Preleukemia is a form of early leukemia that in most cases will progress into an acute leukemia in a few months to one or two years. (Some myelodysplastic syndromes are not preleukemias.)
A significant number of people with this syndrome will have a chromosomal abnormality associated with the disease. The syndrome may be found in patients who have had chemotherapy or radiation therapy for some other malignancy. Exposure to toxic organic chemicals or radiation may also be possible causative agents associated with myelodysplasia. Perhaps because of the possible association of toxic chemicals and/or radiation, approximately half of the patients with myelodysplastic syndrome will have a detectable chromosomal abnormality in the leukemic cells .
A definitive diagnosis is generally made by evaluating a bone marrow sample. Treatment is often not urgently necessary. Some patients with preleukemia may be followed closely by their physicians without treatment for weeks or months, with blood transfusions given at two- to four-week intervals if necessary.
In almost all cases, however, the disease will eventually progress to overt leukemia, and treatment with chemotherapeutic agents should be started. The progression will be signaled by physical deterioration, an increase in the white blood cell counts, lowering of platelet counts and/or progressive anemia .
It is not yet known whether there is any significant difference in survival between people treated immediately after diagnosis and those who defer their treatment until there is a medical need.
