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Myelodysplastic syndromes (MDS)

myelodysplastic syndrome cancer

What is MDS?

To expand it, it stands for myelodysplastic syndromes. What do we understand by that? It means that the blood cells are either defective or get destroyed earlier than they are supposed to which reduces the net functional blood cells.

The bone marrow is a spongy yellowish white material present between the long bones. This bone marrow is a factory for blood cells. There are three types of blood cells that our body produces- red blood cell (RBC)s or erythrocytes, white blood cells (WBC) or leukocytes, and platelets or thrombocytes.

MDS may affect the formation of any or all the blood cells.

How does it happen?

Myelodysplastic syndromes are said to occur mainly due to some sort of genetic mutations in the bone marrow stem cells. The bone marrow, in a healthy individual synthesizes immature blood cells which are known as blast cells. These cells, later on mature and perform the normal functions.

In a mutated gene, the immature blood cells may not mature and accumulate in the bone marrow. They may also have a shorter life span. These defects reduce the total blood cells in circulation and lead to various complications.

Who does it mainly affect?

Myelodysplastic syndromes are said to affect the older individuals who are over the age of 60. About 7 out of 100,000 people are diagnosed with MDS and 4 new people every year.

What are the potential causes of MDS?

When there is no specific causative agent for MDS, it is called primary MDS.

When the cause is of a known triggering agent, it is called as secondary MDS.

  • Radiation: Since MDS is a disorder that involves genetic variations, the primary cause is radiations which may cause any genetic mutation. Radiation can be both therapeutic (example after radiation therapy for cancer) or accidental exposure (radioactive plants, atomic testing).
  • Chemical factors: Chemical agents also are known to cause MDS. Chemotherapy which involves alkylating agents, melphalan, busulfan, chlorambucil. Other chemical agents like benzene, which are exposed to the human cells through professions can also cause the disorder. The professions which may lead to increased risk of MDS are labelled “at risk” jobs. These include painters, coal miners, embalmers.
  • Smoking: there is insufficient evidence to confirm if smoking causes MDS, but it is seen that smokers are at 1.6 times the risk of being affected by MDS than non-smokers.
  • Genetic disorders: patients who are diagnosed with Down’s syndrome are said to be at an increased risk of being affected.

What are the types of myelodysplastic syndromes?

The World Health Organisation has classified MDS into different types based on the number and type of affected blood cell.

  • TYPE 1: MYELODYSPLASTIC SYNDROME WITH UNILINEAGE DYSPLASIA: only one blood type – red blood cells, white blood cells or platelets are affected by the disorder.
    The other blood types are of normal levels.
    This type of MDS is quite rare and rarely progresses to acute myeloid leukaemia, a type of blood cancer.
    In the earlier classification, it was known as refractory cytopenia with uni-lineage dysplasia and the individual diseases were called refractory anaemia, refractory neutropenia, and refractory thrombocytopenia.
  • TYPE 2: MYELODYSPLASTIC SYNDROME WITH MULTILINEAGE DYSPLASIA: two or three blood types are affected.
    About 5% of the cells are normal and are found in the bone marrow in the early blast stage and are rare in the bone marrow.
    This is the most common type of MDS and was earlier referred to as refractory cytopenia with multilineage dysplasia.
  • TYPE 3: MYELODYSPLASTIC SYNDROME WITH RING SIDEROBLASTS: in this type of MDS, many of the early red blood cells are sideroblasts.
    Sideroblasts are red blood cells which atypical, abnormal red blood cells which have iron deposition in the mitochondria surrounding the nucleus like a ring.
    At least 15% of the early red blood cells will be ring sideroblasts.
    It is due to the mutation of SF3B1 gene.
    This type is further sub-divided into two groups:
    1. MDS-RS with single lineage dysplasia– only one cell type is affected.
    2. MDS-RS with multilineage dysplasia– two or three cell types are affected.

          It is a rare type of MDS which rarely turns into AML.

          It was previously referred to as refractory anaemia with ring sideroblasts.

  • TYPE 4: MYELODYSPLASTIC SYNDROME WITH EXCESS BLAST CELLS: in this type of condition, the patient has increased blast cells or immature cells either circulating in blood or in the bone marrow.
    The patient also has reduced levels of any of the blood types.
    This group is also sub-divided into two more groups:
    1. MDS-EB1– blast cells make up either 5-9% cells in the bone marrow or 2-4% cells in the blood.
    2. MDS-EB2– blast cells make up 10-19% cells in bone marrow or 5-19% cells in blood.

          This type of MDS occurs one in 4 cases.

          It has the highest tendency to turn to AML, with the risk being higher for MDS-EB2.

  • MYELODYSPLASTIC SYNDROME WITH del5(q): in this type of MDS, the patients bone marrow cells are missing a part of the chromosome 5. They could also have any other chromosomal abnormality which does not include loss of part of chromosome 7.
    The patient has low count of one or two types of blood cells.
    This type of MDS is rare and affects women more than men.
    They rarely develop AML and go on to live a healthy life. 
  • MYELODYSPLASTIC SYNDROME, UNCLASSIFYABLE: this type of MDS shows clinical findings that do not match with finding of the other groups.
    It is rare and not enough research to determine its relation to AML.

What are the symptoms of MDS?

The symptoms can be grouped based on the cell type/types that are affected.

  1. LOW RED BLOOD CELLS:
    • It is also known as anaemia
    • Patients experience fatigue and tiredness most of the time.
    • Patients are easily exhausted.
    • Heart palpitations are felt
    • Shortness of breath.
    • Pale skin or pallor
    • Severe cases show cardiovascular symptoms including chest pain.
  2. LOW WHITE BLOOD CELLS:
    • Increased susceptibility to bacterial infections (skin, sinus, lung, urinary infections).
    • Fever may accompany the
  3. LOW PLATELET COUNT:
    • Increased tendency to bleed
    • Petechiae: bleed spots of minor capillaries
    • Ecchymosis
    • Bruises
    • Epistaxis: frequent nose bleeds.

How to detect MDS in a patient?

Certain tests are performed to determine MDS and the type. They are:

  • FULL BLOOD COUNT AND BLOOD SMEAR: a complete examination of blood sample on a slide (blood smear) will show the structural abnormalities, clumping of the platelets, increased blast cells, sideroblasts etc.
  • BLOOD TESTS: to eliminate the other diseases like lupus, hepatitis, folic acid deficiency, vit B12 deficiency, HIV, etc.
  • BONE MARROW EXAMINATION: this would reveal the key feature of MDS which is bone marrow dysplasia.
  • CYTOGENETICS: this is simpler known as chromosome study. It will reveal the genetic abnormalities which have led to MDS. It is done by drawing bone marrow from syringe cannula.
  • TESTING FOR COPPER DEFICIENCY: copper deficiency resembles the signs and symptoms of MDS.

What are the complications that can occur from MDS?

  • ANAEMIA: reduced number of red blood cells.
  • RECURRENT INFECTIONS: due to the reduced number of white blood cells.
  • BLEEDING: due to reduced number of platelets which cause bleeding that won’t stop.
  • INCREASED RISK OF CANCER: myelodysplastic syndrome has shown to have an increased risk of acute and sometimes chronic myeloid leukaemia.

What are the methods of management and treatments available for MDS?

There are two main methods of management- through medicines (pharmacological) and through surgery (surgical).

PHARMACOLOGICAL METHODS:

  1. Hypomethylating drugs:
    • Azacytidine
    • Decitabine
  2. Conventional drugs:
    • Cytarabine
    • Daunorubicin
    • Idarubicin
  3. Immunomodulatory drugs:
    • Lenalidomide
  4. Synthetic growth factors:
    • Epogen
    • Eprex
    • Procrit
  5. Antibiotics:

SURGICAL METHODS:

  1. Stem cell transplantation: this is a surgical procedure in which the defective bone marrow is replaced with a healthy stem cell transplant. These stem cells later synthesise healthy and normal blood cells.
    This treatment comes with a lot of risk factors.
    There are two types of stem cell transplant- AUTO and ALLO transplants.
    AUTO uses the patient’s own stem cells.
    ALLO uses stem cells donated by the donor. A close match is required for this to work.
  2. Blood transfusion: this can help to manage anaemia and thrombocytopenia in patients.

What is the prognosis for MDS?

Prognosis is the prediction of the outcome and the success of it.

Factors that indicate a good prognosis for MDS:

  • Younger age
  • Lower blast count
  • Ringed sideroblasts
  • Cells without complex chromosomal abnormalities

Factors that indicate poor prognosis:

  • Older age
  • Severe deficiency in white blood cells and platelets
  • High blast counts
  • More than 3 chromosomal abnormalities
  • Defects in chromosome 7

What is the cost of treatment in India for MDS?

Indian doctors are medically advanced with years of experience in handling difficult and complex cases of a wide variety. This treatment comes at a lower price than most developed countries in the world while still having advanced technologies and support.
The cost of treatment in India (with respect to stem cell transplant) is around $10800 to $12250.