Formerly called pre-leukemia, myelodysplastic syndrome or MDS refers to a group of hematological ailments that occur due to abnormal production or functioning of the myeloid blood cells, i.e., malformed or malfunctioning blood cells. Myelodysplastic syndrome primarily manifests as anemia because of reduced RBC production.
Blood cells are made in the bone marrow. Any kind of problem in the stem cells of the bone marrow can cause its progressive failure and decrease in the count of blood producing cells eventually resulting in low blood count. Subsequently, there is an increase in the number of immature myeloblasts which cannot form into mature RBCs. In nearly 30 percent of people with myelodysplastic syndrome, the condition may deteriorate and advance to acute myelogenous leukemia. Such progression may happen in some months or some years after the initial development of MDS.
Myelodysplastic syndrome has no known cure. Treatment is focused on managing the adverse symptoms and preventing the onset of health complications. Bone marrow transplant can help increase the life expectancy in some patients.
Types of myelodysplastic syndrome
Myelodysplastic syndrome can be categorized into many different subtypes according to the kind of blood cells that get affected, i.e., WBCs, RBCs, and/or platelets. The subtypes of myelodysplastic syndrome are:
- RCUD/Refractory cytopenia with unilineage dysplasia: In this, the count of one type of blood cell is lower than that of others. The blood cells appear abnormal when investigated under a microscope.
- RCMD/Refractory cytopenia with multilineage dysplasia: In this, 2 out of the 3 types of blood cells are abnormal and under 1 percent of the blood system consists of blasts or immature cells. It carries the risk of progressing into acute myeloid leukemia.
- Refractory Anemia: In this, the RBC precursors elicit under 5 percent pathological problems and myeloblasts.
- RAEB/Refractory anemia with excessive blasts: This type of myelodysplastic syndrome is further divided into type 1 and 2. Any of the 3 types of blood cell may appear abnormal and have a low count. Very immature blood cells or blasts can be seen in blood. Nearly 20 percent myeloblasts occur in the bone marrow.
- RARS/ Refractory anemia with ringed sideroblasts: In this, the RBC precursors have high iron content and are called ringed sideroblasts. It features low RBC count and under 5 percent myeloblasts.
- RAEB-T/Refractory Anemia with Excess Blasts in Transformation: In this, the bone marrow may feature myeloblasts between 21 and 30 percent.
- Myelodysplastic syndrome with isolated del(5q) chromosome anomaly: In this, the DNA exhibits some obvious anomalies along with low RBC count. It is less likely to progress into acute myeloid leukemia.
- Myelodysplastic syndrome, unclassified: In this, platelets or WBCs appear abnormal. Older blood cells of any 1 of the 3 types may be lower in numbers. This type of myelodysplastic syndrome is quite uncommon.
Patients may not experience any signs and symptoms during the early phases of the disease. Over time, myelodysplastic syndrome may cause the below listed symptoms:
- Easy or unusual bruising or bleeding.
- Bleeding can trigger the development of miniscule tiny reddish spots just under the surface of the skin.
- Breathing problems such as breathlessness
- Anemia can result in very pale skin.
- Chronic and recurrent infections
- Exhaustion and fatigue
- Sore throat
- Chest pains
- In some patients, myelodysplastic syndrome may eventually progress to cancer of the blood cells, i.e., leukemia.
Myelodysplastic syndrome is caused due to disruption in the production of blood cells by the bone marrow. The cause of such disruptions is not known.
Problems in the process of blood cells creation results in production of incomplete, immature, and faulty blood cells. The cells may die when in the bone marrow itself or after they get passed into the blood stream. Over time, the count of faulty blood cells or blasts becomes more than the number of healthy blood cells. This is what then causes anemia, infections, excessive bleeding, and other abnormalities associated with myelodysplastic syndrome.
Myelodysplastic syndrome can also occur due to cancer treatments like radiation therapy or chemotherapy or due to exposure to dangerous toxins and chemicals.
The below listed risk factors can pose increased threat to development of myelodysplastic syndrome:
- Contact with lead, mercury, and other heavy metals.
- Aging. People over the age of 60 are more susceptible.
- Smoking for long periods of time.
- Exposure to pesticides, industrial chemicals, etc.
- Men are more prone to developing myelodysplastic syndrome than women.
There is no cure for myelodysplastic syndrome. Treatment is aimed at alleviating symptoms and preventing complications. A few treatment options are as follows:
- Medications: Different drugs can be used to increase the count of healthy blood cells as well as overcome the effects of the adverse symptoms.
- Medicines called growth factors help improve the production of healthy cells. Increased number of healthy WBCs will then help overcome infections and other related problems.
- A few types of medicines can help convert young cells into mature healthy cells. However, these drugs may not work in all patients; it may actually end up worsening a case of myelodysplastic syndrome.
- Immunosuppressant medications can help inhibit the actions of the immune system.
- Doctors may prescribe lenalidomide to overcome the effects of genetic problems associated with some forms of myelodysplastic syndrome.
- Iron chelation therapy. In this, deferasirox pills or intravenous deferoxamine medications are prescribed to lower the high blood iron levels.
- Blood transfusion: It helps improve the count of all the 3 different kinds of blood cells. Doctors will keep a check on the number of blood transfusions as numerous transfusions can result in elevated levels of iron in blood.
- Bone marrow stem cell transplant: In this, all bone marrow cells are destroyed via chemotherapy. Stem cell transplant method is then used to replace the cells with the cells obtained from a healthy donor.
Myelodysplastic syndrome life expectancy
- Mild myelodysplastic syndrome marked by normal chromosomes, low blast count, and minor cytopenias comes with a mean life-expectancy of about 19 to 25 months. It can be longer after carrying out stem cell transplant.
- The mean life expectancy of MDS marked by chromosomal anomalies, serious cytopenias, and elevated immature cells count in blood and bone marrow is about 7 to 12 months. Extensive treatment can only increase the lifespan by no more than 10 years.
- In similar age groups, men have a significantly shorter life expectancy than women. Life expectancy is also dependent on the type of myelodysplastic syndrome affecting the patient.