Melphalan-related leukemia in multiple myeloma.

Five patients with multiple myeloma ending in acute leukemia are described. The preleukemic phase was characterized by anemia, leukopenia and/or thrombocytopenia. The incidence of acute leukemia in myeloma was calculated to be 6%. Melphalan therapy for more than two years increased the incidence to 14%. All patients who developed leukemia had received a total melphalan dose of at least 1 100 mg.