Management of high-risk myelodysplastic syndromes

Cytogenetic aspects of adult primary myelodysplastic syndromes: Clinical implications

Myelodysplastic syndrome (MDS) is a heterogeneous disease from the clinical, biological and morphological point of view. The pathogenesis of MDS is not well established and it appears to occur complex changes in the stem cell biology. Clonal chromosomal aberrations are found in 30-50% of primary MDS and no specific cytogenetic abnormality has as yet been defined. The chromosomal abnormalities are predominantly characterized by partial/total chromosomal losses or chromosomal gains. These chromosomal abnormalities include mainly -5/del(5q), -7/del(7q), del(11q), del(12p), del(20q), -Y, and +8. The role of cytogenetic analysis in the diagnosis, prognosis, taking treatment decisions and follow up of patients with MDS has been clearly defined. Despite its difficulties in obtaining for analysis high quality metaphases conventional cytogenetics continues to be the basic technique for cytogenetic evaluation of a MDS patient. Other molecular cytogenetic methods have been shown to be complementary, without replacing the information obtained with this technique. Further investigations with both conventional and molecular cytogenetics in relation to clinical features as well as other molecular methods will undoubtedly contribute to improve understanding of the underlying genetic events responsible for the development and evolution of MDS leading to more accurate classification and management of MDS patients.

Normal bone marrow function over 6 years in a patient with dysplastic hematopoiesis and a complex karyotype

Myelodysplasia associated with a complex karyotype is usually associated with advanced stage myelodysplastic syndrome (MDS) and an enhanced risk to develop secondary leukemia. We report on a 36-year-old female patient who was first presented in 1997 because of 'Pseudo Pelger-Huet' neutrophils. The remaining blood and differential counts were normal. Bone marrow examination revealed dysplasia in the erythroid and granulocytic series, no increase in blasts, and a karyotype with complex aberrations involving chromosomes 7, 13, 20 and 22. Almost all metaphases examined appeared to be affected. During the next few months, the patient was closely monitored and considered as candidate for bone marrow transplantation. However, blood counts remained stable without occurrence of significant cytopenias or an increase in blasts. Re-examinations of the bone marrow in 1998 and 1999 disclosed identical results compared to that obtained in 1997. After a total follow up of 6 years, the patient is still in good health with normal blood counts and persisting 'Pseudo Pelger-Huet' neutrophils. This exceptional case supports the notion that complex chromosomes are not invariably associated with rapid disease evolution in MDS.

Pathogenesis, classification, and treatment of myelodysplastic syndromes (MDS)

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal myeloid disorders characterized by morphologic dysplasia in one or more cell lineages. Dysplasia in MDS is associated with insufficient production of blood cells and consecutive cytopenia(s). The natural course and prognosis of MDS vary among patients and depend on genetic defects that occur during clonal evolution. In a significant group of patients (roughly 30%) progression to secondary leukemia is observed. These patients appear to have a grave prognosis. The treatment of patients with MDS has to be adjusted to the individual situation and age in each case. In many patients, control of blast cell production by palliative cytoreduction, continuous support with red blood cells, as well as other supportive measures, seem appropriate. In other patients, however, curative therapy (chemotherapy, stem cell transplantation) should be considered. The final decision to offer curative therapy must be based on many different factors including age and the overall situation of the patient. Recently established scoring systems aimed at predicting survival and evolution of leukemia in MDS may be helpful in this regard.