What is myelodysplasia (MDS)?

Myelodysplasia is also called myelodysplastic syndrome (MDS). MDS is a type of blood cancer that affects the bone marrow.

In MDS, the bone marrow makes abnormal blood cells. These abnormal cells are called dysplastic cells. Dysplastic cells do not work and are quickly destroyed by the body. This means there are not enough blood cells in the blood.

Sometimes MDS can develop into acute myeloid leukaemia.

There are different types of MDS. Some types develop slowly. Others develop quickly and have a greater risk of changing into leukaemia.

MDS is more common in people aged over 70, but it can happen at any age.

To understand MDS and its treatment, it can help to know more about the blood and bone marrow.

Types of MDS

There are different types of MDS. These are based on:

  • which type of blood cell has become abnormal – for example, red blood cells, white blood cells or platelets
  • how many immature blood cells (blasts) are in the blood
  • whether there is a genetic change in the blood cells – the main one is called isolated del (5q), but there are others.

Genes carry the instructions that cells in the body need to work properly. There are genes that control how many blood cells are made in the bone marrow.

Genes can develop changes over time. Genetic changes do not always cause problems, but they can cause conditions such as MDS.

The names for different types of MDS are complicated. Your haematologist or clinical nurse specialist can explain the type of MDS you have and what this means.

Types of MDS include the following:

  • MDS with single lineage dysplasia (MDS-SLD)

    1 type of blood cell has become abnormal.

  • MDS with multilineage dysplasia (MDS-MLD)

    2 or more types of blood cell have become abnormal.

  • MDS with ring sideroblasts (MDS-RS)

    Some of the cells in the bone marrow have small specks of iron inside them. These cells are called ring sideroblasts.

  • MDS with excess blasts (MDS-EB)

    The number of blast cells in the blood and bone marrow is higher than normal.

  • MDS associated with isolated del (5q)

    The cells in the bone marrow have a genetic change called isolated del (5q).

  • MDS unclassified (MDS-U)

    This includes any type of MDS that does not fit into any of the above categories. If you have one of these, your haematology team can explain more about it.

MDS can also be described as primary or secondary.

  • Primary MDS

    In most cases, the cause of MDS is unknown. This is called primary MDS.

  • Secondary or therapy-related MDS (t-MDS)

    A small number of people develop MDS after treatment with chemotherapy or radiotherapy. This is called secondary or therapy-related MDS (t-MDS).

Related pages

Symptoms of myelodysplasia (MDS)

Some people are diagnosed with MDS after a blood test for another reason and before they have any symptoms or complications caused by MDS.

Symptoms and complications of MDS are caused by low levels of healthy blood cells. Symptoms can include:

  • feeling weak, tired and breathless because of a lack of red blood cells (anaemia)
  • having a higher risk of infection because of a low number of white blood cells
  • abnormal bruising or bleeding because of a low number of platelets.
Related pages

Diagnosis of myelodysplasia (MDS)

If your doctor thinks you may have MDS, they will refer to you to the hospital to see a specialist blood doctor called a haematologist.

At your hospital appointment, you may also meet a clinical nurse specialist. They may be your key worker. This means they are your main contact for information and support.

Your haematologist will decide whether you need further tests. This can include more blood tests and a bone marrow biopsy.

  • Full blood count (FBC)

    This blood test counts the numbers of red blood cells, white blood cells and platelets in your blood.

  • Bone marrow samples

    Your doctor may want to take a sample of bone marrow to look at under a microscope. This is called a bone marrow biopsy. Doctors usually remove the sample from the back of the hip bone (pelvis).

    The sample is sent to a laboratory to be checked for abnormal cells.

  • Genetic tests on bone marrow cells

    A doctor examines the chromosomes inside the bone marrow cells that are taken during your bone marrow biopsy. This is called cytogenetic testing.

    Chromosomes are groups of genes. Genes carry the instructions for cells and control how they work and behave. Genetic changes can help predict how the MDS might behave over time.

Waiting for test results can be a difficult time. It may help to talk to your family, friends or clinical nurse specialist.

Risk groups for myelodysplasia (MDS)

MDS is divided into different risk groups. These can describe:

  • how quickly or slowly MDS may develop
  • the risk of it developing into leukaemia.

Knowing your risk group can help you and your doctor think about the best treatment options for you.

The MDS risk groups are based on:

  • blood cell count
  • how many immature blood cells (blasts) there are in the bone marrow
  • the results of cytogenetic tests.

Doctors often use a system called the revised International Prognostic Scoring System (IPSS-R). It divides MDS into 5 risk groups:

  • very low risk
  • low risk
  • intermediate risk
  • high risk
  • very high risk.

Your haematologist may use other definitions of risk groups to describe the MDS.

Treatment for myelodysplasia (MDS)

Before treatment, a team of health professionals work together to plan the treatment they feel is best for you. This team is called a multi-disciplinary team (MDT).

The MDT look at your:

  • test results
  • risk group
  • general health.

Your doctor will talk with you about treatment options. Treatments may be used to help with symptoms or reduce the risk of complications of MDS. This is called supportive treatment.

Treatment can also be used to help control MDS. Less commonly, the aim of treatment may be to try to cure MDS. You may be offered treatment as part of a clinical trial.

The best treatment for you will depend on:

  • the risk group you are in
  • the type of MDS you have
  • your general health
  • your own preferences and what is important to you.

If you have very low-risk, low-risk or intermediate-risk MDS without symptoms, you may not need treatment straight away. Instead, you have regular check-ups and your blood count is monitored. This is sometimes called active monitoring or watch and wait.

You and your doctors will talk about your treatment options and the possible risks and benefits before you agree (consent) to have treatment.

Supportive treatment

  Supportive treatment aims to help treat symptoms and reduce the risk of complications caused by MDS.
  • Transfusions

    You may feel weak, tired or breathless. This is caused by low levels of red blood cells (anaemia). Or you may have abnormal bruising and bleeding caused by a low platelet count. You can have blood transfusions or platelet transfusions to help improve these symptoms.

  • Reducing your risk of infection

    If your white blood cell count is low, you are at increased risk of infection. Your clinical nurse specialist or haematologist will give you advice about avoiding infection

  • Growth factors

    Growth factors may help to increase the number of healthy red and white blood cells in your blood. Growth factors are made naturally by the body. But they can be made as a drug to stimulate the bone marrow to make more blood cells:

    • Erythropoietin (EPO) stimulates the bone marrow to make more red blood cells. It can help treat the symptoms of anaemia and reduce the number of blood transfusions you need.
    • G-CSF stimulates the bone marrow to make more white blood cells. This can help prevent infection.

    Both of these treatments are given as injections under the skin (subcutaneously). A nurse can sometimes teach you how to give them yourself.

Treatment to control MDS

Different treatments can be used to help control MDS.

  • Chemotherapy

    Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. It can be given to help control MDS. The aim is to get the bone marrow working better.

    The type of chemotherapy you have depends on your general health, your risk group and how MDS affects you.

    Chemotherapy can be given as an outpatient or during a short stay in hospital. You usually have chemotherapy as an injection into a vein (intravenously). It is sometimes given as an injection under the skin. You may have a single drug. Or you may have 2 or more drugs together – this is called combination chemotherapy.

    Azacitidine is a chemotherapy drug for people with higher-risk MDS who are not able to have, or do not want, more intensive treatment. Azacitidine is given as an injection under the skin. Side effects include problems such as pain or redness at the injection site, feeling sick and feeling tired. It can also reduce your blood cell count for a short time. This can cause an increased risk of infection, anaemia and abnormal bruising or bleeding.

  • Intensive chemotherapy

    High doses of chemotherapy may be offered to people with higher-risk MDS. This treatment is also used to treat acute leukaemia. You need to stay in hospital for several weeks to have this.

    If this treatment works well, you may be able to have a donor stem cell transplant afterwards.

  • Donor stem cell transplant (allogeneic transplant)

    A small number of people with higher-risk MDS may be able to have a donor stem cell transplant. This treatment replaces bone marrow that is no longer working properly with healthy stem cells from another person (donor). These new stem cells make healthy red and white blood cells and platelets.

    This treatment can sometimes cure MDS. But it can also cause serious side effects, so it is not suitable for most people. Your general health needs to be good. Your haematologist will talk to you about the risks and benefits of donor stem cell treatment if this is a possibility for you.

  • Lenalidomide

    If you have MDS associated with isolated del (5q), you may have a drug called lenalidomide (Revlimid®). Lenalidomide comes as capsules. You usually take it for 21 days and then have a break for 7 days. Then you repeat that cycle. Lenalidomide works in several different ways to target abnormal blood cells. It is a type of targeted therapy and a type of immunotherapy.

  • Immunosuppressants

    Drugs that suppress the immune system can sometimes improve the blood count in people with MDS. They include anti-thymocyte globulins (ATGs) and ciclosporin.

  • Clinical trials

    Doctors are always researching new treatments for MDS or new ways of giving existing treatments. Your haematologist or clinical nurse specialist might talk to you about taking part in a clinical trial if this is suitable for you.

Pregnancy, fertility and myelodysplasia (MDS)

If you are planning to get pregnant or to make someone pregnant in the next few months, talk to your doctor first.

Chemotherapy and some other treatments may affect the development of an unborn baby. Doctors usually advise against getting pregnant or making someone pregnant during these treatments and for a few months after. It is important to use effective contraception.

Chemotherapy may affect fertility. If this is a concern for you, talk to your doctor before starting treatment.

If you are planning to get pregnant, MDS can increase the risk of complications during pregnancy. But with risk-reducing treatments and careful monitoring during pregnancy, most babies are born healthy. Your haematologist and obstetrician (doctor who specialises in pregnancy) will work together to give you the best care during your pregnancy.

Living with myelodysplasia (MDS)

If you have MDS, you need regular check-ups and blood tests. If you are worried or notice any new symptoms between appointments, tell your haematologist or clinical nurse specialist as soon as possible.

Making lifestyle changes to reduce your risk of complications can sometimes be challenging. You may find it easier to make changes as part of a group or with help from others. If you find it hard to make changes, tell your GP, practice nurse or haematology team. There is lots of support available to help you live a healthier lifestyle.

Your feelings

Everyone has their own way of dealing with the different feelings they experience. You may find it helpful to talk about things with family members, friends or your specialist doctor or nurse. 

Macmillan is also here to support you. If you would like to talk, you can:

The organisations below also offer information and support:

  • Leukaemia Care

    Leukaemia Care is a national blood cancer support charity for people with leukaemia and other blood disorders. It has regional support groups.

  • MDS UK Patient Support Group

    MDS UK Patient Support Group is for anyone affected by myelodysplastic syndromes.

  • Blood Cancer UK 

    Blood Cancer UK is a blood cancer research charity that provides information and support on any type of blood cancer.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Anne Parker, Consultant Haematologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 March 2023
Next review: 01 March 2026
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.