Myelodysplastic syndromes (MDS)

Myelodysplastic syndromes (MDS) are a group of diseases where the production of blood cells by the bone marrow is disrupted.

The myelodysplastic syndromes, or MDS for short, are a group of diseases in which the production of blood cells by the bone marrow is faulty. It is a type of cancer and sometimes may be referred to as bone marrow failure. The bone marrow is located inside some of your bones and it is the factory where blood cells are made. It is here where the problem lies.

The bone marrow makes three main types of blood cells:

  1. Red blood cells that carry oxygen around the body
  2. White blood cells that fight infections
  3. Platelets that prevent bleeding

In addition to low blood counts, the myelodysplastic syndromes share a common tendency to develop into acute myeloid leukaemia (AML) over time. In MDS, the bone marrow has many immature abnormal cells called blasts. In some patients with MDS the number of blasts increases with time. Leukaemia (AML) is defined as having more than 20% blast cells.

The risk of AML occurring depends on the type of MDS, but some patients may never progress to AML.

The typical age for patients to develop MDS is around 75 years old. About 9 out of 10 patients are over 50 years at the time of diagnosis. Men are slightly more likely than women to be diagnosed with MDS.

What causes MDS?

The cause of MDS remains largely unknown, although there are many research groups around the world who are trying to improve our understanding of why it occurs and in whom. There are certain factors that may increase your chance of developing MDS and these include:

  • Previous chemotherapy with or without radiotherapy – this treatment may have been given in the past (usually for other cancers). It is thought that the treatment damages the bone marrow and may cause MDS in some patients. This is called secondary or therapy-related MDS, as it is secondary to the previous chemotherapy or radiotherapy.
  • Inherited disorders – very rarely, MDS can be inherited or may develop from another rare blood disorder. For this reason, young patients may be tested for any diseases that are linked to MDS. However, for the clear majority of patients, MDS will not be passed down to children and is not an inherited genetic disease.
  • Environmental factors – exposure to toxic chemicals such as benzene may marginally increase the risk of MDS, but such exposure is now uncommon.

Signs and symptoms of MDS

Symptoms vary from person to person and depend on which blood cells have become reduced in your bloodstream.

  • About 8 in 10 patients have anaemia, whilst about 2 in 10 present to their doctor with infections or bleeding. Anaemia is due to a lack of red blood cells (also referred to as low haemoglobin), which may lead to fatigue and shortness of breath, even on light exertion.
  • When your platelet count is low, you can suffer from easy bruising and bleeding. This can sometimes manifest itself as a rash on your skin. These are tiny bleedings under the skin called petechiae and often appear where clothes are tight fitting like around the ankles or waist. Nose or gum bleeds can also be a sign of a low platelet count.
  • Recurrent and persistent infections are another common symptom of MDS due to low white blood cell counts.

Some MDS patients have no signs or symptoms and are diagnosed by chance from a routine blood test.

Types of MDS

There are six broad types of MDS included in the current 2016 classification. These are:

  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 excess blasts (MDS- EB); MDS-EB-1 and MDS-EB-2
  5. MDS, unclassifiable (MDS-U)
  6. MDS with isolated del(5q) or with 1 additional abnormality

Prognostic Scoring System

There is an International Prognostic Scoring System (IPSS) which has been developed to help doctors to predict how likely MDS is to progress to acute myeloid leukaemia (AML). The IPSS is used to help doctors decide what treatment to recommend.

The IPSS Score is determined by adding the individual scores for the percentage of blasts in bone marrow and for the cytogenetic and blood test findings, and is used to assess the clinical outcome for the MDS patient.

A newer version is called the Revised IPSS (IPSS-R) and includes five risk groups, which are:

  1. Very Low: IPSS-R score 0 to 1.5
  2. Low: IPSS-R score more than 1.5 to 3
  3. Intermediate: IPSS-R score more than 3 to 4.5
  4. High: IPSS-R score more than 4.5 to 6
  5. Very: IPSS-R score greater than 6

Diagnosis of MDS

How are the myelodysplastic syndromes diagnosed?

  • Full blood count – Low blood counts are picked up by a simple test called a full blood count (FBC). The laboratory performing the test will then examine the blood cells on a slide (called a blood film) under the microscope. If you are found to have changes on the blood film that suggest MDS, you will usually be referred to a blood specialist (haematologist). It is important to rule out other causes of a low blood count so the doctor will ask general health questions and give you a physical examination.
  • Bone marrow test – As MDS is a disease of the bone marrow, a bone marrow test is usually needed to diagnose the condition or monitor response to treatment.

How long do I have to wait for the results?

Preparing the sample and analysing all the results can take two to three weeks. The bone marrow sample is examined by a doctor under a microscope to look for changes seen in MDS. Additional tests are often requested on the bone marrow sample, which may help to make the diagnosis and provide information about how the disease will behave (prognosis).

These tests include cytogenetics (sometimes called a ‘karyotype’), which is the study of the changes in the structure of the chromosomes in the affected cells. In addition, there is a general move towards molecular testing (to look for DNA mutations), which we hope will lead to more precision and therefore make care more personalised. However, we are still learning what the molecular changes may mean for MDS patients.

Prognosis of MDS

Prognosis refers to the expected outcome or survival from MDS and is therefore different from classification. Your prognosis can depend on many factors, including those not related to MDS, such as your general fitness and age. However, to allow your doctor to make the right treatment decisions, MDS doctors and scientists around the world have designed several scoring systems to help predict how your MDS is likely to behave. Over time, these scoring systems have evolved to give more accurate estimations. The most commonly used scoring system is the revised International Prognostic Scoring System (IPSS-R). This replaces the previous IPSS.

The IPSS-R score is calculated from:

  • Your blood count results at the time your MDS is diagnosed
  • The number of abnormal immature cells (blasts) in your bone marrow at diagnosis
  • The chromosome test results from your bone marrow at diagnosis

The calculator adds together the individual scores to give a final score, which puts you into one of the following IPSS-R risk groups:

  • Very low
  • Low
  • Intermediate
  • High
  • Very high

The risk groups describe the expected risk of developing acute myeloid leukaemia (AML) and expected survival. This helps your doctor to identify and discuss with you the best treatment choices for you as an individual.

Treatment of MDS

Treatment of MDS

Broadly speaking, treatment of MDS will include one or more of the following:

  • Supportive care – this aims to control the symptoms of MDS.
  • Non-intensive treatment – this treatment tries to slow down the progression of MDS and improve your blood counts.
  • Intensive chemotherapy – this involves giving high doses of chemotherapy in hospital.
  • Stem cell transplant – this gives your body new stem cells so it can grow new healthy blood cells in the bone marrow.

Unfortunately, most patients’ MDS cannot be cured but MDS can usually be controlled and often improved.

The first question that your doctor will ask themselves is whether there is a treatment option that has a chance of curing the MDS. The only treatments that can possibly cure MDS are either a stem cell or bone marrow transplant from another person or, very rarely, intensive chemotherapy.

If a stem cell transplant is an option for you, you will be identified early so that a search for donors can be started and a transplant considered at an early stage.

Questions to ask your medical team about myelodysplastic syndromes

We understand going through a blood cancer journey can be difficult. It may help to talk to a close friend or relative about how you are feeling. Here is a list of questions that may be useful to ask your medical team.

  • How can you tell if I have MDS?
  • What does that mean for me?
  • What tests will I need to have?
  • What will the tests show?
  • How long will the results take?
  • What sort of treatment will I need?
  • How long will my treatment last?
  • What happens if the treatment doesn’t work?
  • Can any treatments cure my MDS?
  • Will I need to be off work/college?
  • What are the chances of my MDS coming back?
  • Where can I get help dealing with my feelings?

Further downloads

We have free patient information available for MDS patients.

You can download our MDS booklet on our information pages here.

Alternatively, you can have the information delivered free of charge by requesting it through our resources page. 

Further support for MDS

MDS-UK is a dedicated support charity for MDS patients. You can find out more information on MDS on their website at

Published: November 2018

Review date: October 2021