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Myeloproliferative disorders are a group of diseases in which the bone marrow makes too many red blood cells, white blood cells, or platelets.
Normally, the bone marrow makes blood stem cells (immature cells) that develop into mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell. The lymphoid stem cell develops into a white blood cell. The myeloid stem cell develops into one of three types of mature blood cells:
Blood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell.
In myeloproliferative disorders too many blood stem cells develop into one or more types of blood cells. The disorders usually get worse slowly as the number of extra blood cells increases.
There are 6 types of chronic myeloproliferative disorders.
The type of myeloproliferative disorder is based on whether too many red blood cells, white blood cells, or platelets are being made. 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. Chronic myeloproliferative disorders include the following 6 types:
These types are described below. Chronic myeloproliferative disorders sometimes become acute leukemia, in which too many abnormal white blood cells are made.
Tests that examine the blood and bone marrow are used to detect (find) and diagnose chronic myeloproliferative disorders.
The following tests and procedures may be used:
Chronic myelogenous leukemia is a disease in which too many white blood cells are made in the bone marrow. See the PDQ summary on Chronic Myelogenous Leukemia Treatment for information on diagnosis, staging, and treatment.
Polycythemia vera is a disease in which too many red blood cells are made in the bone marrow.
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 increase the risk of stroke or heart attack. In patients who are older than 65 years or who have a history of blood clots, the risk of stroke or heart attack is higher. Patients also have an increased risk of developing acute myeloid leukemia or primary myelofibrosis.
Possible signs of polycythemia vera include headaches and a feeling of fullness below the ribs on the left side.
Polycythemia vera often does not cause early symptoms. It is sometimes found during a routine blood test. Symptoms may occur as the number of blood cells increases. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:
Special blood tests are used to diagnose polycythemia vera.
In addition to a complete blood count, bone marrow aspiration and biopsy, and cytogenetic analysis, a serum erythropoietin test is used to diagnose polycythemia vera. In this test, a sample of blood is checked for the level of erythropoietin (a hormone that stimulates new red blood cells to be made).
Primary myelofibrosis is a disease in which abnormal blood cells and fibers build up inside the bone marrow.
The bone marrow is made of tissues that make blood cells (red blood cells, white blood cells, and platelets) and a web of fibers that support the blood-forming tissues. In primary myelofibrosis (also called chronic idiopathic myelofibrosis), large numbers of blood stem cells develop into blood cells that do not mature properly (blasts). The web of fibers inside the bone marrow also becomes very thick (like scar tissue) and slows the blood-forming tissue's ability to make blood cells. This causes the blood-forming tissues to make fewer and fewer blood cells. In order to make up for the low number of blood cells made in the bone marrow, the liver and spleen begin to make the blood cells.
Possible signs of primary myelofibrosis include pain below the ribs on the left side and feeling very tired.
Primary myelofibrosis often does not cause early symptoms. It is sometimes found during a routine blood test. The following symptoms may be caused by primary myelofibrosis or by other conditions. A doctor should be consulted if any of these problems occur:
A special blood test is used to diagnose primary myelofibrosis.
In addition to a complete blood count, bone marrow aspiration and biopsy, and cytogenetic analysis, a peripheral blood smear is used to diagnose primary myelofibrosis. A peripheral blood smear is a procedure in which a sample of blood is checked for tear drop-shaped red blood cells, the number and kinds of white blood cells, the number of platelets, and the presence of blast cells.
Certain factors affect prognosis (chance of recovery) and treatment options for primary myelofibrosis.
Prognosis (chance of recovery) depends on the following:
Essential thrombocythemia is a disease in which too many platelets are made in the bone marrow.
Essential thrombocythemia causes an abnormal increase in the number of platelets made in the blood and bone marrow.
Patients with essential thrombocythemia may have no symptoms.
Essential thrombocythemia often does not cause early symptoms. It is sometimes found during a routine blood test. The following symptoms may be caused by essential thrombocytopenia or by other conditions. A doctor should be consulted if any of these problems occur:
Platelets are sticky. When there are too many platelets, they may clump together and make it hard for the blood to flow. Clots may form in blood vessels and there may also be increased bleeding. These can cause serious health problems such as stroke or heart attack.
Certain factors affect prognosis (chance of recovery) and treatment options for essential thrombocythemia.
Prognosis (chance of recovery) and treatment options depend on the following:
Chronic neutrophilic leukemia is a disease in which too many blood 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). 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.
Chronic eosinophilic leukemia is 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.
Possible signs of chronic eosinophilic leukemia include fever and feeling very tired.
Chronic eosinophilic leukemia may not cause early symptoms. It is sometimes found during a routine blood test. The following symptoms may be caused by chronic eosinophilic leukemia or by other conditions. A doctor should be consulted if any of these problems occur:
There is no standard staging system for chronic myeloproliferative disorders.
Staging is the process used to find out how far the cancer has spread. There is no standard staging system for chronic myeloproliferative disorders. Treatment is based on the type of myeloproliferative disorder the patient has. It is important to know the type in order to plan treatment.
There are three ways that cancer spreads in the body.
When cancer cells spread outside the blood, a solid tumor may form. This process is called metastasis. The three ways that cancer cells spread in the body are:
The new (metastatic) tumor is the same type of cancer as the primary cancer. For example, if leukemia cells spread to the brain, the cancer cells in the brain are actually leukemia cells. The disease is metastatic leukemia, not brain cancer.
There are different types of treatment for patients with chronic myeloproliferative disorders.
Different types of treatments are available for patients with chronic myeloproliferative disorders. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Ten types of standard treatment are used:
Watchful waiting is closely monitoring a patient's condition without giving any treatment until symptoms appear or change.
Phlebotomy is a procedure in which blood is taken from a vein. A sample of blood may be taken for tests such as a CBC or blood chemistry. Sometimes phlebotomy is used as a treatment and blood is taken from the body to remove extra red blood cells. Phlebotomy is used in this way to treat some chronic myeloproliferative disorders.
Platelet apheresis is a treatment that uses a special machine to remove platelets from the blood. Blood is taken from the patient and put through a blood cell separator where the platelets are removed. The rest of the blood is then returned to the patient's bloodstream.
Transfusion therapy (blood transfusion) is a method of giving red blood cells, white blood cells, or platelets to replace blood cells destroyed by disease or cancer treatment.
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.
See Drugs Approved for Myeloproliferative Disorders for more information.
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
Radiation therapy to treat myeloproliferative disorders is usually directed at the spleen.
Other drug therapy
Anagrelide therapy is used to reduce the risk of blood clots in patients who have too many platelets in their blood. Low-dose aspirin may also be used to reduce the risk of blood clots.
Thalidomide and lenalidomide are drugs that prevent blood vessels from growing into areas of tumor cells.
Splenectomy (surgery to remove the spleen) may be done if the spleen is enlarged.
Biologic therapy is a treatment that uses the patient's immune system to fight cancer or other diseases. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against disease. This type of treatment is also called biotherapy or immunotherapy. Interferon alfa and pegylated interferon alpha are biologic agents commonly used to treat some chronic myeloproliferative disorders.
Erythropoietic growth factors are also biologic agents. They are used to stimulate the bone marrow to make red blood cells.
High-dose chemotherapy with stem cell transplant
High-dose chemotherapy with stem cell transplant is a method of giving high doses of chemotherapy and replacing blood-forming cells destroyed by the cancer treatment. Stem cells (immature blood cells) are removed from the blood or bone marrow of the patient or a donor and are frozen and stored. After the chemotherapy is completed, the stored stem cells are thawed and given back to the patient through an infusion. These reinfused stem cells grow into (and restore) the body's blood cells.
Stem cell transplant (Step 1). Blood is taken from a vein in the arm of the donor. The patient or another person may be the donor. The blood flows through a machine that removes the stem cells. Then the blood is returned to the donor through a vein in the other arm.
Stem cell transplant (Step 2). The patient receives chemotherapy to kill blood-forming cells. The patient may receive radiation therapy (not shown).
Stem cell transplant (Step 3). The patient receives stem cells through a catheter placed into a blood vessel in the chest.
New types of treatment are being tested in clinical trials.
This summary section describes treatments that are being studied in clinical trials. It may not mention every new treatment being studied. Information about clinical trials is available from the NCI Web site.
Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells. Tyrosine kinase inhibitors are targeted therapy drugs that block signals needed for tumors to grow. JAK2 tyrosine kinase inhibitors are targeted therapy drugs being studied in clinical trials to treat primary myelofibrosis.
Patients may want to think about taking part in a clinical trial.
For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.
Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.
Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.
Patients can enter clinical trials before, during, or after starting their cancer treatment.
Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.
Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI's listing of clinical trials.
Follow-up tests may be needed.
Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests. This is sometimes called re-staging.
Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.
A link to a list of current clinical trials is included for each treatment section. For some types or stages of cancer, there may not be any trials listed. Check with your doctor for clinical trials that are not listed here but may be right for you.
Chronic Myelogenous Leukemia
See the PDQ summary on Chronic Myelogenous Leukemia Treatment for information.
The purpose of treatment for polycythemia vera is to reduce the number of extra blood cells. Treatment of polycythemia vera may include the following:
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with polycythemia vera. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.
Treatment of primary myelofibrosis in patients without symptoms is usually watchful waiting.
Treatment of primary myelofibrosis in patients with symptoms may include the following:
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with primary myelofibrosis. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.
Treatment of essential thrombocythemia in patients younger than 60 years who have no symptoms and an acceptable platelet count is usually watchful waiting. Treatment of other patients may include the following:
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with essential thrombocythemia. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.
Chronic Neutrophilic Leukemia
Treatment of chronic neutrophilic leukemia may include the following:
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with chronic neutrophilic leukemia. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.
Chronic Eosinophilic Leukemia
Treatment of chronic eosinophilic leukemia may include the following:
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with chronic eosinophilic leukemia. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.
For more information from the National Cancer Institute about chronic myeloproliferative disorders, see the following:
For general cancer information and other resources from the National Cancer Institute, see the following:
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Editorial changes were made to this summary.
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A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
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Last Revised: 2012-04-13
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