Marrow transplantation for hematologic malignancies: a brief review of current status and future prospects

The ability to transplant bone marrow makes it possible to treat patients with hematologic malignancies with doses of systemic radiotherapy or chemotherapy that would ordinarily result in fatal myelosuppression. With this approach, some otherwise incurable patients can be treated successfully. For most hematologic malignancies (acute nonlymphocytic leukemia, acute lymphocytic leukemia, chronic myelogenous leukemia, and malignant lymphoma), if transplantation is delayed until patients have end-stage disease (drug-resistant relapse) or blast crisis, approximately 10 to 20% of patients can be saved. If transplantation is carried out earlier in the course of disease, the outcome improves considerably. Some of the major limitations of marrow transplantation are the need for an appropriate source of marrow, the severe myelosuppression seen in the immediate posttransplant period, the complications of graft-v-host disease (GVHD), and disease recurrence. The use of autologous marrow and the formation of a national donor registry may make transplantation more widely applicable. The availability of growth factors can hasten hematopoietic recovery, making the immediate posttransplant period safer. New immunosuppressive regimens and T-cell depletion of donor marrow can diminish the impact of GVHD. The need for better preparative regimens persists and has emerged as the major requirement for continued progress in marrow transplantation.