Myelodysplastic syndromes (MDS) are a rare group of bone marrow disorders. In MDS, the body does not make enough healthy blood cells for the bone marrow. Bone marrow contains parent cells called stem cells. Stem cells can rapidly divide and clone themselves to form new cells. In MDS, some stem cells are abnormal. Abnormal cells may not develop into normal cells. Instead, abnormal, immature cells crowd out normal cells in the bone marrow. This abnormal cell development does not allow the bone marrow to make the healthy cells needed for the body. The abnormal cells can build up and overcrowd the bone marrow. As a result, your body may not make enough red blood cells, white blood cells, or platelets. MDS may get worse over time. In some cases, it may develop to a fast-growing cancer called acute myeloid leukemia (AML). About 1 out of 3 with MDS, who have other risk factors, may develop AML.
Symptoms of MDS
MDS causes low levels of one or more types of blood cells (anemia, leukopenia, thrombocytopenia). This is called cytopenia. MDS is often slow-growing, and people may have no early symptoms of the disease. Symptoms of MDS differ depending on the cell type affected as below.
Anemia describes a low number of healthy red blood cells. Red blood cells carry oxygen through the body. Anemia is often the first symptom recognized in a person with MDS. Early on, a person may have mild symptoms or none at all. As the red cell count drops, and the anemia worsens, more symptoms may develop. You may experience the following if you have a low red blood cell count:
- Feel sleepy or tired
- Loss of appetite
- Pale skin
- Chest pain
- Shortness of breath
- Irregular or rapid heartbeats
- Cold hands and feet
Leukopenia is caused by a drop in any white blood cells. Usually presents with neutropenia. A low number of white blood cells means there are fewer disease-fighting cells (leukocytes) in your blood. You may experience the following if you have a low white blood cell count:
- Inflammation in and around the mouth
- Frequent infections or infections that don’t go away
Neutropenia (a type of leukopenia) refers to a decrease in neutrophils, the most common type of white blood cell. A low number of white blood cells can lead to frequent or severe infections.
- Lung infections that cause coughing and difficulty breathing
- Mouth sores
- Sinus infections
- Skin infections
- Bladder infections that are painful or make you urinate more often
Thrombocytopenia occurs when you have a low number of healthy platelets. Platelets help control bleeding (form clots). This condition can range from mild to severe. In rare cases, the number of platelets drops so low that internal bleeding occurs. Bleeding that will not stop is considered a medical emergency. If you have a low platelet count, you may experience:
- Unexplained bruising or bleeding
- Nose bleeds
- Bleeding gums, especially after brushing your teeth
- Tiny, flat red spots under your skin (petechiae)
- Heavier than normal menstrual periods (for women)
Types of MDS
MDS is broken up into groups based on features of the bone marrow and blood cells. These groups are called subtypes. The World Health Organization (WHO) separates MDS into groups based on how the cells within the bone marrow look under a microscope. Based on factors, the WHO system recognizes 6 types of MDS. You can find below main types of MDS
MDS with ring sideroblasts
MDS with ring sideroblasts (MDS-RS) is described as when a person has many red blood cells containing rings of iron deposits (ring sideroblasts). It most often affects older people or people of late middle age. There is an increased risk of developing leukemia with this type of MDS. This condition is further divided into 2 types (MDS-RS-SLD or MDS-RS-MLD), based on how many of the cell types in the bone marrow are affected by dysplasia. Dysplasia describes abnormal appearance of cells within a tissue or organ. MDS with multilineage dysplasia An individual with MDS with multilineage dysplasia (MDS-MLD) has 1 or more cytopenias (one or more blood cell types are lower than they should be) and dysplastic changes in 2 or more of the myeloid lineage (erythroid, granulocytic, and megakaryocytic).
MDS with excess blasts
A person with MDS with excess blasts (immature blood cells) has more blasts than normal in the bone marrow, and at least 1 cell type with lower than normal numbers. There may or may not be severe dysplasia in the bone marrow. This type of MDS is broken up into two types based on the number of excess blasts (MDS- RAEB type 1 and 2). It accounts for about 1 in 4 cases. It is one of the types of MDS most likely to turn into acute myeloid leukemia (AML), with the risk being higher for MDS-EB2 than for MDS-EB1. Blast count 5-10 % is RAEB type 1 and Blast count 10-20 % is RAEB type 2.
MDS with isolated del(5q)
Someone with MDS with isolated del(5q) has one abnormal chromosome change in their cells in the bone marrow. This change is called del(5q), which means that part of chromosome 5 is missing (deleted). In some circumstances, one additional abnormal chromosome may be present. Less than 5 percent of cells in the bone marrow are blast cells. This type of MDS is most often found among middle-aged or older women and treatment of that type is lenalidomide treatment.
Erythroid maturation agent
An erythroid maturation agent (EMA) is used to treat anemia.
For low risk MDS patients if the serum erythropoietin level less than 500 epoetin alfa or darbepoetin alfa are given in increasing red blood cell production.
Luspatercept is an erythroid (red blood cell) maturation agent used when erythropoiesis-stimulating agents (ESAs) such as epoetin alfa and darbepoetin alfa are not effective in increasing red blood cell production. Luspatercept is specifically used in adults with very low- to intermediate- risk myelodysplastic syndromes with ring sideroblasts (MDS-RS) or with myelodysplastic/ myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN- RS-T).
Immunosuppressive therapy supports the body’s natural defenses to fight MDS. It uses materials made either by the body or in a laboratory to improve, target, or restore immune system function. Immunosuppressive therapy is a type of drug therapy that lowers the body’s immune response to allow bone marrow stem cells to grow and make new blood cells.
Lenalidomide (Revlimid®) is a drug used to increase hemoglobin levels (the protein in red blood cells that carry oxygen). Lenalidomide is used to treat MDS with cells that are missing part of chromosome 5. This is referred to as “del(5q).” Lenalidomide may reduce or prolong the need for a transfusion for people with MDS with del(5q), as well as those with lower-risk
Chemotherapy is used to treat REAB 1 and RAEB type 2. Chemotherapies used to treat MDS:
- Azacitidine (Vidaza)
- Decitabine (Dacogen)
These drugs are a type of chemotherapy called hypomethylating agents. They work by blocking deoxyribonucleic acid (DNA) that helps abnormal cells grow. This helps to “turn on” genes that promote the growth of normal, healthy cells in the bone marrow.
Bone marrow transplant (BMT)
Bone marrow transplant is done following azacytidine and decitabine treatment for RAEB type 1 and REAB type 2 patients. RAEB Type 1 patients can go directly to BMT without treatment.
Bone marrow transplant (BMT), also called stem cell transplant, is a type of treatment that destroys cells in the bone marrow then replaces them with new, healthy blood-forming cells from another person. These blood-forming cells are called blood stem cells. Bone marrow is the soft, spongy area in the center of some of the larger bones in your body. The marrow produces all of the different cells that make up the blood, such as red blood cells, white blood cells (of many different types), and platelets. All of the cells of the immune system are also made in the bone marrow. The goal of an BMT is to cure cancer by replacing unhealthy blood stem cells with healthy ones. The transplanted healthy cells may also recognize and attack cancer cells. This is done by first suppressing the normal stem cells and cancer cells with chemotherapy. Then, healthy stem cells from another person are infused. The healthy stem cells will expand to form new cells, and potentially attack any remaining cancer cells.For the treatment of MDS, blood stem cells from a donor are used for the transplant. This is called an allogeneic BMT. Before the transplant, special testing must be done to make sure the donor is a good match for you. Before transplanting stem cells, the patient will have conditioning treatment (chemotherapy), the blood stem cells will be put into your body with a transfusion. The transplanted blood stem cells will naturally travel to your bone marrow where they may expand and grow. The transplanted cells will make new, healthy blood cells. This process is called engraftment. It usually takes about 2 to 4 weeks for the transplanted stem cells to establish in the bone marrow and begin to make mature blood cells. During this period, you will be in the hospital. You will also be at higher risk for infection and bleeding. It may take weeks or months for blood cells to fully recover and your immune system to go back to normal.