Myelodysplastic syndrome

What is Myelodysplastic Syndrome? Types

Under the name of Myelodysplastic Syndromes are included a series of diseases that have a common characteristic: the bone marrow stem cells in charge of manufacturing all the blood cells have a defect that makes them produce abnormal cells that cannot perform their functions in a normal way.

This alteration can affect one, two or all three cell lines derived from the stem cell: red blood cells, white blood cells and platelets. This, in addition, can progress to acute leukemia.

The World Health Organization (WHO) establishes the following types of Myelodysplastic Syndrome:

1. Refractory cytopenia with unilinear dysplasiaà It is only anemia, plateletopenia or neutropenia.
2. Refractory sideroblastic anemiaà Is anemia or presence of sideroblasts.
3. Refractory cytopenia with multilineage dysplasia
4. AREB Type I à Presence of 5-9% blasts in the bone marrow
5. AREB Type II à More than 10% blasts in the bone marrow
6. MDS associated with isolated del(5q), or 5q- syndromes (a peculiar variety of myelodysplastic syndrome that affects women with refractory anemia, with elevated platelet counts, although with good prognosis and response to treatment).
7. Unclassifiable Myelodysplastic Syndromes

It should be noted that the incidence of myelodysplastic syndromes increases with age, the average age of onset being 70 years, and only 10% of patients are younger than 50 years. Moreover, it is more common in men than in women.

What are the symptoms?

Myelodysplastic syndromes can go on without symptoms for years and, when they appear, they can be nonspecific and can also be observed in other diseases. Usually, the main symptoms of myelodysplastic syndrome are related to:

1. Red blood cell deficiency:

• Weakness
• Fatigue
• Dizziness
• Palpitations

2. Platelet deficiency or malfunction:

• Bruising
• Hemorrhages of various locations

3. Deficiency or malfunction in leukocytes:

• Fever
• Frequent infections

Causes of Myelodysplastic Syndrome or why it occurs

Although the causes of myelodysplastic syndrome are not entirely clear, a number of risk factors can be considered that may be related to the development of the disease, which are:

• Having received chemotherapy treatment
• Geneticsà Some bone marrow problems are caused by mutation of inherited genes. Thus, people with some inherited syndromes are more likely to have myelodysplastic syndrome. Some of these inherited blood disorders are Fanconi anemia, Schwachman-Diamond syndrome, Diamond Blackfan anemia, familial platelet disorder or severe congenital neutropenia.
• Smoking increases the risk of the disease
• Environmental exposure to certain chemicals and radiation.
• Age, since the risk of suffering from the disease increases with age.
• Sex, as men are more predisposed to the disease.

Can it be prevented?

The first measure to prevent myelodysplastic syndromes is to avoid smoking. People who do not smoke are less likely to suffer from this type of disease.

On the other hand, in the case of cancers, chemotherapy and radiation are often used as treatment measures. Some physicians try to avoid chemotherapy drugs that may cause myelodysplastic syndromes.

Avoiding exposure to certain cancer-causing chemicals (benzene) may also be a good preventive measure.

What does the treatment consist of?

The treatment of myelodysplastic syndromes is variable, depending on the type of syndrome suffered by the patient, his age and state of health.

Thus, moderate cytopenias do not usually require treatment, and remain stable with periodic analytical controls.

The only curative treatment is allogeneic bone marrow transplantation (from a family donor, unrelated but compatible, or umbilical cord blood). However, it is a toxic procedure that is sometimes not suitable for elderly patients. In those patients who cannot be recipients of bone marrow transplantation it is recommended:

• Blood or platelet transfusions à It is a treatment that allows them to maintain the level of red blood cells and platelets correctly. Although it does not cure the disease, it can improve the symptoms. They are usually indicated in patients with appreciable bleeding but are not recommended in the long term because the patient may present refractoriness or rapid destruction of administered platelets.

• Growth factorsà These are substances from the body itself, synthesized in the laboratory and capable of stimulating the production of blood cells. The most commonly used are: erythropoietin (EPO) to increase red blood cell production and thus reduce anemia, and G-CSF (colony-stimulating factor), which increases the number of granulocytes and reduces infections.

• Immunomodulatorsà These improve anemia in 45% of cases.

• Immunosuppressive agents, such as antithymocyte globulin and cyclosporine.

• Hypomethylating agents, such as azacitidine, which achieves transfusion independence in 40-60% of patients.

• Chemotherapyà Recommended when the number of blasts exceeds 10-20% in the bone marrow and the myelodysplastic syndrome is developing into post-myelodysplastic acute leukemia.