Purpose: To show treatment results and to define prognostic subgroups in patients undergoing radiotherapy for brain metastases from malignant melanoma.
Patients and methods: Between 1985 and 1993 30 patients underwent radiation therapy for brain metastases from malignant melanoma. In 9 patients they had been surgically resected. All except 1 patient received whole brain irradiation with a total dose of 20 to 46 Gy/2 to 5 weeks using daily fractions of 2.0 to 4.0 Gy. In 5 patients a local boost of 20 to 25 Gy/2 weeks was administered. Survival rates were compared using the Cox-method. Univariate and multivariate analyses were performed to define prognostic subgroups.
Results: In 6/30 patients (20%) brain metastases were diagnosed at the time of primary manifestation of melanoma. In 83% of patients brain metastases developed during the first 5 years following primary diagnosis. Late manifestation was observed (18 years). Overall survival rate of the whole group was 39% at 6 months and 23% at 1 year. Univariate analysis revealed that age at diagnosis of brain metastases, time to manifestation, number of intracranial metastases and existence of extracerebral distant metastases had significant influence on survival. Sex was not found to influence survival rate. Multivariate analysis identified the existence of extracerebral distant metastases at the time of diagnosis of brain metastases as the most important prognostic factor for survival, followed by age and surgical resection. The role of fractionation was studied separately in a subgroup of patients receiving whole brain irradiation to a total dose of 39 to 42 Gy. Survival rates deteriorated when overall treatment time exceeded 3 weeks.
Conclusion: Prognosis following brain metastases from malignant melanoma is very unfavourable. The described prognostic factors can be helpful to choose the adequate therapeutic modality for the patient, especially for selection of patients for radiosurgery. Whole brain irradiation with 13 x 3 Gy/3 weeks seems a safe and well tolerated treatment schedule either in palliative care or following surgical resection or preceding radiosurgical treatment.