Hairy cell leukemia (HCL) is a rare form of cancer involving white blood cells called B lymphocytes. White blood cells protect the body from infections and cancers. HCL gets its name from the tiny hair-like projections that protrude from the surface of HCL cancer cells. Illness results from the accumulation of these cancer cells in the bone marrow and spleen.
Cancer occurs when cells in the body (in this case white blood cells) divide without control or order. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms, called a growth or tumor. The term cancer refers to malignant tumors, which can invade nearby tissues and can spread to other parts of the body. A benign tumor usually does not invade or spread.
Causes
The exact cause of HCL is unknown.
Risk Factors
A risk factor is something that increases your chances of getting a disease or condition. Specific risk factors for HCL are unknown. However, the disease tends to occur more often in men and in people over the age of 50.
Symptoms
HCL tends to develop slowly over a number of years. It often causes no symptoms at first. Eventually, the accumulation of cancer cells interferes with the normal function of the bone marrow, which often leads to a deficiency of red blood cells (anemia), white blood cells, and platelets.
Symptoms may include:
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Weakness and fatigue (due to anemia)
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Enlarged spleen
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Enlarged liver
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Recurrent infections, often with fevers (due to low white cell count)
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Ease in bruising and bleeding (due to low platelet count)
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Night sweats
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Swollen lymph nodes (rare)
Diagnosis
The doctor will ask about your symptoms and medical history, and perform a physical exam. Tests may include:
Treatment
HCL is a slow-growing cancer that does not require aggressive treatment early on. As HCL progresses, treatment may include:
Surgery–if HCL causes the spleen to enlarge, the spleen may be surgically removed (called a splenectomy)
Chemotherapy–the use of drugs to kill cancer cells. Chemotherapy may be given in many forms including: pill, injection, and via catheter. The drugs enter the bloodstream and travel through the body killing mostly cancer cells, but also some healthy cells. Several new drugs show promise in the treatment of hairy cell leukemia, and initial chemotherapy is becoming more common as new drugs are found that work well in managing the disease.
Immunotherapy–the use of drugs like interleukin-2 and interferon to help boost the immune system to better fight and destroy cancer cells. It is also called biotherapy.
Bone Marrow Transplant–in this procedure, a patient's bone marrow is destroyed with high doses of chemotherapy and/or radiation. The bone marrow is then replaced with healthy bone marrow from another person (the donor) whose tissue closely matches the tissue of the patient.
Treatment of Symptoms–HCL patients with anemia often receive blood transfusions. Those with recurrent infections may receive antibiotics and/or other drugs to fight the infections.
Prevention
There are no guidelines for preventing HCL because the exact cause is unknown.
RESOURCES:
American Cancer Society
http://www.cancer.org
The Leukemia & Lymphoma Society
http://www.leukemia.org
National Cancer Institute
http://www.cancernet.nci.nih.gov
References:
The Leukemia & Lymphoma Society website. Available at: http://www.leukemia.org.
The Merck Manual of Medical Information. Simon and Schuster, Inc.; 2000.
National Cancer Institute website. Available at: http://www.cancernet.nci.nih.gov.
US National Library of Medicine website. Available at: http://www.nlm.nih.gov/.
