Myelodysplastic syndrome and myeloproliferative disorders

As doctors have found out more about these two conditions, how they are thought of has changed. They are now usually described as cancers or pre-cancers.

These conditions cause too many of a single type of blood cell to be made. This upsets the normal balance of blood cells, as there is less room in the bone marrow for making the other types:

• Myelodysplastic syndrome
• Myeloproliferative disorders.

Find out more about: Biology of blood, blood cancers and blood disorders.

Myelodysplastic syndrome (MDS)

This is a group of conditions affecting different types of blood cells. These are rare conditions, most often diagnosed in people over 65; they are more common in men than women (1). How these conditions are thought of has changed over time. They are often now described as cancers or pre-cancers.

What is it?

In MDS, the bone marrow does not make blood cells as well as it should (2). It makes too many of one or more types of blood cell, but they are abnormal and do not work properly (2,3). They crowd out the other normal blood cells, so your bone marrow does not make enough normal cells. If not treated, some types of MDS can transform into acute myeloid leukaemia (AML)(2).

We do not know exactly what causes MDS, but it is likely to be a number of factors working together. Some people have a gene change or mutation. Smoking and contact with a chemical called benzene may also be a factor. Younger people can develop MDS if they have had chemotherapy or radiotherapy to treat cancers (4).

Symptoms

Some people do not have any symptoms of MDS; it is diagnosed by chance when they are having a blood test for something else.

You may:

• look pale, be short of breath and feel very tired because of low red blood cells (anaemia)
• have infections that are hard to get rid of or keep coming back, because of low white blood cells
• have bruises or bleeding, such as nosebleeds because of low platelets, blood cells that help the blood to clot.

Treatment

The type of treatment you have depends on:

• the type of MDS you have
• your test results, and
• your age and general fitness.

If you do not have any symptoms, your doctor may just monitor your health and keep treatment in reserve for when you need it (6,7).

If you have symptoms, you are likely to have transfusions to top up your red blood cells and platelets. You may also have blood cell growth factor injections to boost low blood cell counts (7).

Your doctor may suggest chemotherapy or a drug called lenalidomide to control the MDS (7).

If you are young and fit enough, you may be offered a stem cell transplant using blood cells from a donor: an allogeneic transplant. This is the only way to try and cure MDS, but it is hard to get through so you will only have a transplant if there is a significant risk that your MDS could transform into leukaemia (7).

Outlook

As a group of conditions, MDS can vary so much that it is not really helpful to look at overall statistics. It is best to ask your own specialist as they have all the information on your case and treatment.

Doctors group MDS into different risk categories, depending on test results. People with mild MDS that is low risk can live with it for many years (8).

Myeloproliferative disorders

A myeloproliferative disorder means your bone marrow is making too many of one type of blood cell. There are four main types (8):

• chronic myeloid leukaemia (CML)
• polycythaemia vera (PV)
• essential thrombocytosis (ET) – also called primary thrombocythaemia
• primary myelofibrosis (PMF).

Polycythaemia vera (PV)

Polycythaemia vera is rare but becomes more common with age. It is very rarely diagnosed in people under 40 and is commonest in people over 70; it is slightly more common in men (10).

What is it?

With PV, your bone marrow makes too many red blood cells (9). You may also have too many white blood cells and platelets - cells that help the blood clot. Over time, the bone marrow can become dense with scar tissue: myelofibrosis (11), so it may not make enough blood cells of any type. If advanced, PV can also transform into acute myeloid leukaemia (12).

We do not know what causes PV. Nearly everyone diagnosed has a particular gene change or mutation, but PV does not often run in families. You do not inherit the gene change: it happens after you have been born (13).

Symptoms

Some people do not have symptoms. PV is diagnosed after a routine blood test (14). PV increases your risk of blood clots and some people are diagnosed after a heart attack or stroke.

If you have symptoms, you may have:

• other signs of a blood clot, such as a DVT (deep vein thrombosis) (14)
• had problems with bleeding in the past, for example, a bleeding stomach ulcer or blood in your poo (14,15)
• headaches, dizziness or blurred vision caused by ‘thickened’ blood (15)
• severe itching, which may start when your skin comes into contact with warm water (14)
• redness, pain or burning sensation in fingers and toes (14)
• a red complexion (14).

Treatment

The aim of treatment is to reduce your risk of blood clots (16). The type of treatment depends on your risk of clots. This is affected by your age and whether you have had a blood clot in the past (12).

Low or moderate risk of clots
Your doctor will give you low-dose aspirin. You are also likely to have some blood removed, up to two or three times a week. This is like giving blood, with a needle in your arm, draining the blood off into a bag (12).

High risk of clots
You have the same treatment as low-risk, but with medication to reduce the number of red cells. This is often a chemotherapy tablet (12).

Densely fibrosed bone marrow (myelofibrosis) or PV that is transformed into leukaemia
Your doctor may suggest a stem cell transplant using cells from a donor: an allogeneic transplant (17,18). You can only have this treatment if you are young and fit enough, as it is hard to get through (17).

Outlook

Polycythaemia vera (PV) is a long-term, slowly developing condition. On average, people with low-risk PV live for around 30 years after diagnosis. Even with high-risk PV, the average survival time is over 10 years (19).

Essential thrombocytosis (ET)

Essential thrombocytosis (ET), also called primary or essential thrombocythaemia (2), is a rare disease that can be diagnosed at any age. It is most common in people between 50 and 70 (20) and more common in women (1).

What is it?

With ET, your bone marrow makes too many platelets: cells that help your blood clot (2). After many years, fewer than one in 20 people (less than five) with ET develop scar tissue, myelofibrosis, in their bone marrow (21). With myelofibrosis the bone marrow may not make enough of any type of blood cells. If advanced, ET can also transform into acute myeloid leukaemia (22).

We do not know what causes ET. Nearly everyone diagnosed has a particular gene change or mutation, but ET does not usually run in families. You do not inherit the gene change: it happens after you are born (23).

Symptoms

As many as half of those with ET do not have any symptoms; it is diagnosed after a routine blood test (24). If you do have symptoms, they may include (25):

• headache, dizziness or lightheadedness
• problems related to blood clots, such as heart attack, stroke or DVT
• mottled skin, particularly on the legs
• burning pain and redness in the feet and hands
• increased risk of miscarriage.

Treatment

If you do not have symptoms, you may not need any treatment. Your doctor will monitor your condition with regular blood tests (26). To control symptoms, most people have low-dose aspirin (24).

As well as low-dose aspirin, people over 60 or with a history of blood clots have treatment with medication to reduce the number of platelets. This is usually a chemotherapy tablet (26). Your doctor may also suggest an anti-clotting drug, such as heparin or warfarin (24).

For densely fibrosed bone marrow - myelofibrosis - your doctor may suggest a stem cell transplant using cells from a donor: an allogeneic transplant (27,28). If you are well enough, your doctor may also suggest a donor stem cell transplant for ET that has transformed into leukaemia (29).

Outlook

Most people with ET have a normal lifespan. It is only really a problem if you develop myelofibrosis or leukaemia, which only happens in one or two out of 20 people at most (30).

Primary myelofibrosis (PMF)

Primary myelofibrosis (PMF) is a rare disease that is usually diagnosed in middle to older age. The average age at diagnosis is 65; it is more common in men (31).

What is it?

In PMF, scar tissue forms in the bone marrow (30). As the bone marrow becomes more and more fibrous, it is less able to make blood cells. You do not have enough white cells, red cells, or platelets - cells that help the blood clot. Eventually, the bone marrow may fail altogether (32).

We do not know what causes PMF (32).

Symptoms

If you have PMF, you may (33):

• feel very tired, weak and short of breath because of a low red blood cell count (anaemia)
• have fevers and sweating at night
• lose weight
• lose your appetite or feel full because of a swollen liver or spleen
• have bone pain
• bruise or bleed easily because of a low platelet count.

Treatment

PMF treatment depends on whether you have symptoms and how fit you are. If you do not have any symptoms, your doctor may just monitor your health and keep treatment in reserve for when you need it (34).

The only way to cure PMF is to have a stem cell transplant using cells from a donor - an allogeneic transplant (34). So if you have symptoms when you are diagnosed, your doctor may arrange tests to see if you are fit enough for such intensive treatment (26).

If you are not fit enough for a stem cell transplant, you will have treatment with drugs that can help to control your symptoms. If you have abdominal pain or discomfort, your doctor may suggest an operation to have your spleen removed, or radiotherapy to shrink it (34).

Outlook

The outlook of PMF varies greatly. On average, people live for around five years after their diagnosis. But for some it can be as little as a year and for others up to 30 years (35). It is best to ask your own specialist as they have all the information on your case and treatment.