Acute myeloid leukemia following non-Hodgkin's lymphoma: danger of prolonged use of chlorambucil as maintenance therapy.

Four patients who developed acute myeloblastic leukemia during the treatment of a non-Hodgkin's lymphoma are described. In three cases the same sequence was observed: a favorable histological type of lymphoma, an apparently complete and lasting remission, a long period of tri-cytopenia, and finally acute myeloid leukemia. The fourth patient had a non-favourable histological type of lymphoma and developed acute myeloblastic leukemia during a relapse. The illustrations clearly show the distinction between lymphoid and myeloid disease in the four cases. A review of previously reported similar cases is summarized in two tables. Many patients received chemotherapy including alkylating agents (as did the four patients reported here). Most of them received chlorambucil, usually given over several years, at total doses ranging from 2 to 15 g. This treatment, frequently used as maintenance therapy in low-grade malignancy lymphoma, seems to be particularly dangerous.