Analysis of dose fractionation in the palliation of metastases from malignant melanoma.

Sixty-five visceral metastases from malignant melanoma were treated with radiation therapy. A variety of total doses and dose fractions were used. Significant palliation was achieved in 40 of 65 (62%) symptomatic lesions. There was no correlation between total dose or dose fraction size and significant palliation. Brain and bone metastases were separately analyzed. Nineteen of 28 (68%) bone metastases were palliated. Appendicular bony metastases were more likely to be palliated than axial bony metastases (88% versus 60%). The palliation of bone metastases did not depend on total dose given or fraction size. Nine of 23 (39%) symptomatic brain metastases were palliated. There was no difference in the rate of palliation between solitary and multiple brain metastases. Palliation of brain lesions was not dependent on fraction size, although there was a trend to better palliation with higher total doses. These findings suggest that unlike treating cutaneous or nodal melanoma lesions for local control, there is no advantage in large fraction size when treating with palliative intent visceral melanoma lesions.