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Hairy Cell Leukemia Treatment (PDQ®)–Patient Version

General Information About Hairy Cell Leukemia

Key Points

  • Hairy cell leukemia is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell).
  • Leukemia may affect red blood cells, white blood cells, and platelets.
  • Signs and symptoms of hairy cell leukemia include infections, tiredness, and pain below the ribs.
  • Tests that examine the blood and bone marrow are used to diagnose hairy cell leukemia.
  • Certain factors affect treatment options and prognosis (chance of recovery).

Hairy cell leukemia is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell).

Hairy cell leukemia is a cancer of the blood and bone marrow. This rare type of leukemia gets worse slowly or does not get worse at all. The disease is called hairy cell leukemia because the leukemia cells look "hairy" when viewed under a microscope.

EnlargeAnatomy of the bone; drawing shows spongy bone, red marrow, and yellow marrow. A cross section of the bone shows compact bone and blood vessels in the bone marrow. Also shown are red blood cells, white blood cells, platelets, and a blood stem cell.
Anatomy of the bone. The bone is made up of compact bone, spongy bone, and bone marrow. Compact bone makes up the outer layer of the bone. Spongy bone is found mostly at the ends of bones and contains red marrow. Bone marrow is found in the center of most bones and has many blood vessels. There are two types of bone marrow: red and yellow. Red marrow contains blood stem cells that can become red blood cells, white blood cells, or platelets. Yellow marrow is made mostly of fat.

Leukemia may affect red blood cells, white blood cells, and 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 myeloid stem cell becomes one of three types of mature blood cells:

A lymphoid stem cell becomes a lymphoblast cell and then one of three types of lymphocytes (white blood cells):

EnlargeBlood cell development; drawing shows the steps a blood stem cell goes through to become a red blood cell, platelet, or white blood cell. A myeloid stem cell becomes a red blood cell, a platelet, or a myeloblast, which then becomes a granulocyte (the types of granulocytes are eosinophils, basophils, and neutrophils). A lymphoid stem cell becomes a lymphoblast and then becomes a B-lymphocyte, T-lymphocyte, or natural killer cell.
Blood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell.

In hairy cell leukemia, too many blood stem cells become lymphocytes. These lymphocytes are abnormal and do not become healthy white blood cells. The abnormal lymphocytes are also called leukemia cells. The leukemia cells can build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells, and platelets. This may cause infection, anemia, and easy bleeding. Some of the leukemia cells may collect in the spleen and cause it to swell.

Signs and symptoms of hairy cell leukemia include infections, tiredness, and pain below the ribs.

These and other signs and symptoms may be caused by hairy cell leukemia or by other conditions. Check with your doctor if you have any of the following:

  • Weakness or feeling tired.
  • Frequent infections.
  • Easy bruising or bleeding.
  • Shortness of breath.
  • Pain or a feeling of fullness below the ribs.
  • Painless lumps in the neck, underarm, stomach, or groin.

Tests that examine the blood and bone marrow are used to diagnose hairy cell leukemia.

In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform the following tests and procedures:

  • Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:
    • The number of red blood cells, white blood cells, and platelets.
    • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
    • The portion of the sample made up of red blood cells.
    EnlargeComplete blood count (CBC); left panel shows blood being drawn from a vein on the inside of the elbow using a tube attached to a syringe; right panel shows a laboratory test tube with blood cells separated into layers: plasma, white blood cells, platelets, and red blood cells.
    Complete blood count (CBC). Blood is collected by inserting a needle into a vein and allowing the blood to flow into a tube. The blood sample is sent to the laboratory and the red blood cells, white blood cells, and platelets are counted. The CBC is used to test for, diagnose, and monitor many different conditions.
  • Peripheral blood smear: A procedure in which a sample of blood is checked for cells that look "hairy," the number and kinds of white blood cells, the number of platelets, and changes in the shape of blood 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.
  • Flow cytometry: A laboratory test that measures the number of cells in a sample, the percentage of live cells in a sample, and certain characteristics of the cells, such as size, shape, and the presence of tumor (or other) markers on the cell surface. The cells from a sample of a patient’s blood, bone marrow, or other tissue are stained with a fluorescent dye, placed in a fluid, and then passed one at a time through a beam of light. The test results are based on how the cells that were stained with the fluorescent dye react to the beam of light. This test is used to help diagnose and manage certain types of cancers, such as leukemia and lymphoma.
  • 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 signs of cancer.
    EnlargeBone marrow aspiration and biopsy; drawing shows a patient lying face down on a table and a bone marrow needle being inserted into the hip bone. Inset shows the bone marrow needle being inserted through the skin into the bone marrow of the hip bone.
    Bone marrow aspiration and biopsy. After a small area of skin is numbed, a bone marrow needle is inserted into the patient’s hip bone. Samples of blood, bone, and bone marrow are removed for examination under a microscope.
  • Immunophenotyping: A laboratory test that uses antibodies to identify cancer cells based on the types of antigens or markers on the surface of the cells. This test is used to help diagnose specific types of leukemia.
  • Cytogenetic analysis: A laboratory test in which the chromosomes of cells in a sample of blood or bone marrow are counted and checked for any changes, such as broken, missing, rearranged, or extra chromosomes. Changes in certain chromosomes may be a sign of cancer. Cytogenetic analysis is used to help diagnose cancer, plan treatment, or find out how well treatment is working.
  • BRAF gene testing: A laboratory test in which a sample of blood or tissue is tested for certain changes in the BRAF gene. A BRAF gene mutation is often found in patients with hairy cell leukemia.
  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography. A CT scan of the abdomen may be done to check for swollen lymph nodes or a swollen spleen.

Certain factors affect treatment options and prognosis (chance of recovery).

The treatment options depend on the following:

  • The number of hairy (leukemia) cells and healthy blood cells in the blood and bone marrow.
  • Whether the spleen is swollen.
  • Whether there are signs or symptoms of leukemia, such as infection.
  • Whether the leukemia has recurred (come back) after previous treatment.

The prognosis depends on the following:

  • Whether the hairy cell leukemia does not grow or grows so slowly it does not need treatment.
  • Whether the hairy cell leukemia responds to treatment.

Treatment often results in a long-lasting remission (a period during which some or all of the signs and symptoms of the leukemia are gone). If the leukemia returns after it has been in remission, retreatment often causes another remission.

Stages of Hairy Cell Leukemia

Key Points

  • There is no standard staging system for hairy cell leukemia.
  • Sometimes hairy cell leukemia does not respond to treatment or comes back after treatment.

There is no standard staging system for hairy cell leukemia.

The process used to find out if cancer has spread to other parts of the body is called staging. There is no standard staging system for hairy cell leukemia.

In untreated hairy cell leukemia, some or all of the following conditions occur:

Sometimes hairy cell leukemia does not respond to treatment or comes back after treatment.

Refractory hairy cell leukemia is cancer that does not respond to treatment.

Recurrent hairy cell leukemia is cancer that has recurred (come back) after it has been treated.

Treatment Option Overview

Key Points

  • There are different types of treatment for patients with hairy cell leukemia.
  • The following types of treatment are used:
    • Watchful waiting
    • Chemotherapy
    • Immunotherapy
    • Targeted therapy
    • Surgery
  • New types of treatment are being tested in clinical trials.
  • Treatment for hairy cell leukemia may cause side effects.
  • Patients may want to think about taking part in a clinical trial.
  • Patients can enter clinical trials before, during, or after starting their cancer treatment.
  • Follow-up tests may be needed.

There are different types of treatment for patients with hairy cell leukemia.

Different types of treatment are available for patients with hairy cell leukemia. 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 for patients with cancer. 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.

The following types of 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.

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). The way the chemotherapy is given depends on the type and stage of the cancer being treated. Cladribine and pentostatin are anticancer drugs commonly used to treat hairy cell leukemia. These drugs may increase the risk of other types of cancer, especially Hodgkin lymphoma and non-Hodgkin lymphoma. Long-term follow up for second cancers is very important.

See Drugs Approved for Hairy Cell Leukemia for more information.

Immunotherapy

Immunotherapy 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.

See Drugs Approved for Hairy Cell Leukemia for more information.

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells.

  • Monoclonal antibody therapy: Monoclonal antibodies are immune system proteins made in the laboratory to treat many diseases, including cancer. As a cancer treatment, these antibodies can attach to a specific target on cancer cells or other cells that may help cancer cells grow. The antibodies are able to then kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells.

    Rituximab is a type of monoclonal antibody that may be used to treat certain patients with hairy cell leukemia.

    Moxetumomab pasudotox-tdfk is a monoclonal antibody linked to a toxin that may be used to treat hairy cell leukemia that has relapsed.

How do monoclonal antibodies work to treat cancer? This video shows how monoclonal antibodies, such as trastuzumab, pembrolizumab, and rituximab, block molecules cancer cells need to grow, flag cancer cells for destruction by the body’s immune system, or deliver harmful substances to cancer cells.

Other types of targeted therapies are being studied in the treatment of hairy cell leukemia, including:

  • Vemurafenib, a type of kinase inhibitor that blocks certain proteins made by the mutated BRAF gene, which may help keep cancer cells from growing.
  • Ibrutinib, a type of targeted therapy that blocks a protein called Bruton’s tyrosine kinase (BTK), which may help keep cancer cells from growing.

See Drugs Approved for Hairy Cell Leukemia for more information.

Surgery

Splenectomy is a surgical procedure to remove the spleen.

New types of treatment are being tested in clinical trials.

Information about clinical trials is available from the NCI website.

Treatment for hairy cell leukemia may cause side effects.

For information about side effects caused by treatment for cancer, see our Side Effects page.

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. Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.

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.

Treatment of Hairy Cell Leukemia

For information about the treatments listed below, see the Treatment Option Overview section.

Treatment of hairy cell leukemia may include the following:

You and your doctor will discuss what treatment plan is best for you.

Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.

To Learn More About Hairy Cell Leukemia

About This PDQ Summary

About PDQ

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

Purpose of This Summary

This PDQ cancer information summary has current information about the treatment of hairy cell leukemia. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Reviewers and Updates

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Updated") is the date of the most recent change.

The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Adult Treatment Editorial Board.

Clinical Trial Information

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.

Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).

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PDQ® Adult Treatment Editorial Board. PDQ Hairy Cell Leukemia Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/leukemia/patient/hairy-cell-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389248]

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