What are the types of MDS?

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What are the types of MDS?

Each type of MDS describes how it affects your blood cells and bone marrow and if there are any abnormal changes to your chromosomes. For example, in some types of MDS your blood will have a high number of blast cells – these are white blood cells that haven’t developed properly. In other types, your blood cells or chromosomes may be abnormal in some way.

The different types of MDS are classified into 6 subtypes under a World Health Organization (WHO) classification system: 

1. MDS with single lineage dysplasia (MDS-SLD) 
2. MDS with multilineage dysplasia (MDS-MLD)
3. MDS with ring sideroblasts (MDS-RS)
4. MDS with isolated del (5q)
5. MDS with excess blasts (MDS-EB)
6. MDS unclassifiable (MDS-U)

Understanding MDS subtypes

The name of the different MDS subtypes can sound confusing and they can be hard to understand.

• Dysplasia means the size, shape or look of blood cells is abnormal.
• Ring sideroblasts are red blood cells with ring-shaped iron deposits in them.
• MDS with deletion 5q means part of chromosome 5 is missing.

Your doctor will explain which type of MDS you have. If you are confused or have more questions, ask your doctor or specialist nurse. You can also speak to a nurse by calling our Support Line on 1800 200 700 or by visiting a Daffodil Centre.

Low-risk or high-risk MDS

Low- or high-risk MDS refers to the chance of it developing into a blood cancer called acute myeloid leukaemia (AML). The risk of this happening depends on the type of MDS you have, but most patients do not go on to develop AML.

Low risk: In this group, you have a 1 in 10 chance of developing AML. This includes the following types: MDS-SLD, MDS-MLD, MDS-RS and the 5q-syndrome.

High risk: The risk of developing leukaemia is much higher in this group. This includes MDS-EB.

The treatment of low-risk and high-risk disease is often different.

Your doctor may use the WHO classification to decide if your MDS is low risk or high risk, and also the Revised International Prognostic Scoring System (IPSS).

Revised International Prognostic Scoring System (IPSS-R)

As well as the different types of MDS, doctors may use the IPSS-R to look at how the disease is most likely to develop, based on:

• The number of cell types that are low in your blood (cytopenia)
• The amount of blasts (immature cells) in your blood and bone marrow
• Any chromosome changes (cytogenetics)

Each factor gets a score. Together, the scores tell which risk groups you fall into.                          

There are 5 risk groups:

1. Very low risk
2. Low risk
3. Intermediate risk
4. High risk
5. Very high risk

It can be confusing to understand these groups and classifications, so ask your doctor or nurse to explain more if you haven't understood. You can also ask our cancer nurses by calling 1800 200 700 or by visiting a Daffodil Centre.

Should I ask about my prognosis?

If your prognosis is better than expected, you may feel more hopeful about your illness and your future. You may feel more in control by having as much information as possible. Or you may not want to know about your prognosis. You may prefer not to think about the future too much or you may worry how you will cope if you get bad news.

• Read more on Asking about your prognosis.