Myelodysplastic syndromes, also called myelodysplasia or MDS, is the name for a group of conditions that cause the number of normal blood cells to drop.
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In these syndromes, the bone marrow does not make enough normal blood cells, and the blood cells that are produced do not work as they should.
Myelodysplastic syndromes are more common in people over the age of 70, but they can occur in people of any age.
The Types of Myelodysplastic Syndromes
There are many different types of MDS, with six broad types of MDS currently included in the World Health Organization’s classification. These include:
- MDS with single lineage dysplasia (MDS-SLD)
- MDS with multi-lineage dysplasia (MDS-MLD)
- MDS with ring sideroblasts (MDS-RS)
- MDS with excess blasts (MDS-EB, MDS-EB-1, MDS-EB-2)
- MDS, unclassifiable (MDS-U)
- MDS with isolated del(5q) or with one additional abnormality.
There is also a system that scores the likely outcome of the disease, called the Revised International Prognostic Scoring System (IPSS-R). The five risk groups include:
- Very low risk
- Low risk
- Intermediate risk
- High risk
- Very high risk.
The number of immature cells in the bone marrow and blood, the blood cell levels, and chromosomal changes all affect the IPSS-R score.
Causes of Myelodysplastic Syndromes
It is not known what causes the majority of myelodysplastic syndromes, and these cases are called primary MDS.
Exposure to certain chemicals can make a person more likely to develop myelodysplastic syndromes. Benzene, which is used in the rubber industry, petrol, and cigarette smoke, is one of the chemicals that can cause myelodysplastic syndromes.
In rare cases, myelodysplastic syndromes can be caused by radiotherapy or chemotherapy treatment for cancer. These cases are called secondary MDS or treatment-related MDS.
Symptoms of Myelodysplastic Syndromes
Some cases of myelodysplastic syndromes are asymptomatic, meaning a person does not experience any symptoms of the disease. Those who do experience symptoms will usually have mild symptoms that gradually become worse. These symptoms can include:
- Fatigue
- Breathlessness due to a low red blood cell count, known as anemia
- Frequent infections because of low levels of white blood cells
- Bleeding and bruising easily because of a low platelet count
- Pain or discomfort in the stomach.
Treatments for Myelodysplastic Syndromes
Myelodysplastic syndromes will be treated by a hematologist and a medical oncologist, among several other medical specialists. A hematologist is a doctor who treats blood disorders, and a medical oncologist is a doctor who treats cancer with a range of medications.
The main types of treatment for myelodysplastic syndromes are:
- Supportive therapy
- Immunotherapy
- Growth factors
- Chemotherapy
- Stem cell transplants
The type of treatment a person receives is based on the type of MDS they have, as well as their overall health and their age.
Supportive therapy
Supportive therapy aims to treat or prevent the symptoms of myelodysplastic syndromes, as well as any complications that may occur. Supportive therapy does not treat the MDS itself. Other treatments may be used alongside supportive therapy for MDS.
Treating the anemia that develops because of MDS is one of the main focuses of supportive MDS therapy.
Increasing red blood cell counts
Some people with MDS may get injections of erythropoietin, which is a growth factor that can encourage the bone marrow to make new red blood cells.
Red blood cell transfusions can also be helpful in supportive MDS therapy. This involves a person receiving blood donated by another person. A drug known as a red blood cell maturation agent can help people who have not had success with erythropoietin growth factors and require a regular blood transfusion. Using this drug may mean that the person can have fewer blood transfusions.
There is a small risk of infection from blood transfusions, with concern surrounding the spread of HIV and hepatitis in particular. However, it is not common to get these infections from blood transfusions, and the benefits outweigh this particular risk.
Blood transfusions can lead to excess iron in the body. This can affect how the liver, heart, and other organs function. However, this is usually seen in patients who have had a lot of transfusions over several years. Some medications can help keep iron levels under control, and people with excess iron are advised not to take iron supplements or vitamins that contain iron.
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Increasing low platelet counts
Platelet transfusions can help to increase the level of platelets in the blood to help a person who bleeds or bruises easily because of MDS.
Growth factor medications can be used to help raise the platelet counts if transfusions do not help, and if problems with bleeding are not improved, antifibrinolytic agents can be used.
Increasing low white blood cell counts
Infections are more likely to become serious if a person has a low white blood cell count. As such, people with low levels of white blood cells should be careful not to cut or damage their skin and keep any wounds clean as soon as they occur. Medical advice should be found if signs of an infection, such as a fever, shortness of breath, or urinary tract infections, develop.
Antibiotics, or white blood cell growth factors for serious infections, can be used to increase the white blood cell counts to fight the infection.
Chemotherapy
Chemotherapy is the name for treatment that uses drugs often used to treat cancer. Chemotherapy aims to kill the abnormal stem cells growing in the bone marrow so that new, healthy cells can grow. This type of treatment is called a systemic treatment because it reaches most areas of the body through the bloodstream.
The types of chemotherapy used in treating MDS include:
Hypomethylating agents
This type of chemotherapy drug activates genes inside cells that encourage cells to mature. Hypomethylating agents also kill cells that divide quickly.
This treatment can improve red blood cell counts and a person may not need transfusions if the hypomethylating agent improves the blood cell count enough.
Standard chemotherapy medication
This range of chemotherapy medications are not as effective against MDS as hypomethylating agents are. As a result, they are not used often to treat MDS. However, in higher-risk MDS, acute myeloid leukemia (AML) is more likely to develop, so the same chemotherapy used to treat AML can be used to treat higher-risk MDS, too.
Immunotherapy
Immunomodulating drugs (IMiDs)
IMiDs are most effective in people who have MDS cells that are missing a part of chromosome 5 (MDS-del(5q)). However, patients who do not have this chromosome section missing can also benefit from immunomodulating drugs. They can stop the need for blood transfusions for a short period in low-grade MDS.
Immune system suppressants
An antibody called anti-thymocyte globulin (ATG) works against white blood cells called T-lymphocytes, which help control how the immune system reacts. These cells can interrupt the normal production of blood cells, so ATG can help regulate this process. Another immune system suppressant that can be used in conjunction with ATG is cyclosporine.
This type of treatment is most effective in people with low cell numbers in the bone marrow.
Stem Cell Transplants
Stem cell transplants along with high-dose chemotherapy are the only treatment that can cause long-term remission. Stem cell transplants may not be suitable for older people or those who have other medical conditions.
In this treatment, the bone marrow that contains abnormal cells is replaced by hematopoietic stem cells, which develop into healthy bone marrow that creates normal blood cells. There are two types of stem cell transplants: allogeneic transplants and autologous transplants. Allogeneic transplants use donated stem cells from another person. Autologous transplants use the person’s own stem cells for the transplant.
A person undergoing this treatment will have their stem cells harvested from the bone marrow. The stem cells will be frozen while the person has chemotherapy or radiotherapy treatment, and then they will be given back their own stem cells or stem cells from a separate donor. Allogenic transplants are usually recommended for people living with MDS.
Summary
There are many approaches to treating myelodysplastic syndromes. The type of treatment a person will receive depends on their age, their overall health, and the type of MDS they have, along with their IPSS score.
Chemotherapy, immunotherapy, symptom management, and stem cell transplantation are the main types of treatment used for myelodysplastic syndromes.
Further Reading