Hairy cell leukemia

What is hairy cell leukemia?

Hairy cell leukemia is a disease in which cancer (malignant) cells are found in the blood and bone marrow. The disease is called hairy cell leukemia because the cancer cells look "hairy" when examined under a microscope. Hairy cell leukemia affects white blood cells called lymphocytes . Lymphocytes are made in the bone marrow and other organs. The bone marrow is the spongy tissue inside the large bones in the body. The bone marrow makes:

• Red blood cells (which carry oxygen and other materials to all tissues of the body)
• White blood cells (which fight infection)
• Platelets (which make the blood clot)

Lymphocytes also are made in the spleen (an organ in the upper abdomen that makes lymphocytes and filters old blood cells from the blood), the lymph nodes (small bean-shaped organs throughout the body), and other organs.

When hairy cell leukemia develops, the leukemia cells may collect in the spleen. This causes the spleen to swell. There also may be too few normal white blood cells in the blood. This is because the leukemia cells invade the bone marrow, and the marrow cannot produce enough normal white blood cells. This may result in an infection.

A doctor should be seen if the following symptoms occur:

• Constant tiredness
• The spleen is larger than normal
• An infection won't go away

If there are symptoms, a doctor will order blood tests. The blood tests are used to count the number of each of the different types of blood cells. If the results of the blood tests are not normal, more blood tests may have to be done.

The doctor may also do a bone marrow biopsy . During this test, a needle is inserted into a bone. A small amount of bone marrow is taken out and looked at under the microscope. The doctor can then tell what kind of leukemia the patient has and plan the best treatment. The chance of recovery (prognosis) depends on how many cancer cells are in the blood and bone marrow, and the patient's age and general health.

Stages

There is no staging system for hairy cell leukemia. Patients are grouped together based on whether or not they have been treated for their leukemia.

Untreated
No treatment has been given for the leukemia. Treatment may have been given for infections or other side effects of the leukemia.

Progressive
Splenectomy (surgery to remove the spleen) has been done or systemic therapy (treatment that uses substances that travel through the bloodstream, reaching and affecting cells all over the body) has been given, but the leukemia is getting worse.

Refractory
The leukemia has been treated but no longer responds to the treatment.

Treatment of hairy cell leukemia

Some people with hairy cell leukemia have few symptoms and may not need treatment right away. There are treatments for all patients with hairy cell leukemia that is causing symptoms. Three kinds of treatment are used:

• Surgery
• Chemotherapy (using drugs to kill cancer cells)
• Biological therapy (using the body's immune system to fight cancer)

Bone marrow transplants are being tested in clinical trials.

Surgery

If the spleen is swollen, the doctor may take out the spleen in an operation called a splenectomy .

Chemotherapy

Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in the vein, muscle, or under the skin. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells throughout the body.

Biological therapy

Biological therapy tries to get the body to fight the cancer. It uses materials made by the body or made in a laboratory to boost, direct, or restore the body's natural defenses against disease. Biological therapy is sometimes called biological response modifier (BRM) therapy or immunotherapy . Interferon, a substance made by the body to fight off foreign materials, is often used to treat hairy cell leukemia.

Bone marrow transplantation

Bone marrow transplantation is used to replace the bone marrow with healthy bone marrow. First, all of the bone marrow in the body is destroyed with high doses of chemotherapy with or without radiation therapy. Healthy marrow is then taken from another person (a donor) whose tissue is the same as or almost the same as the patient's. The donor may be a twin (the best match), a brother or sister, or another unrelated person. The healthy marrow from the donor is given to the patient through a needle in the vein. The marrow replaces the marrow that was destroyed. Bone marrow transplants using marrow from a relative or unrelated person is called an allogeneic bone marrow transplant .

Treatment by stage

Standard treatment may be considered because of its effectiveness in patients in past studies. Participation in a clinical trial may be considered as well. Not all patients are cured with standard therapy. Some standard treatments may have more side effects than are desired. For these reasons, clinical trials are designed to find better ways to treat cancer patients. They are based on the most up-to-date information. Clinical trials are ongoing in most parts of the country for patients with hairy cell leukemia. To learn more about clinical trials, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.

Untreated

Treatment may be one of the following:

1. If there are no symptoms, treatment may not be needed. The doctor will follow the patient closely so treatment can be started if the leukemia gets worse.
2. Biological therapy
3. Chemotherapy
4. Surgery to remove the spleen (splenectomy)

Refractory

If the patient has not responded to biological therapy, chemotherapy may be given. The patient may also wish to take part in a clinical trial of new chemotherapy drugs.