Myelodysplastic/myeloproliferative neoplasms have characteristics of both myelodysplastic syndromes and myeloproliferative neoplasms. Myelodysplastic syndromes (MDSs) are a group of diseases in which the bone marrow does not make enough healthy mature blood cells (red blood cells, white blood cells and platelets). In myeloproliferative neoplasms (MPNs), the body makes too many of, or overproduces, 1 or more types of blood cells.
A myelodysplastic/myeloproliferative neoplasm may develop into an acute myelogenous leukemia (AML).
The following are types of myelodysplastic/myeloproliferative neoplasms:
Chronic myelomonocytic leukemia
Chronic myelomonocytic leukemia (CMML) is a disease in which too many monocytes (a type of white blood cell) develop in the bone marrow. Some of the cells do not develop into mature white blood cells. The monocytes and immature blood cells (called blasts) crowd out the other cells in the bone marrow so there aren’t enough red blood cells and platelets.
CMML usually occurs in people older than 60 years of age. It is more common in men than in women.
About 20%–40% of people with CMML have changes to certain chromosomes. CMML is similar to chronic myelogenous leukemia (CML), but the blasts with CMML do not have the Philadelphia (Ph) chromosome or the BCR-ABL mutation that blasts with CML have.
Some people with CMML have changes, or mutations, to certain genes such as:
- PDGFR-B and TEL
- JAK2 (Janus kinase 2)
What causes most cases of CMML is unknown. Receiving high doses of radiation or certain chemotherapy drugs to treat cancer may raise the risk of developing CMML.
The World Health Organization (WHO) categorizes CMML into 2 subtypes based on the number of blasts in the blood and bone marrow.
- CMML 1 means that less than 5% of the cells in the blood and less than 10% of the cells in the bone marrow are blasts.
- CMML 2 means that 5%–19% of the cells in the blood and 10%–19% of the cells in the bone marrow are blasts.
Atypical chronic myelogenous leukemia
Atypical chronic myelogenous leukemia (aCML) is a rare disorder in which too many blood stem cells in the bone marrow develop into granulocytes (a type of white blood cell). Some of the granulocytes do not mature. The immature cells are called blasts. Gradually the blasts and granulocytes crowd out the healthy red blood cells and platelets in the bone marrow.
aCML is similar to chronic myelogenous leukemia (CML), but the blasts do not have the Philadelphia (Ph) chromosome or the BCR-ABL mutation that the blasts with CML have.
Many people with aCML have changes to some chromosomes, but none are specific abnormalities. The average age at diagnosis is between 60 and 70 years.
Myelodysplastic/myeloproliferative neoplasm, unclassifiable
Myelodysplastic/myeloproliferative neoplasm, unclassifiable (MDS/MPN-UC) is a very rare disorder in which too many stem cells in the bone marrow develop into blood cells (red blood cells, white blood cells or platelets). Some of the blood cells do not mature. The immature blood cells are called blasts. Gradually the blasts and abnormal cells (called MDS/MPN-UC cells) crowd out the healthy blood cells in the bone marrow.
Some people with MDS/MPN-UC have the JAK2 gene mutation, which is also seen in people with myeloproliferative neoplasms.
A myelodysplastic/myeloproliferative neoplasm may not cause any signs or symptoms in its early stages. Symptoms develop as more abnormal cells build up in the blood and bone marrow.
See your doctor if you have:
- frequent infections
- shortness of breath
- easy bruising or bleeding
- night sweats
- feeling of fullness or abdominal discomfort if the liver or spleen is enlarged
- weight loss
Diagnosing a myelodysplastic/myeloproliferative neoplasm usually begins with a trip to your family doctor or when a routine blood test suggests a problem with the blood. Your doctor will ask you about any symptoms you have and do a physical exam to check if your spleen or liver is enlarged. Based on this information, your doctor will order tests to check for myelodysplastic/myeloproliferative neoplasm or other health problems.
The following tests are used to rule out or diagnose a myelodysplastic/myeloproliferative neoplasm:
- complete blood count (CBC) to measure the number and quality of white blood cells, red blood cells and platelets
- blood chemistry tests to show how well certain organs are working
- bone marrow aspiration and biopsy to confirm whether or not you have a myelodysplastic/myeloproliferative neoplasm
- cytogenetic tests on a sample of blood or bone marrow cells to look for certain changes to chromosomes
- fluorescence in situ hybridization (FISH) to look for specific changes in chromosomes and some abnormalities that are too small for standard cytogenetic testing to find
Find out more about these tests and procedures.
Your healthcare team will create a treatment plan just for you. The goal of treatment for a myelodysplastic/myeloproliferative neoplasm is to relieve symptoms, slow or prevent progression of the disease and improve quality of life. You may be offered a combination of different treatments.
People with myelodysplastic/myeloproliferative neoplasms may be treated with different drugs. For more information on certain drugs, go to sources of drug information.
Chemotherapy uses anticancer, or cytotoxic, drugs to destroy cancer cells. The drugs used depend on the type of myelodysplastic/myeloproliferative neoplasm.
The most common chemotherapy drugs used to treat CMML are cytarabine (Cytosar, Ara-C), etoposide (Vepesid, VP-16) and hydroxyurea (Hydrea). Other chemotherapy drugs that may be used for CMML include topotecan (Hycamtin), idarubicin (Idamycin) and fludarabine (Fludara).
Hydroxyurea (Hydrea) is a chemotherapy drug that may be used to treat aCML.
Other drugs that may be used to treat a myelodysplastic/myeloproliferative neoplasm include 5-azacytidine (Vidaza) and decitabine (Dacogen). Ruxolitinib (Jakavi) may be given if there is a mutation in the JAK2 gene.
Targeted therapy uses drugs to target specific molecules (for example, proteins) on or inside cells. These molecules help send signals that tell cells to grow or divide. By targeting these molecules, the drugs stop the growth and spread of cancer cells while limiting harm to normal cells.
Imatinib (Gleevec) is a targeted therapy drug that may be used to treat some people with CMML or MDS/MPN-UC.
Supportive therapy is given to relieve symptoms and lessen the problems caused by abnormal blood cell counts or treatment for a myelodysplastic/myeloproliferative neoplasm.
Transfusions may be used to treat low red blood cell or platelet counts.
Antibiotics are given to prevent or treat infections.
Growth factors are substances that regulate the growth, division and survival of cells. They help return blood cell counts to normal. Filgrastim (Neupogen) is a type of granulocyte colony-stimulating factor (G-CSF). It may be used to help the bone marrow make white blood cells, which can lower the risk of infection.
Stem cell transplant
A stem cell transplant may be a treatment option for some people with CMML.
Follow-up after treatment is an important part of cancer care. Follow-up for myelodysplastic/myeloproliferative neoplasms is often shared among the cancer specialists (oncologists) or blood specialists (hematologists) and your family doctor. Your healthcare team will work with you to decide on follow-up care to meet your needs.
Don’t wait until your next scheduled appointment to report any new symptoms and symptoms that don’t go away.
Research at the Canadian Centre for Applied Research in Cancer Control led to a new standard in leukemia testing.
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