to impaired general health or internal diseases or if the patient refuses the operation. Radiotherapy of primary melanomas of the scalp can be considered if the patient can accept the irreversible hair loss in the irradiated field. Soft x-ray therapy with single doses of 3.5-5 Gy 3-6 times weekly and total doses of 80 Gy for invasive primary melanomas and 70 Gy for in-situ melanomas has been effective. We choose a half value depth of at least 2.8 mm. The safety margin are 1 cm for in-situ melanomas, and for invasive primary tumors it should be the same as used in surgery: 1 cm for < or = 1 mm, 2 cm for 1-4 mm and 3 cm for > or = 4 mm thick lesions. Prior to soft x-ray therapy the diagnosis should be confirmed and the tumor thickness determined by a representative biopsy. If possible, nodular parts of the tumor should be totally excised. The subsequent soft x-ray therapy can then be performed with a minor half dose depth. Smaller primary melanomas may be totally excised before radiotherapy so that only the safety margin has to be irradiated. Pigment may be visible in the irradiated field up to one year after the end of radiotherapy. Melanoma metastases can be treated by radiotherapy if they grow rapidly or cause symptoms. Pain due to bone metastases is relieved or totally eliminated by this treatment. Excessively high single doses are not necessary for the radiotherapy of melanoma metastases. An adjuvant radiotherapy after excision of regional lymph node metastases does not influence the overall survival and the local recurrence rate and can therefore not be recommended.