NOTE: In the WHO classification, a blast count >= 20% indicates acute leukemia.
General features:
(1) blast count in the bone marrow from 5 to 19%
(2) usually in patients > 50 years of age
(3) usually multilineage dysplasia in the bone marrow
Subtypes:
(1) RAEB-1
(2) RAEB-2
Features of RAEB-1 includes ALL of the following:
(1) 5-9% blasts in bone marrow
(2) < 5% blasts in the peripheral blood
(3) Auer rods absent
Features of RAEB-2 includes any of the following:
(1) 10-19% blasts in the bone marrow
(2) 5-9% blasts in bone marrow with 5-19% blasts in the peripheral blood
(3) presence of Auer rods
Prognosis:
• Patients usually have progressive cytopenias associated with marrow failure.
• About 25% of RAEB-1 and 33% of RAEB-2 patients progress to AML.
|
Subtype
|
Median Survival
|
|
RAEB-1
|
18 months
|
|
RAEB-2
|
10 months
|
