What are they?
Myelodysplastic syndromes (MDS) are a group of diseases that affect normal blood cell production in the bone marrow. In MDS the bone marrow produces abnormal, immature blood cells called blast cells. These cells fail to mature properly are unable to work properly. They often die before they leave the marrow, or shortly after reaching the bloodstream. Without enough normal cells being produced by the marrow (red cells, white cells and platelets) people with MDS can become fatigued, more susceptible to infections, and to bleeding and bruising more easily.
There are several different types of MDS and the disease can vary in its severity and the degree to which normal blood cell production is affected. MDS is not a cancer. In about 30 per cent of cases however, MDS can progress to a form of cancer called acute myeloid leukaemia. It is therefore recognised as a pre-leukaemic disorder.
How common is it?
Overall, MDS is relatively uncommon, with an incidence of between 4 and 5 per 100,000 of the population; but in patients over the age of 60, this may increase to anything from 20 to 50 per 100,000 of the population. It is therefore one of the more common haematological disorders in the elderly.
It's difficult to be sure of the exact number of people who have MDS. This is because in many cases the disease develops slowly and people don't have any symptoms for a long time.
Who gets it?
MDS can occur at any age, but the majority of cases (over 90 per cent) occur in people over the age of 60 years. It occurs more frequently in men than in women.
What causes MDS?
In most cases, the causes of MDS remain unknown but there are likely to be a number of factors involved. MDS occurs as a result of a mutation (or change) in one or more of the genes that normally controls blood cell development. Like most leukaemias and other cancers, MDS becomes more common as we get older.
Certain factors have been identified that may put some people at increased risk of developing MDS. These include exposure to:
- high levels of industrial chemicals like benzene and other solvents over a long period
- toxic substances in tobacco smoke
- radiation, and certain types of chemotherapy used to treat other cancers.
What are the symptoms?
In general the types of symptoms that people experience depend on how severe their disease is and the type of blood cell which is most affected.
In many cases, MDS develops slowly, people don't have any symptoms particularly in the early stage and the disease is detected during a routine blood test.
The most common symptoms are caused by anaemia, due to a lack of red cells ; causing persistent tiredness, dizziness, paleness, or shortness of breath when physically active. Other symptoms may include:
- frequent or repeated infections and slow healing, due to a lack of normal white blood cells.
- increased or unexplained bleeding or bruising, due to a very low platelet count.
Many people have a combination of symptoms because more than one blood cell type is affected.
How is it diagnosed?
MDS is diagnosed by examining blood and bone marrow cells obtained from a blood sample, and bone marrow biopsy.
How is it treated?
Treatment for MDS depends on several factors including the exact type of MDS you have, your age and general health. Other factors affecting the likely course of your disease, and the chances of curing or controlling it for a given time, are also considered .
Many people, particularly in the early stage of disease don't need any treatment and the doctor may recommend regular checkups to carefully monitor their health.
The main treatment for the majority of people with MDS is supportive care. This includes the use of antibiotics, blood transfusions and in some cases growth factors to promote normal blood cell production in the bone marrow. This aim of this treatment is to prevent or treat complications arising from your disease or its treatment.
In more severe or progressive disease, chemotherapy may be used to control a rising blast cell count, and allow the bone marrow to resume normal blood cell production. This may involve low dose chemotherapy given in tablet form, or more intensive treatment using a combination of drugs given intravenously (into a vein), similar to those used to treat acute myeloid leukaemia.
Occasionally, a stem cell transplant may be used which increases the chance of cure for some people with MDS.
Side effects of treatment
All treatments can cause side effects. The type and severity however will vary between individuals, depending on the type of treatment used and how an individual responds to it. In general, more intensive treatment is associated with more severe side-effects. It is important to report any symptoms you are having to your doctor or nurse. In most cases they can be treated and are reversible.
Your doctor and nurse will discuss with you the possible side-effects of any treatments you need and how they can be managed.
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