Radiation therapy of intracranial malignant melanoma

Sixty-four consecutive patients with intracranial malignant melanoma were irradiated between January 1980-March 1994. The long-term results of the irradiation were analyzed. Four patients with intended radiation therapy interrupted were excluded from the survival analysis. The remaining sixty were divided into groups using the total dose of 40 Gy and normalized total dose at 3 Gy (NTD3Gy) with 30 Gy as cutpoints. These subgroups did not differ markedly as to sex, age, KPS, single vs. multiple metastases, extracranial disease; surgical intervention on brain, prior chemo and/or immunotherapy. Those with higher total doses to the tumour area had significantly better (P = 0.0006) survival. The median survival of the whole group was 4.1 months and those with NTD3Gy > 30 Gy survived the median time of 9.6 months, whereas those with NTD3Gy less than or equal to 30 Gy had a median survival of 2.1 months. The survival difference existed also after the exclusion of those with previous craniotomy (median survival 11.9 months) and was 1.9 vs. 8.3 months when NTD3Gy > 30 Gy was the cutpoint between the groups. In a multivariate analysis, the NTD3Gy turned out to be the most significant prognostic factor (P < 0.0001). The results reveal that the total dose of radiotherapy in the treatment of cerebral metastases of malignant melanoma might have a greater impact on patients' prognosis than previously considered.