INHERITED METABOLIC DISORDERS
A myelodysplastic syndrome is a type of cancer in which the bone marrow does not make enough healthy blood cells and there are abnormal (blast) cellsin the blood and / or bone marrow.
Myelodysplastic syndromes (MDS) are conditions that can occur when the blood-forming cells in the bone marrow are damaged. This damage leads to low numbers of one or more type of blood cells.
MDS is a spectrum of diseases which are characterised by anemia, thrombocytopenia and low white cell counts along with dysplasia (meaning abnormal looking) blood cells in both peripheral blood and bone marrow. They are early stages of leukemia. Many develop acute leukemia eventually, but most die because of bleeding or infections before development of leukemia.
This is commonest disease developing as a side-effect of treatment of other cancers with chemotherapy and radiotherapy and is called Therapy-related MDS or t-MDS.
Myelodysplastic syndromes may or may not have symptoms. Few common symptoms are:
- Shortness of breath
- Weakness or feeling tired.
- Having skin that is paler than usual
- Easy bruising or bleeding
- Petechiae (flat, pinpoint spots under the skin caused by bleeding)
- Fever or frequent infections
This is based on number of cell lines affected ( i.e. 1, 2 or 3) and the number of blasts in the bone marrow. They are thus classified as:
- Refractory Anemia
- Refractory Cytopenia with Multilineage Dysplasia
- Refractory Anemia with Ring Sideroblasts
- Refractory Anemia with Excess Blasts
The three most important parameters determining the outcome in the patients with Myelodysplastic Syndrome (MDS) are
- Number of Cytopenias
- % of blasts in bone marrow
- Abnormalities in the chromosomes
Based on these three parameters, an International Prognostic Scoring System has been developed.
The diagnosis is made by careful and diligent examination of Blood and Bone Marrow samples by an experienced Hematologist. Along with that study of chromosomes from the bone marrow sample is a must:
The abnormalities of chromosomes are divided as GOOD or BAD:
- Good: normal, -Y, del5q, del20q
Bad: Monosomy i.e. deletion of one of the pair of chromosomes, mostly chromosomes 5 and 7 and other complex abnormalities.
The Only Curative Treatment of MYELODYSPLASTIC SYNDROME (MDS) Is an Allogeneic Bone Marrow Transplant.
How do we condition patients with Myelodysplastic Syndrome (MDS) for BMT?
As the disease is mostly seen in older patients, a Reduced Intensity Conditioning is preferred.
When should BMT be carried out for Myelodysplastic Syndrome (MDS)?
The BMT should be carried out early, before the onset of life threatening infections or multiple transfusions, leading to severe iron overload.
Some of the patients with higher blast count or abnormal chromosomes might benefit from a short course of chemotherapy before BMT
However a HAPLOIDENTICAL DONOR, who has Natural Killer Cell mismatch with the patient, provides the best chance of cure.
Other Treatments: Older patients who are not fit for a BMT can be treated in the following way:
- Red Cell and Platelet Transfusions as needed
- Erythropoetin injections to reduce blood transfusion requirements
- Hypomethylating agents such as Azacytidine or Decitabine which are milder forms of chemotherapy.