Acquired Myelodysplasia or Myelodysplastic Syndrome: Clearing the Fog

Figure 1

Age-related incidence of MDS and frequency estimates of MDS subsets. (1) De novo MDS (primary): estimates are 85% of all MDS. About 45–50% manifest cytogenetic abnormalities evident by standard analysis with recurring examples being del (5q), del (7q), del (20q), and trisomy 8. (2) Secondary MDS: estimates are 7–12% of all MDS with >80% relating to prior therapy with mutagenic chemicals and/or radiation (therapy-related, t-MDS). Chromosome aberrations are present in >90%, particularly involving chromosomes 5 and 7, and often associated with complex cytogenetics and poor prognosis. (3) Cigarette smoking is strongly associated with MDS/AML and directly relates with the total amount smoked and current smoking at diagnosis. (4) Subsets of MDS characterized by ringed sideroblasts may have different causation from other MDS syndromes. (5) Perhaps 5–10% of individuals with MDS as defined only by morphologic aberrations and cytopenias and with clinical features suggesting autoimmune disease may respond favorably to immunosuppressive therapy. (6) Occupational/environmental chemical exposures are thought to cause <1% of all MDS with benzene-related disease some fraction of this amount.