Last Modified : 2005-07-19
Normally, the bone marrow makes stem cells (immature blood cells) that develop into mature blood cells. There are 3 types of mature blood cells:
Myeloproliferative disorders begin in the bone marrow and may cause a greater than normal number of stem cells to develop into one or more types of blood cells. The disorders usually get worse slowly as the number of extra blood cells slowly 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. Refer to the PDQ summary on Chronic Myelogenous Leukemia Treatment for information on diagnosis, staging, and treatment.
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. In patients older than 65 years, the risk of stroke and heart attack is higher, and polycythemia vera is more likely to become acute myeloid leukemia or chronic idiopathic 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:
In addition to a complete blood count, other special blood tests are used to diagnose polycythemia vera. These tests include the following:
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 chronic idiopathic myelofibrosis, large numbers of bone marrow 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 chronic idiopathic myelofibrosis include pain below the ribs on the left side and feeling very tired.Chronic idiopathic myelofibrosis often does not cause early symptoms. It is sometimes found during a routine blood test. The following symptoms may be caused by chronic idiopathic myelofibrosis or by other conditions. A doctor should be consulted if any of these problems occur:
In addition to a complete blood count, bone marrow aspiration and biopsy, and cytogenetic analysis, a peripheral blood smear is used to diagnose chronic idiopathic 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 chronic idiopathic myelofibrosis.Prognosis (chance of recovery) depends on the following:
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 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.
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:
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.
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. Before starting treatment, patients may want to think about taking part in a clinical trial. 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.
Clinical trials are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site. Choosing the most appropriate treatment is a decision that ideally involves the patient, family, and health care team.
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.
PhlebotomyPhlebotomy 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 apheresisPlatelet 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 therapyTransfusion 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.
ChemotherapyChemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells 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 spinal column, 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.
Radiation therapyRadiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. 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 therapyAnagrelide therapy is used to reduce the risk of blood clots in patients who have too many platelets in their blood.
SurgerySplenectomy (surgery to remove the spleen) may be done if the spleen is enlarged.
Biologic therapyBiologic therapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy. Interferon alfa is a biologic agent commonly used to treat some chronic myeloproliferative disorders.
High-dose chemotherapy with stem cell transplantHigh-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.
New types of treatment are being tested in clinical trials.Information about ongoing clinical trials is available from the NCI Web site.
Refer to 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:
Information about ongoing clinical trials is available from the NCI Web site.
Treatment of chronic idiopathic myelofibrosis in patients without symptoms is usually watchful waiting.
Treatment of chronic idiopathic myelofibrosis in patients with symptoms may include the following:
This summary section refers to specific treatments under study in clinical trials, but it may not mention every new treatment being studied. Information about ongoing 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:
Information about ongoing clinical trials is available from the NCI Web site.
Treatment of chronic neutrophilic leukemia may include the following:
Information about ongoing clinical trials is available from the NCI Web site.
Treatment of chronic eosinophilic leukemia may include the following:
Information about ongoing clinical trials is available from the NCI Web site.