Leukemia is a cancer of the blood cells. Blood cells (including red cells that carry oxygen, white cells that fight infection, and platelets that cause blood to clot) are produced in the bone marrow, which is the spongy tissue inside the larger bones in the body. Abnormalities in the bone marrow cells can cause the overproduction or underproduction of certain blood cells. There are four main types of leukemia in adults:
Eosinophilia is a condition that develops when the bone marrow makes too many eosinophils, a type of white blood cell that is involved in allergic reactions or used to fight certain parasites.
Chronic eosinophilic leukemia is a subtype of clonal (from an acquired genetic abnormality) eosinophilia that is sometimes called hypereosinophilic syndrome (HES). This disease is classified as a myeloproliferative disorder (myelo- refers to bone marrow, proliferative means excess).
People can also have high numbers of eosinophils without having cancer. For example, sometimes the body makes too many eosinophils in response to an allergen or a parasite. This type of eosinophilia is called secondary eosinophilia and is much more common than eosinophilic leukemia.
This section focuses on chronic eosinophilic leukemia. Acute eosinophilic leukemia is rare and is treated similarly to acute myeloid leukemia (AML); read the Cancer.Net Guide: Acute Myeloid Leukemia for more information.
Statistics
Eosinophilic leukemia is rare; no specific statistics are available.
A risk factor is anything that increases a person’s chance of developing cancer. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health-care choices.
Leukemia can be caused by a genetic mutation brought on by heredity or environmental factors (including smoking, chemical, or radiation exposure). However, no specific cause can be identified in most patients with leukemia. The specific cause(s) of eosinophilic leukemia is not known.
People with eosinophilic leukemia may experience the following symptoms. Sometimes, people with eosinophilic leukemia do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not cancer. If you are concerned about a symptom on this list, please talk with your doctor.
Doctors use many tests, such as evaluations of the blood and bone marrow, to diagnose eosinophilia. Although a patient’s signs and symptoms may cause a doctor to suspect eosinophilia, it is diagnosed only by blood tests and bone marrow evaluations. Some tests may also determine which treatments may be the most effective. Your doctor may consider these factors when choosing a diagnostic test:
Age and medical condition
The type of cancer suspected
Severity of symptoms
Previous test results
The main criteria for diagnosing eosinophilic leukemia are:
An eosinophil count in the blood greater than or equal to 1.5 x 109 /L which persists over time
The absence of parasitic, allergic, or other causes of eosinophilia
Organ system involvement or dysfunction directly related to eosinophilia
In addition to a physical examination, the following tests may be used to diagnose eosinophilic leukemia:
Blood tests. The diagnosis of eosinophilic leukemia begins with a routine blood test to measure the number of different types of cells in a person's blood. If the blood contains high levels of eosinophils (see criteria above), eosinophilic leukemia may be present.
Bone marrow biopsy. In a bone marrow biopsy, a doctor takes a sample of marrow, usually from the back of the patient’s hipbone, with a needle. The cells from the marrow, along with the cells from the blood, are analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease) to determine the number and type of abnormal cells. An increased number of immature cells, known as blasts, indicate an acute rather than a chronic eosinophilic leukemia.
If an increased number of eosinophils are found, a molecular genetic analysis should be done testing for a mutation that produces an abnormal protein known as FIP1-like-1/platelet-derived growth factor alpha, because this could help decide the type of treatment which should be given (see below).
Immunophenotyping. Immunophenotyping is the examination of the proteins on the surface of the leukemic cells and allows the doctor to confirm the exact type of leukemia.
Cytogenetics. Cytogenetics is the examination of the leukemic cells for chromosomal abnormalities. It assists in confirming the diagnosis and may help the doctor determine the person’s prognosis (chance of recovery).
Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail. A CT scan also shows enlarged lymph nodes or a swollen spleen or liver.
Evaluation of the heart. People with high eosinophil counts over a long period of time frequently have disturbances in heart function and rhythm. The doctor may recommend an electrocardiogram (ECG or EKG, a test that records the electrical activity of the heart to show whether there are abnormal rhythms or to detect damage) and/or an echocardiogram (a procedure that evaluates the structure and function of the heart using sound waves and an electronic sensor).
Staging is a way of describing a cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis. There are different stage descriptions for different types of cancer.
Unlike most solid tumors, leukemias do not have a formal staging system. Chromosomal abnormalities are the main indicators used to monitor a person’s recovery from eosinophilic leukemia, as well as the disease’s response to treatment and the percentage of immature cells in the bone marrow.
The treatment of eosinophilic leukemia depends on various factors, including the patient’s overall health. In many cases, a team of doctors will work with the patient to determine the best treatment plan.
According to the National Cancer Institute, the best treatment for eosinophilic leukemia remains unclear. Patients are encouraged to consider clinical trials as a treatment option when making treatment plan decisions. A clinical trial is a research study to test a new treatment to prove it is safe, effective, and possibly better than standard treatment. Your doctor can help you review all treatment options. For more information, visit the Clinical Trials section.
As explained in the Overview, eosinophilic leukemia is classified as a myeloproliferative disorder. General treatments for myeloproliferative disorders include chemotherapy, radiation therapy, surgery, immunotherapy, targeted therapy, steroids, and stem cell/bone marrow transplantation; each treatment is described below. Usually, myeloproliferative disorders cannot be cured, but treatment helps to control the symptoms.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. The side effects of chemotherapy depend on the individual and the dose used, but can include fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually go away once treatment is finished.
Chemotherapy used in treating eosinophilic leukemia include hydroxyurea (Droxia, Hydrea), cyclophosphamide (Clafen, Cytoxan, Neosar), and vincristine (Oncovin).
The medications used to treat cancer are continually being evaluated. Talking with your doctor is often the best way to learn about the medications prescribed for you, their purpose, and their potential side effects or interactions with other medications. Learn more about your prescriptions through Cancer.Net’s Drug Information Resources, which provides links to searchable drug databases.
Radiation therapy
Radiation therapy is the use of high-energy x-rays or other particles to kill cancer cells. The most common type of radiation therapy is called external-beam radiation therapy, which is radiation given from a machine outside the body. When radiation therapy is given using implants, it is called internal radiation therapy or brachytherapy. Radiation therapy for eosinophilic leukemia is generally used as a palliative treatment (care given to improve quality of life by treating symptoms and side effects of the cancer or its treatment).
Side effects from radiation therapy include fatigue, mild skin reactions, upset stomach, and loose bowel movements. Most side effects go away soon after treatment is finished.
Surgery
Surgery to remove the spleen (splenectomy), which also produces white blood cells, may occasionally be performed.
Immunotherapy
Immunotherapy (also called biologic therapy), is designed to boost the body's natural defenses to fight the cancer. It uses materials either made by the body or in a laboratory to bolster, target, or restore immune system function. Recombinant interferon alpha (Alferon N, Roferon-A, Intron A) is a biologic therapy that is occasionally used to treat eosinophilic leukemia.
Targeted therapy
Targeted therapy is a type of treatment that selectively attacks faulty genes or proteins that contribute to cancer growth and development. In many patients with hypereosinophilic syndrome, the leukemic cells have a specific genetic abnormality or mutation that produces an abnormal protein (known as FIP1-like-1/platelet-derived growth factor alpha) that stimulates the cells to grow. Imatinib mesylate (Gleevec) is a drug which inhibits a number of enzymes called tyrosine kinases which Kills abnormal eosinophils by blocking the function of the FIP1-like-1-platelet-derived growth factor alpha protein. Imatinib is more likely to work if this mutation is present; however, if the mutation is not present, there is still a possibility that the disease will respond to the drug. The main side effects of imatinib include swelling around the eyes, leg swelling and cramping, headache, fatigue, rash, and musculoskeletal (joint) pain.
Steroids
Steroid medications are used to control some symptoms of eosinophilic leukemia.
Stem cell transplantation
A stem cell transplant is a medical procedure in which diseased bone marrow is replaced by highly specialized cells, called hematopoietic stem cells. Hematopoietic stem cells are found both in the bloodstream and in the bone marrow. Today, this procedure is more commonly called a stem cell transplant, rather than bone marrow transplant, because blood stem cells are typically what is being transplanted, not the actual bone marrow tissue.
Transplantation is a higher-risk procedure and is not used frequently in people with eosinophilic leukemia because it is not a consistently effective treatment for this disease and because many patients with this disease are older and the risks of the procedure are higher. Before recommending transplantation, doctors will talk with the patient about the risks of this treatment and consider several other factors, such as the type of cancer, results of any previous treatment, and patient’s age and general health.
There are two types of stem cell transplantation depending on the source of the replacement blood stem cells: allogeneic (ALLO) and autologous (AUTO).
In an ALLO transplant, stem cells are obtained from a donor whose tissue matches the patient’s on a genetic level; this testing is called HLA-typing. Most often, a patient’s brother or sister serves as the donor, although unrelated donors can serve as the donor too. Millions of people worldwide have volunteered to donate stem cells for patients who do not have matched family members; matches can be made by searching a computer registry. In addition, a donation of stem cells derived from umbilical cord blood is sometimes considered if family donors are not available.
In an AUTO transplant, the patient’s own stem cells are used. The stem cells are obtained from the patient when he or she is in remission from previous treatment. The stem cells are then frozen until they are needed, usually after the high-dose treatment (explained below) is completed.
In both types, the goal of transplantation is to destroy cancer cells in the marrow, blood, and other parts of the body and have replacement blood stem cells create healthy bone marrow. In most stem cell transplants, the patient is treated with high doses of chemotherapy and/or radiation therapy to destroy as many cancer cells as possible. This also destroys the patient’s bone marrow tissue and suppresses the patient’s immune system so that, in an ALLO transplant, the donor cells are not rejected by the body. After the high-dose treatment is given, blood stem cells are infused into the patient’s vein to replace the bone marrow and restore normal blood counts from donor cells. Sometimes, ALLO transplants can also be performed after giving lower doses of chemotherapy and/or radiation therapy that are still sufficient to suppress the immune system and allow growth of the donor cells. These transplants, sometimes termed “mini-transplants” or “reduced intensity transplants” have less immediate side effects, allowing the procedure to be used for older patients.
For both ALLO and AUTO transplant types, the replacement cells engraft (begin to make new blood cells) and turn into healthy, blood-producing tissue in 10 days to three weeks. Destroying the patient’s own marrow reduces the body’s natural defenses, temporarily leaving the patient at an increased risk of infection. Until the patient’s immune system is back to normal, patients may need antibiotics and blood transfusions.
In an ALLO transplant, another major risk is that the donor’s cells will recognize the patient’s body as foreign, causing graft-versus-host disease (GVHD). GVHD may be a serious complication of allogeneic transplants and can be fatal. Other side effects may include liver problems, diarrhea, infections, and rashes. However, GVHD can also be a benefit, in that the donor cells can recognize the cancer cells as foreign and destroy these cells, a mechanism that is one of the major reasons why ALLO transplantation can eliminate certain types of leukemia over the long term. The risk of GVHD can be reduced with exact HLA-type matching and the use of preventative drugs.
In an AUTO transplant, there is little risk of GVHD because the replacement stem cells are the patient’s own cells. However, there is a risk in an autologous transplant that some of the cells that are put back into the patient could still be cancerous.
Doctors and scientists are always looking for better ways to treat patients with eosinophilic leukemia. A clinical trial is a way to test a new treatment to prove that it is safe, effective, and possibly better than a standard treatment. Patients who participate in clinical trials are among the first to receive new treatments before they are widely available. However, there is no guarantee that the new treatment will be safe, effective, or better than a standard treatment.
Patients decide to participate in clinical trials for many reasons. For some patients, a clinical trial is the best treatment option available. Because standard treatments are not perfect, patients are often willing to face the added uncertainty of a clinical trial in the hope of a better result. Other patients volunteer for clinical trials because they know that finding new drugs and other therapies is the only way to make progress in treating eosinophilic leukemia. Even if they do not benefit directly from the clinical trial, their participation may benefit future patients with eosinophilic leukemia.
To join a clinical trial, patients must complete a learning process known as informed consent. During informed consent, the doctor should list all of the patient’s options, so the person understands how the new treatment differs from the standard treatment. The doctor must also list all of the risks of the new treatment, which may or may not be different from the risks of standard treatment. Finally, the doctor must explain what will be required of each patient in order to participate in the clinical trial, including the number of doctor visits, tests, and the schedule of treatment. Learn more about Clinical Trials, including patient safety, phases of a clinical trial, deciding to participate in a clinical trial, questions to ask the research team, and links to find cancer clinical trials.
Cancer and its treatment can cause a variety of side effects. However, doctors have made major strides in recent years in reducing pain, nausea and vomiting, and other physical side effects of cancer treatments. Many treatments used today are less intensive but as effective as treatments used in the past. Doctors also have many ways to provide relief to patients when such side effects do occur.
Fear of treatment side effects is common after a diagnosis of cancer, but it may be helpful to know that preventing and controlling side effects is a major focus of your health-care team. Before treatment begins, talk with your doctor about possible side effects of the specific treatments you will be receiving. The specific side effects that can occur depend on a variety of factors, including the type of cancer, its location, the individual treatment plan (including the length and dosage of treatment), and the person’s overall health.
Ask your doctor which side effects are most likely to happen (and which are not), when side effects are likely to occur, and how they will be addressed by the health-care team if they do happen. Also, be sure to communicate with the doctor about side effects you experience during and after treatment. For more information on the most common side effects of cancer and different treatments, along with ways to prevent or control them, visit Cancer.Net’s section on Managing Side Effects, based on ASCO’s curriculum.
In addition to physical side effects, there may be psychosocial (emotional and social) effects as well. Learn more about the importance of addressing these needs in Cancer.Net’s section on Caring for the Whole Patient.
For more information on late effects or long-term side effects, please read the After Treatment section or talk with your doctor.
After treatment for eosinophilic leukemia ends, talk with your doctor about developing a follow-up care plan. This plan may include regular physical examinations, blood tests, bone marrow biopsies, and possibly scans or other imaging studies to monitor your recovery for the coming months and years. People experiencing a long-term remission are encouraged to follow cancer screening recommendations for the general population.
Some cancer treatments may cause long-term side effects.
Numbness, tingling, and pain in the hands and feet may occur in people who have received vincristine.
Heart damage in the form of a weakened heart muscle may occur in people who have received a higher total dose of doxorubicin (Adriamycin) or radiation therapy to the chest.
Infertility or premature menopause can occur in people who have received high-dose cyclophosphamide or other chemotherapy.
A secondary leukemia or a secondary cancer (cancer that develops because of the treatment for another type of cancer) is more common in people who were treated with chemotherapy and radiation therapy.
Talk with your health-care team about the best ways to manage these side effects.
People recovering from eosinophilic leukemia are encouraged to follow established guidelines for good health, such as maintaining a healthy weight, not smoking, eating a balanced diet, and having recommended cancer screening tests. Talk with your doctor to develop a plan that is best for your needs. Moderate physical activity can help rebuild your strength and energy level. Your doctor can help you create an appropriate exercise plan based upon your needs, physical abilities, and fitness level. Learn more about Healthy Living After Cancer.
Research for eosinophilic leukemia and other myeloproliferative disorders is ongoing. The following advances may still be under investigation in clinical trials and may not be approved or available at this time. Always discuss all diagnostic and treatment options with your doctor.
Genetic research. Because this type of disorder is usually associated with a genetic mutation, researchers are searching for specific genetic markers (the presence or absence of specific genes or mutations that can indicate cancer).
Expanded use of transplantation. New protocols for stem cell/bone marrow transplantation are being tested.
New treatments. Better combinations of chemotherapy and additional treatment combinations are also being explored, as is the drug mepolizumab (Bosatria). Mepolizumab is a humanized monoclonal antibody that binds specifically to human interleukin 5 (hIL-5) and inhibits its activity. Preliminary studies in people have shown that mepolizumab lowers blood eosinophilia in people with allergies and HES and has alleviated some clinical signs and symptoms of HES.
Regular communication with your doctor is important for making informed decisions about your health care. Consider asking the following questions of your doctor:
What type of leukemia do I have?
Can you explain my pathology report to me?
How will the cancer develop? Is it possible to slow or delay this development?
Is it curable?
How can my symptoms be controlled?
What are my treatment options?
What clinical trials are open to me?
What treatment do you recommend and why?
What are the possible side effects of this treatment, both in the short term and the long term?
How will this treatment affect my daily life? Will I be able to work, exercise, and perform my usual activities?
How can I keep myself as healthy as possible during and after treatment?
What follow-up tests will I need, and how often will I need them?
What support services are available to me? To my family?
Rare Cancer Alliance
1649 N. Pacana Way
Green Valley, AZ 85614 www.rare-cancer.org
American Society for Blood and Marrow Transplantation
85 W. Algonquin Rd., Ste. 550
Arlington Heights, IL 60005
Phone: 847-427-0224 www.asbmt.org
Blood and Marrow Transplant Information Network
2310 Skokie Valley Rd., Ste. 104
Highland Park, IL 60035
Toll Free: 888-597-7674
Phone: 847-433-3313 www.bmtinfonet.org
National Bone Marrow Transplant Link
20411 W 12 Mile Rd., Ste. 108
Southfield, MI 48076
Toll Free: 800-LINK-BMT (800-546-5268)
Phone: 248-358-1886 www.nbmtlink.org
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