Hairy Cell

Highlights • Hairy cell leukemia (HCL) is a rare gene cause the B-cell to become slow-growing type of cancer. harmful or malignant, growing and multiplying uncontrollably. These harmful It is called hairy cell • A person with HCL usually has leukemia because an enlarged and a low blood cells enter the and spleen, under a , cell count making them more prone and they may also attack the liver these malignant cells to infections, bruising/bleeding and occasionally the lymph nodes. have short, thin hair-like and . Once inside the bone marrow, these projections on their • HCL cannot be cured but recent hairy cells reduce the development surface. advances in treatment have made of red blood cells, and white it possible for many HCL patients blood cells. When this happens, your to survive longer than before. normal blood cell count goes down • In most patients, the disease will making you more prone to infections, return and require more treatment. excessive bleeding and/or anemia. HCL progresses slowly and is Revised June 2019 considered a chronic form of leukemia – Introduction a disease you will live with for a long Hairy cell leukemia is an uncommon period of time. Doctors will typically wait cancer that starts in a B-cell (an important until symptoms appear or get worse cellular component in your body’s before beginning treatment. The main ). Changes in a B-cell treatment for HCL is , and for many patients it is effective in extending survival that can last years. Signs and Symptoms Even with a successful first treatment, The signs and symptoms of HCL are not however, the cancer will return in many unique and may resemble those of other patients and they will require additional less serious illnesses. HCL patients often therapy. feel unwell as a result of low levels There is currently no cure for HCL. of normal blood cells.

Rarely, changes to the B-cell produce You may experience these signs an unrelated hairy cell leukemia variant and symptoms: (HCL-V), which accounts for about 10% Fatigue, paleness and shortness of all HCL cases. HCL-V cells are more of breath aggressive than the classic HCL cells having their own cell characteristics • when your count is low and requiring different treatment. (anemia) Easy bleeding or bruising Incidence and Risk Factors • when the number of platelets in your bone marrow decrease HCL is an uncommon leukemia affecting () more men than women. It is unknown what causes HCL, but there are known Higher risk of infection risk factors that may increase a person’s • when you have a lower number chance of developing the disease. of and monocytes – types These risk factors include: of white blood cells that fight infection • Genetic mutation: having ( and monocytopenia) a BRAFV600E gene mutation. You may also experience: • Age: the median age at diagnosis • fever is about 58 years. • weakness • Sex: more men than women are diagnosed with HCL. • unexplained weight loss • pain below the ribs caused • Exposure to chemicals: a strong by an enlarged swollen spleen presence of HCL among people who have been exposed to herbicides such as . llscanada.org | 1 833 222-4884 Hairy Cell Leukemia | 2 Diagnosis • This test classifies cells according HCL can easily be confused with other to their cell surface proteins. HCL blood diseases. For this reason, it is cells have a characteristic cell surface important that you obtain an accurate protein pattern that is different from diagnosis in order to determine the both healthy B-cells and other types best treatment option. Meeting with of abnormal B-cells. a hematologist-oncologist to undergo a thorough medical history and physical Molecular tests examination is your first step to reaching • These are very sensitive DNA tests a diagnosis. During the examination, that check for specific genetic the doctor will look for signs of infection changes in cells. In almost all cases and disease, such as, enlarged lymph of HCL, the leukemia cells have nodes. a mutation of a specific gene, which Laboratory tests used to diagnose helps to identify HCL from other HCL include: B-cell and . (CBC) Imaging with differential • A CT scan/or ultrasound may be used • This test measures the number of when there needs to be an red blood cells, platelets and white examination for a possible enlarged blood cells in a sample of your blood. spleen, liver and/or lymph nodes. The “differential” measures the different types of white blood cells. Usually, a person with HCL has low Treatment Planning counts of white blood cells, red blood cells and platelets. Your treatment depends on many factors. Test results help doctors predict how Peripheral blood smear your HCL will likely progress and what • In this test, a microscope is used your likely response to the treatment to count your blood cells and will be. Favourable risk factors are linked to check if the blood cells appear to a lower risk that HCL will return normal. Cells that appear small after treatment. Poor risk factors are to medium-sized with the presence associated with a higher risk that HCL of hair-like projections are HCL cells. will return after treatment. Bone marrow aspiration and biopsy The following poor risk factors are associated with a shorter remission after • These two procedures examine chemotherapy treatment using single your bone cells for abnormalities. agent purine analog (see Treatment For a bone marrow aspiration, a special biopsy needle is inserted below): through the hip bone and into the • enlarged spleen marrow in order to extract a liquid • hairy cells in the blood sample of cells. For a bone marrow • unmutated IGHV gene biopsy, a wider needle is used to remove a sample of solid bone Risk factors give a general indication that contains marrow. for what likely response you may

llscanada.org | 1 833 222-4884 Hairy Cell Leukemia | 3 determined by doctor experience, patient-related factors (i.e. drug allergy) and availability in your region. The drugs are effective in approximately 80 to 85 per cent of patients. Most patients receiving these drugs as first-line treatment achieve a complete remission that can last for several years. have to treatment, but every patient’s A complete remission means: medical situation is unique. Talk to your hematologist-oncologist about • normal blood count level risk factors specific to you and ask • disappearance of hairy leukemia cells your medical team about all treatment from the blood and bone marrow options including clinical trials. Visit • reduction in the size of the spleen LLSCanada.org for more information. • absence of disease symptoms Treatment Side Effects of Treatment The start of treatment will vary from one patient to another. If your blood count Before starting treatment, you may already is stable and you have no symptoms have a low count, at the time of your diagnosis, you may resulting in a severe, active infection. be treated with an active surveillance Before starting chemotherapy you or watch-and-wait approach. A watch- should consult with a HCL specialist and-wait approach means that treatment since the treatment will reduce your is delayed until signs and symptoms white blood cell count even further. of HCL appear or get worse. Some HCL This can cause a condition called patients live many symptom-free years neutropenia where there is a lower than on the watch-and-wait approach without normal number of neutrophils, the receiving any treatment. Frequent white blood cells that help fight infection. monitoring, including blood tests, will While in treatment, you will be at greater help doctors decide when treatment risk of developing a serious infection. should be started if it shows the disease Doctors may prescribe an antibiotic is beginning to advance. to prevent infections or prescribe On the other hand, your treatment a treatment to help your body produce will begin right away if you have blood more white blood cells. counts below normal levels or show symptoms including unexplained weight Treatment for Patients with loss, infections that keep coming back or physical discomfort due to an Refractory or Relapsed HCL enlarged spleen or liver. Some patients do not respond to Most often HCL treatment involves treatment while others respond at first, chemotherapy with a purine analog. but over time, their disease returns The choice between the drugs is usually and they require further treatment.

llscanada.org | 1 833 222-4884 Hairy Cell Leukemia | 4 Refractory Disease Current clinical trials include:

If you do not respond to primary BRAF Inhibitors treatment, it is called refractory • Almost all HCL patients have disease. When this happens, you will a mutated gene, which makes be treated with a different drug or the BRAF protein responsible for in combination with a monoclonal the production of HCL cancer cells. antibody. BRAF inhibitor stops production of the BRAF protein. Relapsed Disease B-cell Receptor Inhibitors When the disease returns after • Bruton’s tyrosine kinase (BTK) is treatment, it’s called relapsed disease. an enzyme protein on the surface The treatment options for relapsed of B-cells that is responsible for disease depend on the quality and the growth and survival of malignant duration of your first remission. B-cells. The BTK inhibitor stops For a relapse after a long remission the growth of these cancer cells of over seven years, you may be given by inactivating the BTK enzyme. purine analog again. In other situations, Immunotoxins you may receive a combination of • Immunotoxins drugs link monoclonal purine analog and monoclonal antibody. antibodies and toxins in order for Sometimes a monoclonal antibody is the monoclonal antibodies to attach given alone if you are unable to receive to the leukemia cell surface and a purine analog. deliver the toxin to kill the cancer cell. Treatments Under Investigation Long-Term Follow-Up Through research, scientists continue to find a cure for HCL and better HCL is a chronic disease so expect therapies for patients with relapsed to have regular checkups and blood disease. Every new drug or treatment tests while in remission. If your blood protocol goes through a series of count starts to decline, you will need to discuss treatment options with clinical trials before it becomes a part your doctors once again. of standard therapy.

LLSC gratefully acknowledges Dr. Versha Banerji, M.D. FRCPC, CancerCare Support for Manitoba, for her important contribution this publication to the content in this publication. provided by

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