Hemopoietic stem cell transplantation for myelodysplastic syndrome

The term myelodysplastic syndrome (MDS) describes a spectrum of disorders t hat are characterized by dysplastic marrow cell morphology, the development of peripheral blood cytopenias, and a tendency to evolve into acute myeloi d leukemia. MDS has been recognized as a stem-cell disease, and hemopoietic stem-cell transplantation is currently the only potentially curative thera py. In patients with less advanced MDS (<5% blasts in the marrow), 3-year s urvival rates of 70% and 65% can be achieved with HLA-identical related and HLA-matched unrelated donors, respectively. The overall probability of dis ease recurrence in these patients is less than 5%. Of patients with advance d disease (5% marrow blasts or more), about 40% to 45% and 25% to 30% are s urviving in remission after transplantation from a related or an unrelated donor, respectively. This inferior outcome is largely due to a higher incid ence of post-transplantation relapse (20% to 30%), Inclusion of the Interna tional Prognostic Scoring System criteria into outcome analyses shows an in verse correlation between overall risk category and relapse-free survival a fter transplantation. future trials should explore the usefulness of differ ent transplantation regimens for different risk categories. Among patients with less advanced disease, use of a conditioning regimen that combines cyc lophosphamide and busulfan, dose adjusted to reach target plasma levels, ha s been associated with improved survival in recipients of transplants from related and unrelated donors. It has also permitted successful hemopoietic stem-cell transplantation in patients as old as 66 years of age. Improved s urvival with transplants from unrelated volunteer donors has been achieved with selection of donors based on high-resolution HLA typing. Autologous st em-cell transplantation may provide excellent consolidation for selected pa tients who have obtained complete remission with conventional chemotherapy. High treatment-related morbidity and mortality rates, particularly after a llogeneic transplantation, remain challenges that must be addressed with in novative approaches. (C) 2000 Lippincott Williams & Wilkins. Inc.