MDS-EB is most common in older male adults, although it can be found in almost any population segment. MDS-EB is also commonly found in people previously diagnosed with another MDS (without blasts) or affecting single cell lines. Some MDS patients can be symptomless for years; however, MDS-EB patients frequently have symptoms related to their cytopenias, especially symptoms of anemia such as fatigue.
As stated earlier, patients with MDS-EB have a high risk of progression to acute leukemia (approximately a third of patients).
Although prognosis in other hematologic malignancies is often dependent mainly on the cytogenetic or genetic changes, it is determined differently in MDS-EB patients. One of the major prognostic indicators in this disease is the bone marrow blast count, with higher counts determining a worse prognosis; this is independent of the genetic changes. Thus, accurate counts are extremely important.
Another major indicator of poor prognosis is high peripheral blood blast counts. The survival of MDS-EB2 patients with 5-19% blasts in their peripheral blood is a forecast similar to that of Acute Myeloid Leukemia (AML). Other poor prognostic indicators are higher blast percentage in the blood than in the bone marrow and the presence of Auer rods, which is a poor prognostic indicator even with lower blast counts.
Other prognostic factors are the number and type of cytogenetic changes and the number of cytopenias.
Formerly there was a category of MDS with excess blasts in transition (the former RAEB-T), but these patients are now diagnosed as having AML.
If treatment is indicated, it depends very much on the prognostic group of the patient. The Revised International Prognostic Scoring System, or IPSS-R, is a way of taking all of the different indicators, such as the number of cytopenias present and number of blasts, etc., to determine a prognosis.
To summarize, the following are taken into account to determine the IPSS-R: the number of blasts, the karyotype, and the cytopenias, i.e., how low the hemoglobin, platelet count, and neutrophil count are).
Treatments include chemotherapy, immunotherapy, and in some cases, stem cell transplantation. Other supportive treatments include transfusions for anemia and thrombocytopenia and antibiotics for infections.
