Myelodysplastic syndrome: Etiology, prognosis and management

The myelodysplastic syndromes (MDS) are a heterogeneous group of stem cell malignancies characterized by dysplastic and ineffective hematopoiesis and a variable risk of transformation to acute myeloid leukemia (AML). They usually occur in elderly people with an age at diagnosis of between 60 and 75 years. The natural history of these syndromes ranges from a chronic form spanning years [refractory anemia with or without ring sideroblasts (RARS)] to forms with a rapid evolution to AML [refractory anemia (RA) with excess blasts (RAEB), and refractory anemia with excess blasts in transformation (RAEB-t)]. Although the relationship between de novo AML and MDS has been controversial, recent evidence suggests that AML (especially AML in the elderly) and MDS are part of the same continuous disease spectrum rather than distinct disorders. MDS are clonal diseases with a step-wise genetic progression leading to secondary acquired, MDS specific-cytogenetic aberrations characterized by gains and loss of specific chromosomal regions. The treatment options for patients with MDS are complex and highly individualized, although, most therapies are poorly effective and the curative approaches are only available for a minority of patients.