Myelodysplastic Syndrome

What is Myelodysplastic Syndrome (MDS) of Childhood?

Myelodysplastic syndromes (MDS) are a heterogeneous group of disorders 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. They represent 5 – 10% of all myeloid malignancies in children. MDS is characterized by ineffective haematopoiesis and increased cell death.

MDS can affect children as well, although the incidence is less than 5%. Anemia is the commonest manifestation of MDS in adults, but low white cell or platelet count is commoner in children.

The bone marrow is more often less cellular like Aplastic anemia and this entity is called Refractory Cytopenia of Childhood (RCC). This condition has to be differentiated from Aplastic Anemia.

What are the symptoms of Myelodysplastic syndromes?

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

Classification of Myelodysplastic syndromes

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
• %age of blasts in bone marrow
• Abnormalities in the chromosomes

Based on these three parameters, an International Prognostic Scoring System has been developed.

Diagnosis

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.

How do we treat Myelodysplastic Syndrome (MDS)?

The Only Curative Treatment of MYELODYSPLASTIC SYNDROME (MDS) Is an Allogeneic BMT

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 done for Myelodysplastic Syndrome (MDS)?

The BMT should be done 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

Who can be a donor for BMT for patients with MDS?

Although we prefer a matched family donor, a Half matched (Haploidentical) family donor or an unrelated cord blood are suitable alternatives.

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.