The denomination of Myelodysplastic syndrome (or MDS) includes a series of illnesses that share the same problem; namely the stem cells of the bone marrow (which is charged with producing the blood cells) has a defect that causes the production of abnormal cells, incapable of realizing their normal functions, and produced at a lower quantity than normal
This alteration can affect one, two or all three of the cells derived from the stem cells (white blood cells, red blood cells and platelets) and could evolve over time into acute leukaemia (acute post-myelodysplastic leukaemia).
Occasionally, the MDS's are a consequence of a genetic anomaly as in Fanconi's Anaemia. In other cases, they are side effects from radiotherapy or chemotherapy treatment, or from the prolonged exposure to benzene, pesticides or insecticides. In the majority of cases it is difficult to determine the true root of the illness.
The risk of MDS increases with age, from middle age to the start of the 70's. It is more common among men than women and there are between 40 to 80 in a million new cases each year.
Paz, ex-myelodysplastic syndrome patient
The MDS's might not produce symptoms for many years and when they appear they can be completely unspecific, and impossible to distinguish from symptoms apparent in other illnesses. The main manifestations are produced by a deficit in the number of red blood cells (weakness, fatigue, dizziness, palpitations) or due to the deficit or poor functioning of the platelets (bruising, bleeding from different places) or the leukocytes (fever and frequent infections) . Occasionally the patient can experience abdominal pains as a consequence of the swelling of the spleen or the liver.
The diagnosis of the MDS is achieved by observing a microscopic image of the blood and the bone marrow. To obtain this precise bone marrow sample it will be necessary to carry out a puncture of the sternum or the hip bone, needle aspiration, and to carry out a bone marrow biopsy (the process will take place under a local anesthetic and will result in the obtaining of a small cylinder of the hipbone to study the structure of the bone marrow. It is also fundamental to perform cytogenetic studies to establish if the stem cells have any genetic condition that could be causing their poor condition.
After completing these studies it will be possible to determine the specific sub-type of MDS. The most recent classification distinguishes between 6 sub-types with varying prognosis, evolution, and treatment (simple refractory anaemia, refractory anaemia with ring sideroblasts, refractory cytopenia with multilineage dysplasia, refractory anaemia with excess blasts, 5q syndrome and other MDS's which are more difficult to classify).
Microscopic image of the bone marrow of a Myelodysplastic syndrome patient
The treatment of MDS's varies greatly from one patient to another and will depend on the type and intensity of the MDS, the age of the patient and the general state of health of the patient.
The mild cases do not usually require any treatment and can be stabilized for many years. In these cases it is merely necessary to periodically carry out analytical evaluations to control the evolution of the disease.
The only complete cure for the MDS's is a bone marrow transplant but the high toxicity level of this procedure means that it is limited to younger patients with a poor prognosis who have a compatible donor.
Patients who require treatment but are not eligible for a bone marrow transplant will have the following options:
• Growth Factors. They are laboratory produced substances for the body that have the capacity to stimulate the production of blood cells. They do not have the ability to cure MDS but they improve the blood count and can reduce the need for blood transfusions in some patients.
• Blood or Platelet Transfusions. The majority of patients require transfusions periodically to maintain the level of red blood cells and platelets. Although, these transfusions do not cure the disease they can alleviate some symptoms and contribute to a better general state.
• Immunomodulators. Enhances the anti-thymocyte globulin (ATG) and the cyclosporine which, occasionally, has proven successful among some patients.
• Cell differentiation inducers such as interferon alfa, cytarabine, amifostine, butyrates and some retinoic derivatives (vitamin A, retinoic and transretinoic acid, and vitamin D3) which have proved useful from some patients.
• Chemotherapy. Although 40-60% of the MDS patients achieve a remission of the disease (apparent normality of the bone marrow under microscopic examination) after receiving high dosages of chemotherapy, it is not usually a permanent remission and the side effects are notable. For that reason, chemotherapy should only be reserved for those patients who have a poor prognosis, candidates for a bone marrow transplant or for those who have developed acute leukaemia.
For more information:
• Myelodysplastic syndrome, resource of the National Cancer Institute
• Chronic myelomonocytic Leukaemia (CMML) and Juvenile Myelomonocytic Leukaemia (JMML), resource of The Leukaemia and Lymphoma Society
• Myelodysplastic Syndrome, resource of The Leukaemia and Lymphoma Society