As mentioned previously, MDS is classified into low, intermediate, and high risk grades. The three risk grades are based on the duration of survival and the incidence of evolution to acute myeloid leukemia (AML).
Low risk: MDS with single lineage dysplasia (with or without ring sideroblasts) and MDS with 5(q) deletion chromosome
- Bone marrow blasts <5%
- Blood blasts: <1%
Intermediate risk: MDS with multilineage dysplasia (with or without ring sideroblasts)
- Bone marrow blasts <5%
- Blood blasts: <1%
High risk: MDS with excess blasts:
- MDS-EB1: bone marrow blasts 5%-9% , Blood blasts 2-4%
- MDS-EB2: bone marrow blasts 10%-19%, blood blasts 5-19%
The cytogenetic karyotyping plays a vital role in the risk stratification as well:
Good risk category: patients with normal cytogenetic, or 5(q) deletion, or 20(q) deletion chromosome
Poor risk category: patients with deletion of chromosome 7, or complex genetic abnormalities
