Summary

Key Points

• Myeloproliferative neoplasms are a group of diseases in which the bone marrow makes too many red blood cells, white blood cells, or platelets.
• There are 6 types of chronic myeloproliferative neoplasms.
• Tests that examine the blood and bone marrow are used to detect (find) and diagnose chronic myeloproliferative neoplasms.

Myeloproliferative neoplasms 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 become mature blood cells over time.

A blood stem cell may become a myeloid stem cell or a lymphoid stem cell. A lymphoid stem cell becomes a white blood cell. A myeloid stem cell becomes one of three types of mature blood cells:

• Red blood cells that carry oxygen and other substances to all tissues of the body.
• White blood cells that fight infection and disease.
• Platelets that form blood clots to stop bleeding.

In myeloproliferative neoplasms, too many blood stem cells become one or more types of blood cells. The neoplasms usually get worse slowly as the number of extra blood cells increases.

There are 6 types of chronic myeloproliferative neoplasms.

The type of myeloproliferative neoplasm 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 neoplasms include the following 6 types:

• Chronic myelogenous leukemia.
• Polycythemia vera.
• Primary myelofibrosis (also called chronic idiopathic myelofibrosis).
• Essential thrombocythemia.
• Chronic neutrophilic leukemia.
• Chronic eosinophilic leukemia.

These types are described below. Chronic myeloproliferative neoplasms sometimes become acute leukemia, in which too many abnormal white blood cells are made.

Screening and Detection

Tests that examine the blood and bone marrow are used to detect (find) and diagnose chronic myeloproliferative neoplasms.

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.
• Peripheral blood smear: A procedure in which a sample of blood is checked for the following:
  • Whether there are red blood cells shaped like teardrops.
  • The number and kinds of white blood cells.
  • The number of platelets.
  • Whether there are blast cells.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease.
• Bone marrow aspiration and biopsy: The removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologist views the bone marrow, blood, and bone under a microscope to look for abnormal 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. Certain diseases or disorders may be diagnosed or ruled out based on the chromosomal changes.
• Gene mutation test: A laboratory test done on a bone marrow or blood sample to check for mutations in JAK2, MPL, or CALR genes. A JAK2 gene mutation is often found in patients with polycythemia vera, essential thrombocythemia, or primary myelofibrosis. MPL or CALR gene mutations are found in patients with essential thrombocythemia or primary myelofibrosis.

Treatment Options

There are different types of treatment for patients with chronic myeloproliferative neoplasms.

Different types of treatments are available for patients with chronic myeloproliferative neoplasms. 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.

Eleven types of standard treatment are used:

Watchful waiting

Watchful waiting is closely monitoring a patient’s condition without giving any treatment until signs or 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 neoplasms.

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 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 Neoplasms for more information.

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 neoplasms is usually directed at the spleen.

Other drug therapy

Prednisone and danazol are drugs that may be used to treat anemia in patients with primary myelofibrosis.

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, lenalidomide, and pomalidomide are drugs that prevent blood vessels from growing into areas of tumor cells.

See Drugs Approved for Myeloproliferative Neoplasms for more information.

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 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 neoplasms.

Erythropoietic growth factors are also biologic agents. They are used to stimulate the bone marrow to make red blood cells.

Targeted therapy

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.

Ruxolitinib is a tyrosine kinase inhibitor used to treat certain types of myelofibrosis.

See Drugs Approved for Myeloproliferative Neoplasms for more information.

Other types of targeted therapies are being studied in clinical trials.

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.

New types of treatment are being tested in clinical trials.

Information about clinical trials is available from the NCI website.

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.

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.