Myelodysplastic syndrome (MDS) refers to a group of blood and bone marrow cancers. It develops when a person has low levels of certain types of blood cell in their body.
Healthcare professionals used to call MDS "preleukemia," or "smoldering leukemia." However, as MDS only progresses to leukemia in around one-third of people, they now view it as being separate from leukemia.
It is unclear how many people receive a new diagnosis of MDS every year. Some organizations estimate the number to be around 10,000. Other estimates, however, are much higher.
In this article, we explore the symptoms and complications of MDS, as well as the causes and risk factors. We also give a brief overview of what to expect during diagnosis and treatment.
Bone marrow consists of soft tissue and fills the cavities of most bones. It is in this tissue that new blood cells form before moving into the bloodstream.
If not enough blood cells develop, or if they develop abnormally, the body may not have enough new blood cells. This can cause MDS.
Blood stem cells grow, then divide into one of three different types of blood cell:
- Red blood cells: These transport oxygen around the body.
- White blood cells: These protect the body from infection and respond to infectious organisms.
- Platelets: These promote wound healing and provide a clotting factor that helps stop bleeding.
If damage occurs to these cells, or if they reduce in number, it can harm a person's overall health.
The early stages of MDS may have no apparent symptoms. Later symptoms depend on which type of blood cell has experienced damage or is in short supply.
A blood test may reveal a reduced number of cells in the body. If the blood cell count for any one type is particularly low, a person may begin to experience some or all of the following symptoms.
Red blood cells
Having a lower amount of healthy red blood cells causes anemia. The signs of anemia often relate to a lack of oxygen reaching organs and cells around the body.
Symptoms range from mild to severe and may include:
- fatigue and a lack of energy
- pale skin
- heart palpitations
- shortness of breath
- chest pain
Anemia is a very common blood disorder that many factors can contribute to. Therefore, it may not be a direct symptom of MDS.
White blood cells
Frequent or unusually severe infections could signal damage to or shortage of white blood cells.
Medical professionals use the term "neutropenia" to describe a white blood cell count that is below the normal range.
"Thrombocytopenia" describes a low level of platelets. There are two main symptoms:
- bruising and bleeding more easily or more than usual
- small, dark red pinpoint spots that develop due to blood entering the skin
This could mean that a person has more nosebleeds than usual, develops bruising after minor injuries, or experiences bleeding gums.
Infection and bleeding pose a risk to people with MDS. People who have the condition should try to minimize injuries that could cause bruising or bleeding.
Dental work can often cause bleeding gums. A person who has MDS should seek advice before attending a dental appointment.
Sometimes, MDS progresses to acute myeloid leukemia (AML), a cancer of the blood cells. After diagnosing MDS, a doctor will assess the risk of progression to AML.
The exact reason that some people develop MDS but others do not remains unknown.
That said, some research into blood DNA has shown a link between genetic changes and blood disorders.
Specific genes contain information about how cells should grow and divide, and mutations in these genes can send the wrong information to cells. This means that they develop abnormally.
Several risk factors make it more likely that a person will develop MDS. That said, having one of these risk factors does not mean that they definitely will develop it.
The American Cancer Society suggest that risk factors for MDS include:
- previous treatment with chemotherapy or radiation therapy
- exposure to certain chemicals, such as pesticides, tobacco smoke, or benzene
- exposure to heavy metals, such as mercury or lead
- having undergone stem cell or bone marrow transplants
- age, as most cases of MDS occur in people over 50 years old
The differences between each blood disorder that a doctor classifies as MDS will depend on which of the blood cells types it affects and any changes to bone marrow.
The National Cancer Institute recognize eight different blood disorders as part of MDS. Doctors can carry out specific testing to identify which is present.
During testing for MDS, a person can expect some or all of the following:
- questions about medical history, including symptoms, illnesses, injuries, and any current medications
- a physical examination to check for signs of MDS, such as infection, bruising, or pain
- blood tests to assess the health and number of blood cells
- a bone marrow biopsy and aspiration, during which a doctor will remove a small amount of bone and bone marrow under anesthesia for testing
- genetic tests to check for any anomalies or mutations in the genes
At present, there is no cure for MDS. However, research continues to explore possible new treatments.
Treatment will be different for each person. It is likely to include supportive care that helps relieve the symptoms and regular infections that tend to accompany MDS. This may include a blood transfusion or antibiotics.
A doctor may also suggest one or more of the following treatment options:
- chemotherapy, which consists of the intravenous administration of medications to kill cancerous blood cells
- immunotherapy, in which a doctor infuses medications that trigger the immune system to respond to myelodysplastic cells
- a hematopoietic cell transplant, which replaces damaged or mutated stem cells with healthy ones
These treatment options have some side effects. For example, chemotherapy might lead to nausea and vomiting, while immunotherapy can cause fatigue and fever. Side effects will depend on the type of treatment and will vary from person to person.
People could take the following steps to improve their quality of life during treatment:
- follow a balanced, healthful diet
- exercise as often as possible
- seek support from friends and family members
- engage in mindful relaxation
The outlook will vary depending on the type and severity of MDS. Doctors use a range of scoring systems to determine the best treatment option and gauge its potential effectiveness.
A person's outlook also depends on whether or not MDS progresses to AML.
If a person is concerned about regular or severe infections, excessive bruising and bleeding, or other symptoms that could indicate MDS, they should see a doctor.
Learn more about the outlook for MDS, as well as the different scoring systems, here.
Can MDS ever spread to an organ, or does it always become leukemia when it progresses?
MDS does not spread to organs like other cancers, but the abnormal blood cell counts can affect certain organs.
MDS progresses to AML in one-third of cases, and certain types are more likely to progress than others.Yamini Ranchod, PhD, MS Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.