 | Incidence | | | 1 /100 000/year |
| UK Incidence | | | 3,250/year |
| Median age | | | 70 years |
| M:F ratio | | | >1 |
| | |
|  |  | Disease Name; |
Myelodysplastic Syndromes
| Synonyms; |
Refractory anaemia, Refractory anaemia with ring sideroblasts, Refractory anaemia with excess blasts, Refractory anaemia with excess blasts in transformation, Chronic myelomonocytic leukaemia
| Description; |
The myelodysplastic syndromes (MDS) is a group of diseases in which the production of blood cells by the bone marrow is disrupted. In contrast to leukaemia, in which one specific type of blood cell (the white cell) is produced in excessively large numbers, the production of any, and sometimes of all, types of blood cells is affected.
The myelodysplastic syndromes were formerly referred to by many names including preleukaemia. The term Preleukaemia is no longer used because it is very misleading. Although a minority of patients with MDS develop acute leukaemia, most do not. When leukaemic transformation does occur, it is to acute myeloid leukaemia1. This form of acute myeloid leukaemia is typically more difficult to treat than primary acute myeloid leukaemia (cases arising in patients with no previous bone marrow disease).
The bone marrow in myelodysplastic syndrome is typically more active than normal and yet the numbers of blood cells in the circulation are reduced. This is because most of the cells being produced in the bone marrow are defective and are destroyed before they leave the bone marrow to enter the blood stream. The hallmark of the myelodysplastic syndromes is the combination of a hyperactive marrow with low blood cell counts. A reduction in numbers of all types of blood cell is called pancytopaenia.
There is a degree of overlap between MDS and aplastic anaemia. It may sometimes be difficult to distinguish between aplastic anaemia and a subtype of MDS in which the marrow is underactive. This form of MDS is called hypoproliferative or hypoplastic myelodysplastic syndrome. Fortunately, discrimination between these conditions is not critical for treatment planning.
Chronic myelomonocytic leukaemia (CMML) is a distinct sub-type - a separate factsheet on this is available.
Last updated 22/02/2010 |
