State of the science for myelodysplastic syndrome: prognosis and promise of new therapies

Abstract

Myelodysplastic syndrome (MDS) includes a heterogeneous collection of clonal hematopoietic stem cell malignant disorders that exhibit ineffective hematopoiesis, resulting in peripheral cytopenias that include anemia, thrombocytopenia, and neutropenia. In about one-third of MDS cases, the disease will progress to acute myeloid leukemia (AML). MDS is a chronic disease associated with significant morbidity and mortality even without progression to AML; the leading causes of death are marrow failure complications such as infections and bleeding.' MDS can have a primary etiology or develop secondary to prior cytotoxic or radiation therapy. Secondary MDS has an unfavorable clinical course compared to primary MDS because it has a higher rate of progression to AML. 2 MDS is the most common hematologic malignancy in the elderly, with a median age at diagnosis of 60-75 years. The true incidence of MDS is not known; it is not routinely included in most population-based cancer registries and significant difficulties remain in the diagnosis and classification of this disease. However, it is estimated that about 15 000-20.000 new cases are diagnosed annually in the USA. Based on a limited number of regional European studies, the estimated crude incidence of MDS varies from 2.1 to 12.6 cases/100 000 per year, but it increases with age: in patients over 70 years, the rate is 15-50 cases/100 000 per year. 3 Due to prolongation of life expectancy, an increase in MDS awareness, and new treatment options, an increase in the expected incidence of MDS is expected over the next few decades.