Myelodysplastic/Myeloproliferative Diseases

Myelodysplastic syndromes (MDS) and myeloproliferative disorders are diseases of the blood and bone marrow. The National Cancer Institute (NCI) says myelodysplastic syndromes are the result of not enough healthy blood cells being produced. Myeloproliferative disorders are the result of too many blood cells being produced.

Below, you'll find information on both diseases.

Myelodysplastic Syndromes (MDS)

The American Cancer Society (ACS) estimates that each year 10 to 15 thousand people are diagnosed with MDS. Most of them are over 60 years of age and more men than women are affected. MDS has not always been considered a cancer, according to ACS but is now being considered a form of cancer. ACS also says about 30 percent of MDS cases progress to become acute myeloid leukemia. (Read about "Leukemia")

NCI says basically the bone marrow does not make enough healthy blood cells. The key word there is healthy. Many of the cells that are created are abnormal. Normally, the bone marrow produces stem cells (immature cells) that develop into mature blood cells. There are three types of mature blood cells:

• Red blood cells that carry oxygen and other materials to all tissues of the body
• White blood cells that fight infection and disease (Read about "The Immune System")
• Platelets that help prevent bleeding by causing blood clots to form

In myelodysplastic syndromes, the stem cells do not mature into healthy red blood cells, white blood cells or platelets. The immature blood cells, called blasts, do not function normally and either die in the bone marrow or soon after they enter the blood. This leaves less room for healthy white blood cells, red blood cells and platelets to develop in the bone marrow. When there are fewer blood cells, infection, anemia (Read about "Anemia"), or easy bleeding may occur.

There are several types of myelodysplastic syndromes. Myelodysplastic syndromes include the following diseases, according to NCI:

• Refractory anemia: There are too few red blood cells in the blood and the patient has anemia. The number of white blood cells and platelets is normal. ACS says between 5 and 10 percent of MDS patients have refractory anemia and that it seldom progresses to acute myeloid leukemia.
• Refractory anemia with ringed sideroblasts: There are too few red blood cells in the blood and the patient has anemia. The red blood cells have too much iron. The number of white blood cells and platelets is normal. ACS says 10 to 15 percent of MDS patients have this type and it seldom becomes leukemia.
• Refractory anemia with excess blasts: There are too few red blood cells in the blood and the patient has anemia. Five percent to 19 percent of the cells in the bone marrow are blasts and there are a normal number of blasts found in the blood. There also may be changes to the white blood cells and platelets. Refractory anemia with excess blasts may progress to acute myeloid leukemia. Some 40 percent of MDS patients have this, according to ACS.
• Refractory anemia with excess blasts in transformation: There are too few red blood cells, white blood cells and platelets in the blood and the patient has anemia. Twenty percent to 30 percent of the cells in the bone marrow are blasts and more than 5 percent of the cells in the blood are blasts. Refractory anemia with excess blasts in transformation is sometimes called acute myeloid leukemia, according to NCI.
• Refractory cytopenia with multilineage dysplasia: There are too few of at least two types of blood cells. Less than 5 percent of the cells in the bone marrow are blasts and less than 1 percent of the cells in the blood are blasts. If red blood cells are affected, they may have extra iron. Refractory cytopenia may progress to acute leukemia. Ten to 15 percent of MDS patients have this type and about 10 percent of them will develop leukemia, according to ACS.
• Myelodysplastic syndrome associated with an isolated del(5q) chromosome abnormality: There are too few red blood cells in the blood and the patient has anemia. Less than 5 percent of the cells in the bone marrow and blood are blasts. There is a specific change in the chromosome. ACS says this rarely results in leukemia. (Read about "Genetics")
• Unclassifiable myelodysplastic syndrome: There are too few of one type of blood cell in the blood. The number of blasts in the bone marrow and blood is normal, and the disease is not one of the other myelodysplastic syndromes. This is uncommon, according to ACS and progression to leukemia seldom happens.

Age and past treatment with chemotherapy or radiation therapy affect the risk of developing a myelodysplastic syndrome. (Read about "Radiation Therapy") Other risk factors, according to NCI include the following: being older than 60 years and being exposed to certain chemicals, including tobacco smoke, pesticides and solvents such as benzene.

Myelodysplastic syndromes often do not cause early symptoms and are sometimes found during a routine blood test. (Read about "Laboratory Testing") Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• shortness of breath
• weakness or feeling tired
• having skin that is paler than usual
• easy bruising or bleeding
• petechiae (flat, pinpoint spots under the skin caused by bleeding)
• fever or frequent infections

Tests that examine the blood and bone marrow are used to detect and diagnose myelodysplastic syndromes. NCI says the following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
• Complete blood count (CBC) with differential: (Read about "Complete Blood Count") A procedure in which a sample of blood is drawn and checked for the following:
  • the number of red blood cells and platelets
  • the number and type of white blood cells
  • the amount of hemoglobin (the protein that carries oxygen) in the red blood cells
  • the portion of the blood sample made up of red blood cells
• Peripheral blood smear: A procedure in which a sample of blood is checked for changes in the number, type, shape and size of blood cells and for too much iron in the red blood cells.
• Cytogenetic analysis: A test in which cells in a sample of blood or bone marrow are viewed under a microscope to look for certain changes in the chromosomes. (Read about "Genetics")
• Bone marrow aspiration and biopsy: The removal of a small piece of bone and bone marrow by inserting a needle into the hipbone or breastbone. A pathologist views both the bone and bone marrow samples under a microscope to look for abnormal cells. (Read about "Biopsy")

Myelodysplastic syndromes are diagnosed based on certain changes in the blood cells and bone marrow.

There are certain factors that affect your prognosis (chance of recovery) and treatment options. NCI says the prognosis depends on the following:

• Whether the myelodysplastic syndrome occurred after chemotherapy or radiation therapy for another disease.
• The number of blast cells in the bone marrow.
• Whether one or more types of blood cells are affected.
• Certain changes in the chromosomes.

Treatment options depend on a number of factors as well including the following, according to NCI:

• Whether the myelodysplastic syndrome occurred after chemotherapy or radiation therapy for another disease.
• Whether the myelodysplastic syndrome has progressed after being treated.
• The age and general health of the patient.

Myeloproliferative Disorders

There is also a set of conditions called myeloproliferative disorders. They are the result of too many blood cells being produced. The type of myeloproliferative disorder is based on whether too many red blood cells, white blood cells or platelets are being made, according to NCI. Sometimes the body will make too many of more than one type of blood cell, but usually one type of blood cell is affected more than the others are. NCI says chronic myeloproliferative disorders include the following:

• Chronic myelomonocytic leukemia (CMML): This is a slowly progressing type of myeloproliferative disorder. In CMML, there are too many bone marrow stem cells that develop into two types of white blood cells called myelocytes and monocytes. Some of these bone marrow stem cells never become mature white blood cells. These immature white blood cells, called blasts, are unable to do their usual work. Over time, the myelocytes, monocytes and blasts crowd out the red blood cells and platelets in the bone marrow. When this happens, infection, anemia or easy bleeding may occur. Getting older, being male and past exposure to radiation can increase your risk of CMML
• Juvenile myelomonocytic leukemia (JMML): This is a rare form of childhood leukemia in which cancer cells often spread into tissues such as the skin, lung and intestines. Children who have neurofibromatosis type 1 and males have an increased risk of developing juvenile myelomonocytic leukemia. (Read about "Neurofibromatosis")
• Atypical chronic myelogenous leukemia (aCML): This is a slowly progressing disease in which too many white blood cells (not lymphocytes) are made in the bone marrow.
• Polycythemia vera: In polycythemia vera, the blood becomes thickened with too many red blood cells. The number of white blood cells and platelets may also increase. These extra blood cells may collect in the spleen and cause it to swell. The increased number of red blood cells or platelets in the blood can cause bleeding problems and make clots form in blood vessels. This can cause serious health problems such as stroke or heart attack. (Read about "Stroke" "Heart Attack")
• Chronic idiopathic myelofibrosis: A progressive, chronic disease in which the bone marrow is replaced by fibrous tissue and blood is made in organs such as the liver and the spleen, instead of in the bone marrow. This disease is marked by an enlarged spleen and progressive anemia. Also called agnogenic myeloid metaplasia, primary myelofibrosis, myelosclerosis with myeloid metaplasia, and idiopathic myelofibrosis. (Read about "The Liver" "The Spleen")
• Essential thrombocythemia: There is an increased number of thrombocytes (platelets) in the blood, without a known cause. Also called essential thrombocytosis.
• Chronic neutrophilic leukemia: A disease in which too many stem cells develop into a type of white blood cell called neutrophils. Neutrophils are infection-fighting blood cells that surround and destroy dead cells and foreign substances - such as bacteria. (Read about "Microorganisms") The spleen and liver may swell because of the extra neutrophils. Chronic neutrophilic leukemia may stay the same or it may progress quickly to acute leukemia. (Read about "The Immune System")
• Chronic eosinophilic leukemia: a disease in which too many white blood cells (eosinophils) are made in the bone marrow. Eosinophils are white blood cells that react to allergens (substances that cause an allergic response) and help fight infections caused by certain parasites. In chronic eosinophilic leukemia, there are too many eosinophils in the blood, bone marrow, and other tissues. Chronic eosinophilic leukemia may stay the same for many years or it may progress quickly to acute leukemia. (Read about "Allergies")

Chronic myeloproliferative disorders sometimes become acute leukemia (Read about "Leukemia"), in which too many abnormal white blood cells are made.

Treatments will depend on the type of myeloproliferative disorder a person has and other issues. NCI says there are ten standard treatments currently being used for myeloproliferative disorders. They are:

• Watchful waiting - monitoring a patient's condition without giving any treatment until symptoms appear or change.
• Phlebotomy - blood is taken from the body to remove extra red blood cells.
• Platelet apheresis - uses a special machine to remove platelets from the blood.
• Transfusion therapy - a method of giving red blood cells, white blood cells or platelets to replace blood cells destroyed by disease or cancer treatment. (Read about "Cancer Treatments")
• Chemotherapy - uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing.
• Radiation therapy - uses high-energy x-rays or other types of radiation to kill cancer cells. (Read about "Radiation Therapy")
• Other drug therapy - used to reduce the risk of blood clots in patients who have too many platelets in their blood.
• Surgery - may be done if the spleen is enlarged.
• Biologic therapy - uses the patient's immune system to fight cancer. (Read about "The Immune System")
• High-dose chemotherapy with stem cell transplant - a method of giving high doses of chemotherapy and replacing blood-forming cells destroyed by the cancer treatment. (Read about "Transplants")

Other types of treatment are being tested in clinical trials. (Read about "Clinical Studies")

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For a list of individual types of cancer, see Cancer: What It Is

For information on chemotherapy, radiation and other cancer therapies see Cancer Treatments

Related Information:

    Blood Disorders Glossary