Japanese experience in the treatment of myelodysplastic syndromes

In spite of the numerous therapeutic attempts cited, the overall results have been unsatisfactory, because responses are usually modest, short in duration, and often associated with considerable toxicity. No treatment has proven superior to conventional supportive care. A marked heterogeneity exists in the clinical manifestations and outcome of MDS on the whole, and even within single subtypes of MDS. The heterogeneity should be taken into account in the selection of therapeutic options. Leukemic transformation and nonleukemic death, notably infections and bleeding, are the two major determinants of prognosis. The risk factors for the two clinical settings are, at least in part, separable. In addition, some patients can survive for more than 5 years. Analysis of the clinical conditions of these long-term survivors suggests that, in a small number of patients, the chance of long-term survival is more likely to be a part of the natural history rather than the result of treatment. Thus, careful evaluation of the initial data is essential in designing treatment for MDS patients so that risks and benefits can be weighed against the possibility of long-term survival. Recombinant hematopoietic growth factors may provide some hope. These biologic factors have considerable advantages over many pharmaceuticals in that they are natural, short-lived, less toxic, and highly effective. In fact, the overall efficacy of CSFs has been outstanding for disorders hitherto viewed as otherwise refractory. Maintenance treatment utilizing these factors in a carefully designed prospective study is urgently needed to determine whether such a treatment modality may lead to alteration of the natural history and prolongation of survival. Finally, combined use of these growth factors is another area warranting further investigations to achieve sustained improvement in either two- or three-cell lineages.