Myeloproliferative disorders are a group of diseases in which the bone marrow produces too many red blood cells, white blood cells, or platelets.

Normally, the bone marrow makes stem cells (immature blood cells) that develop into mature blood cells. There are 3 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.
  • Platelets that help prevent bleeding by causing blood clots to form.

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:

  • Chronic myelogenous leukemia.
  • Polycythemia vera.
  • Chronic idiopathic myelofibrosis.
  • Essential thrombocythemia.
  • Chronic neutrophilic leukemia.
  • Chronic eosinophilic leukemia.

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:

  • 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: 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.
  • 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 the bone marrow samples under a microscope to look for signs of cancer.
  • 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. Certain diseases or disorders may be diagnosed or ruled out based on the chromosomal changes.

Polycythemia Vera

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 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:

  • A feeling of pressure or fullness below the ribs on the left side.
  • Headaches.
  • Double vision or seeing dark or blind spots that come and go.
  • Itching all over the body, especially after being in warm or hot water.
  • Reddened face that looks like a blush or sunburn.
  • Weakness.
  • Dizziness.
  • Weight loss for no known reason.

Special blood tests are used to diagnose polycythemia vera.

In addition to a complete blood count, other special blood tests are used to diagnose polycythemia vera. These tests include the following:

  • Arterial blood gas (ABG) test: A test in which a sample of blood is taken from an artery to measure the amount of oxygen and carbon dioxide in the blood and the pH (acidity) of the blood.
  • Serum erythropoietin test: A test in which a sample of blood is checked for the level of erythropoietin (a hormone that stimulates new red blood cells to be made).
  • Leukocyte alkaline phosphatase (LAP) test: A test in which a sample of blood is checked to measure the amount of alkaline phosphatase (an enzyme) in leukocytes (white blood cells).

Chronic Idiopathic Myelofibrosis

Chronic idiopathic 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 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:

  • Feeling pain or fullness below the ribs on the left side.
  • Feeling full sooner than normal when eating.
  • Feeling very tired.
  • Shortness of breath.
  • Easy bruising or bleeding.
  • Petechiae (flat, red, pinpoint spots under the skin that are caused by bleeding).
  • Fever.
  • Night sweats.
  • Weight loss.

A special blood test is used to diagnose chronic idiopathic myelofibrosis.

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:

  • The age of the patient.
  • The number of abnormal red blood cells and white blood cells.
  • The number of blasts in the blood.
  • Whether there are certain changes in the chromosomes.
  • Whether the patient has symptoms such as fever, night sweats, or weight loss.

Essential Thrombocythemia

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:

  • Headache.
  • Burning or tingling in the hands or feet.
  • Redness and warmth of the hands or feet.
  • Vision or hearing problems.

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:

  • The age of the patient.
  • Whether the patient has symptoms or other problems related to essential thrombocythemia.

Chronic Neutrophilic Leukemia

 

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.

Chronic Eosinophilic 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:

  • Fever.
  • Feeling very tired.
  • Cough.
  • Swelling under the skin around the eyes and lips, in the throat, or on the hands and feet.
  • Muscle pain.
  • Itching.
  • Diarrhea.

Stages of 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

Treatment Option Overview

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. 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.

Ten types of standard treatment are used:

Watchful waiting

Watchful waiting is closely monitoring a patient’s condition without giving any treatment until symptoms appear or change.

Phlebotomy

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

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

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

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 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 therapy

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. Thalidomide is a drug that prevents blood vessels from growing into areas of tumor cells.

Surgery

Splenectomy (surgery to remove the spleen) may be done if the spleen is enlarged.

Biologic therapy

Biologic 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 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.

Polycythemia Vera

The purpose of treatment for polycythemia vera is to reduce the number of extra blood cells. Treatment of polycythemia vera may include the following:

  • Phlebotomy.
  • Chemotherapy with or without phlebotomy.
  • Biologic therapy using interferon alfa.
  • A clinical trial of a new treatment.

Chronic Idiopathic Myelofibrosis

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:

  • Transfusion of red blood cells to relieve symptoms and improve quality of life.
  • Biologic therapy using interferon alfa.
  • Splenectomy.
  • Radiation therapy to the spleen.
  • Chemotherapy.
  • Donor stem cell transplant.
  • Thalidomide.

Essential Thrombocythemia

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:

  • Chemotherapy.
  • Anagrelide therapy.
  • Biologic therapy using interferon alfa.
  • Platelet apheresis.
  • A clinical trial of a new treatment.

Chronic Neutrophilic Leukemia

Treatment of chronic neutrophilic leukemia may include the following:

  • Donor bone marrow transplant.
  • Chemotherapy.
  • Biologic therapy using interferon alfa.
  • A clinical trial of a new treatment.

Chronic Eosinophilic Leukemia

Treatment of chronic eosinophilic leukemia may include the following:

  • Bone marrow transplant.
  • Biologic therapy using interferon alfa.
  • A clinical trial of a new treatment.

 

Source: National Cancer Institute