What is MDS?

Myelodysplastic syndromes (MDS) are conditions that can occur when the blood-forming cells in the bone marrow become abnormal. This leads to low numbers of one or more types of blood cells. MDS is considered a type of cancer.

Normal bone marrow

Bone marrow is found in the middle of certain bones. It is made up of blood-forming cells, fat cells, and supporting tissues. A small fraction of the blood-forming cells are blood stem cells. Stem cells are needed to make new blood cells.

There are 3 main types of blood cells: red blood cells, white blood cells, and platelets.

Red blood cells pick up oxygen in the lungs and carry it to the rest of the body. These cells also bring carbon dioxide back to the lungs. Having too few red blood cells is called anemia. It can make a person feel tired and weak and look pale. Severe anemia can cause shortness of breath.

White blood cells (also known as leukocytes) are important in defending the body against infection. There are different types of white blood cells:

  • Granulocytes are white blood cells that have granules that can be seen under the microscope. In the bone marrow, granulocytes develop from young cells called myeloblasts. The most common type of granulocyte is the neutrophil. When the number of neutrophils in the blood is low, the condition is called neutropenia. This can lead to severe infections.
  • Monocytes are also important in protecting the body against germs. The cells in the bone marrow that turn into monocytes are called monoblasts.
  • Lymphocytes make proteins called antibodies that help the body fight germs. They can also directly kill invading germs. Lymphocytes are not usually abnormal in MDS.

Platelets are thought of as a type of blood cell, but they are actually small pieces of a cell. They start as a large cell in the bone marrow called the megakaryocyte. Pieces of this cell break off and enter the bloodstream as platelets. You need platelets for your blood to clot. They plug up damaged areas of blood vessels caused by cuts or bruises. A shortage of platelets, called thrombocytopenia, can result in abnormal bleeding or bruising.

Myelodysplastic syndromes

In MDS, some of the cells in the bone marrow are abnormal (dysplastic) and have problems making new blood cells. Many of the blood cells formed by these bone marrow cells are defective. Defective cells often die earlier than normal cells, and the body also destroys some abnormal blood cells, leaving the person without enough normal blood cells. Different cell types can be affected, although the most common finding in MDS is a shortage of red blood cells (anemia).

There are several different types of MDS, based on how many types of blood cells are affected and other factors.

In about 1 in 3 patients, MDS can progress to a rapidly growing cancer of bone marrow cells called acute myeloid leukemia (AML). In the past, MDS was sometimes referred to as pre-leukemia or smoldering leukemia. Because most patients do not get leukemia, MDS used to be classified as a disease of low malignant potential. Now that doctors have learned more about MDS, it is considered to be a form of cancer.

WRITTEN BY: The American Cancer Society medical and editorial content team. See original article and references.

What are the Symptoms of MDS?

The main symptoms of MDS are a consequence of the low blood counts (cytopenias):

  • Fatigue, shortness of breath, palpitations (common anemia symptoms from low red blood cells)
  • Fever, recurrent or prolonged infections (common neutropenia symptoms from low white blood cells)
  • Bruising, petechiae, or bleeding (common thrombocytopenia symptoms from low platelet counts)

How is MDS diagnosed?

Routine complete blood counts (CBC) often indicate decreased levels of blood cells and prompt referral to a blood specialist (hematologist or oncologist). After excluding vitamin deficiencies (such as low iron or vitamin B12), a bone marrow evaluation is performed. This involves inserting a needle into the hip bone and removing a small specimen for examination under the microscope. A diagnosis of MDS requires abnormal changes (dysplasia) observed in at least one blood cell factory. The sample may also be examined for changes (mutations) of chromosomes or genes, which determine prognosis and may influence treatment decisions.

WRITTEN BY: The Myelodysplastic Syndromes Foundation, Inc. See original article and references.

General Approach to Treatment

The treatment approach for myelodysplastic syndromes (MDS) depends on a number of factors, such as:

  • The type of MDS
  • The prognostic score (risk group) of the MDS
  • A person’s age, overall health, and preferences

Some people with MDS who don’t have very low blood cell counts or bothersome symptoms might not need to be treated right away.

If treatment is needed, a stem cell transplant (SCT) is usually considered the only way to potentially cure MDS, so it may be the treatment of choice for younger, relatively healthy patients if a matched donor is available. Unfortunately, many people with MDS are older or in poor health and might not be good candidates for a SCT.

When SCT is not an option, MDS is very unlikely to be cured, but it can often still be treated. The main goal of treatment is to relieve symptoms and avoid complications and side effects.

If low blood counts are causing problems, supportive care treatments such as transfusions or blood cell growth factors may be helpful. Careful general medical care and measures to prevent and treat infections are also very important. Supportive care is important regardless of whether a person is getting other treatments for MDS.

If other treatment is needed, a chemotherapy drug such as azacitidine (Vidaza) or decitabine (Dacogen) is often the first choice, especially for patients with lower-risk forms of MDS. These drugs can often improve blood counts, and many patients need fewer transfusions and have a better quality of life, with less fatigue. These drugs can also help some people live longer. Another option for some people might be medicines to suppress the immune system, such as ATG and cyclosporine.

For some patients with more advanced MDS, such as those whose prognostic scores are high risk or higher, or those whose MDS looks like it is becoming acute myeloid leukemia (AML), standard chemotherapy drugs might be an option. Unfortunately, this treatment can often be too toxic for patients who are elderly or who have many other medical problems. For young and healthy patients, though, the treatment is similar to treatment for AML.

If one type of treatment doesn’t work (or if it stops working), another one might be tried. Many new medicines to treat MDS are also being studied in clinical trials. Because the best options to treat MDS aren’t clear, and because MDS often becomes hard to treat over time, taking part in a clinical trial might be a good option at some point. Talk to your health care team to learn more about clinical trials that might be right for you.

*The treatment information given here is not official policy of the American Cancer Society and is not intended as medical advice to replace the expertise and judgment of your cancer care team. It is intended to help you and your family make informed decisions, together with your doctor. Your doctor may have reasons for suggesting a treatment plan different from these general treatment options. Don’t hesitate to ask him or her questions about your treatment options.

WRITTEN BY: The American Cancer Society medical and editorial content team. See original article and references.