How Are Myelodysplastic Syndromes (MDS) Diagnosed?
Diagnosing Myelodysplastic Syndromes (MDS) involves identifying abnormal blood counts and examining bone marrow cells through various tests, including:
- Blood Tests: Measures red cells, white cells, and platelets to detect abnormalities.
- Peripheral Blood Smear: Looks at the shape and appearance of blood cells under a microscope.
- Bone Marrow Biopsy and Aspiration: Collects bone marrow tissue to assess cell production and identify dysplasia (abnormal cells).
- Cytogenetic Testing (Karyotyping): Detects chromosomal abnormalities linked to MDS.
- Biomarker Testing: Identifies gene mutations that can influence prognosis and treatment.
MDS Staging and Subtypes
MDS Risk Classification (IPSS-R)
Unlike solid tumors, MDS is staged using a risk scoring system called IPSS-R (Revised International Prognostic Scoring System), which predicts disease progression based on:
- Percentage of blasts: immature cells in bone marrow
- Cytogenetic findings: chromosome changes
- Blood cell counts: hemoglobin, platelets, neutrophils
There are 5 ratings ranging from very low to very high. A lower score has a better outlook. A higher score means that the MDS is more advanced, will be harder to treat, and is more likely to turn into acute myeloid leukemia.
MDS Subtypes
According to the World Health Organization, MDS subtypes include:
- MDS with Single Lineage Dysplasia (MDS-SLD):
- MDS with Ring Sideroblasts (MDS-RS)
- MDS with Multilineage Dysplasia (MDS-MLD):
- MDS with Excess Blasts (MDS-EB-1 or EB-2)
- MDS with Isolated del(5q)
- MDS, Unclassifiable (MDS-U)
Essential MDS Testing
After diagnosis, additional tests help determine the most effective treatment approach.
MDS Testing Methods
- Flow Cytometry: Analyzes cell surface markers to confirm abnormal cell types.
- Next-Generation Sequencing (NGS): Identifies specific gene mutations (e.g., TP53, SF3B1) important for prognosis and targeted therapy.
- Iron Studies & Vitamin Levels: Rule out other causes of anemia or low blood counts.
- Bone Marrow Fibrosis Testing: Checks for scarring in the marrow.
Common MDS Biomarkers
- TP53 Mutation: Often linked to high-risk disease.
- SF3B1 Mutation: Associated with MDS-RS and better prognosis.
- TET2, ASXL1, DNMT3A, RUNX1 Mutations: May influence treatment and outcomes.
- Cytogenetic Abnormalities: del(5q), -7/7q-, +8, complex karyotypes.
