Leukemia

Definition

Leukemia is a cancer that starts in the organs that make blood, namely the bone marrow and the lymph system. Depending on specific characteristics, leukemia can be divided into two broad types: acute and chronic. Acute leukemias are the rapidly progressing leukemias, while the chronic leukemias progress more slowly. The vast majority of childhood leukemias are of the acute form.

Description

The cells that make up blood are produced in the bone marrow and the lymph system. The bone marrow is the spongy tissue found in the large bones of the body. The lymph system includes the spleen (an organ in the upper abdomen), the thymus (a small organ beneath the breastbone), and the tonsils (an organ in the throat). In addition, the lymph vessels (tiny tubes that branch like blood vessels into all parts of the body) and lymph nodes (pea-shaped organs that are found along the network of lymph vessels) are also parts of the lymph system. The lymph is a milky fluid that contains cells. Clusters of lymph nodes are found in the neck, underarm, pelvis, abdomen, and chest.

The cells found in the blood are the red blood cells (RBCs), which carry oxygen and other materials to all tissues of the body; white blood cells (WBCs) that fight infection; and platelets, which play a part in the clotting of the blood. The white blood cells can be further subdivided into three main types: granulocytes, monocytes, and lymphocytes.

The granulocytes, as their name suggests, have particles (granules) inside them. These granules contain special proteins (enzymes) and several other substances that can break down chemicals and destroy microorganisms, such as bacteria. Monocytes are the second type of white blood cell. They are also important in defending the body against pathogens.

The lymphocytes form the third type of white blood cell. There are two main types of lymphocytes: T lymphocytes and B lymphocytes. They have different functions within the immune system. The B cells protect the body by making "antibodies." Antibodies are proteins that can attach to the surfaces of bacteria and viruses. This "attachment" sends signals to many other cell types to come and destroy the antibody-coated organism. The T cells protect the body against viruses. When a virus enters a cell, it produces certain proteins that are projected onto the surface of the infected cell. The T cells recognize these proteins and make certain chemicals that are capable of destroying the virus-infected cells. In addition, the T cells can destroy some types of cancer cells.

The bone marrow makes stem cells, which are the precursors of the different blood cells. These stem cells mature through stages into either RBCs, WBCs, or platelets.

Chronic leukemias

In chronic leukemias, the cancer starts in the blood cells made in the bone marrow. The cells mature and only a few remain as immature cells. However, even though the cells mature and appear normal, they do not function as normal cells. Depending on the type of white blood cell that is involved, chronic leukemia can be classified as chronic lymphocytic leukemia or chronic myelogenous leukemia.

Chronic leukemias develop very gradually. The abnormal lymphocytes multiply slowly, but in a poorly regulated manner. They live much longer and thus their numbers build up in the body. The two types of chronic leukemias can be easily distinguished under the microscope. Chronic lymphocytic leukemia (CLL) involves the T or B lymphocytes. B cell abnormalities are more common than T cell abnormalities. T cells are affected in only 5% of the patients. The T and B lymphocytes can

be differentiated from the other types of white blood cells based on their size and by the absence of granules inside them. In chronic myelogenous leukemia (CML), the cells that are affected are the granulocytes.

Chronic lymphocytic leukemia (CLL) often shows no early symptoms and may remain undetected for a long time. Chronic myelogenous leukemia (CML), on the other hand, may progress to a more acute form.

Acute leukemias

In acute leukemia, the maturation process of the white blood cells is interrupted. The immature cells (or "blasts") proliferate rapidly and begin to accumulate in various organs and tissues, thereby affecting their normal function. This uncontrolled proliferation of the immature cells in the bone marrow affects the production of the normal red blood cells and platelets as well.

Acute leukemias are of two types: acute lymphocytic leukemia and acute myelogenous leukemia. Different types of white blood cells are involved in the two leukemias. In acute lymphocytic leukemia (ALL), the T or B lymphocytes become cancerous. The B cell leukemias are more common than T cell leukemias. Acute myelogenous leukemia, also known as acute nonlymphocytic leukemia (ANLL), is a cancer of the monocytes and/or granulocytes.

Leukemias account for 2% of all cancers. Because leukemia is the most common form of childhood cancer, it is often regarded as a disease of childhood. However, leukemias affect nine times as many adults as children. Half of the cases occur in people who are 60 years of age or older. The incidence of acute and chronic leukemias is about the same. According to the estimates of the American Cancer Society (ACS), approximately 29,000 new cases of leukemia were diagnosed in 1998. Internationally, leukemia is the fourth most common cancer among people age 15 to 19 years old.

Causes & symptoms

Leukemia strikes both sexes and all ages and its cause is mostly unknown. However, chronic leukemia has been linked to genetic abnormalities and environmental factors. For example, exposure to ionizing radiation and to certain organic chemicals, such as benzene, is believed to increase the risk for getting leukemia. A 2003 study from the Electric Power Research Institute showed possible links between metallic drainpipes and childhood baths. Chronic leukemia occurs in some people who are infected with two human retroviruses (HTLV-I and HTLV-II). An abnormal chromosome known as the Philadelphia chromosome is seen in 90% of those with CML. The incidence of chronic leukemia is slightly higher among men than women.

Acute lymphoid leukemia (ALL) is more common among Caucasians than among African-Americans, while acute myeloid leukemia (AML) affects both races equally. The incidence of acute leukemia is slightly higher among men than women. People of Jewish ancestry have a higher likelihood of getting leukemia. A higher incidence of leukemia has also been observed among persons with Down syndrome and some other genetic abnormalities.

A history of diseases that damage the bone marrow, such as aplastic anemia , or a history of cancers of the lymphatic system puts people at a high risk for developing acute leukemias. Similarly, the use of anticancer medications, immunosuppressants, and the antibiotic chloramphenicol also are considered risk factors for developing acute leukemias.

The symptoms of leukemia are generally vague and non-specific. A patient may experience all or some of the following symptoms:

• weakness or chronic fatigue
• fever of unknown origin
• weight loss that is not due to dieting or exercise
• frequent bacterial or viral infections
• headaches
• skin rash
• non-specific bone pain
• easy bruising
• bleeding from gums or nose
• blood in urine or stools
• enlarged lymph nodes and/or spleen
• abdominal fullness

Diagnosis

Like all cancers, leukemias are best treated when found early. There are no screening tests available. If the doctor has reason to suspect leukemia, he or she will conduct a thorough physical examination to look for enlarged lymph nodes in the neck, underarm, and pelvic region. Swollen gums, enlarged liver or spleen, bruises , or pinpoint red rashes all over the body are some of the signs of leukemia. Urine and blood tests may be ordered to check for microscopic amounts of blood in the urine and to obtain a complete differential blood count. This count will give the numbers and percentages of the different cells found in the blood. An abnormal blood test might suggest leukemia, however, the diagnosis has to be confirmed by more specific tests.

A doctor may perform a bone marrow biopsy to confirm the diagnosis of leukemia. During the biopsy, a cylindrical piece of bone and marrow is removed, generally from the hip bone. These samples are sent to the laboratory for examination. In addition to diagnosis, the biopsy is also repeated during the treatment phase of the disease to see if the leukemia is responding to therapy.

A spinal tap (lumbar puncture) is another procedure that the doctor may order to diagnose leukemia. In this procedure, a small needle is inserted into the spinal cavity in the lower back to withdraw some cerebrospinal fluid and to look for leukemic cells.

Standard imaging tests, such as x rays, computed tomography scans (CT scans), and magnetic resonance imaging (MRI) may be used to check whether the leukemic cells have invaded other areas of the body, such as the bones, chest, kidneys, abdomen, or brain. A gallium scan or bone scan is a test in which a radioactive chemical is injected into the body. This chemical accumulates in the areas of cancer or infection, allowing them to be viewed with a special camera.

Treatment

Alternative therapies should be used only as complementary to conventional treatment, not to replace it. Before participating in any alternative treatment programs, patients should consult their doctors concerning the appropriateness and the role of such programs in the overall cancer treatment plan. Appropriate alternative treatments can help prolong a patient's life or at least improve quality of life, prevent recurrence of tumors or prolong the remission period, and reduce adverse reactions to chemotherapy and radiation.

The effectiveness of most anti-cancer drugs used to treat leukemia can be reduced when patients take mega doses of antioxidants. These antioxidants , in patients not undergoing chemotherapy, can be very helpful in protecting the body against cancer. However, taken during chemotherapy, these antioxidants protect the cancer cells from being killed by treatment. Because high-dose supplementation of antioxidants can interfere with conventional chemotherapy treatment, patients should only take them at dosages much above the recommended daily allowance (RDA).

Dietary guidelines

The following dietary changes may be helpful:

• Avoiding fatty and spicy foods, which may be harder to digest.
• Eating new and exciting foods. Tasty foods stimulate appetite so that patients can eat more and have the energy to fight cancer.
• Increasing consumption of fresh fruits and vegetables. They are nature's best sources of antioxidants, as well as vitamins and minerals.
• Eating multiple (five or six) meals per day. Small meals are easier to digest.
• Establishing regular eating times and not eating around bedtime.
• Avoiding foods that contain preservatives or artificial coloring.
• Monitoring weight and eating adequate calories and protein.

Nutritional supplements

A naturopath or nutritional physician may recommend some of the following nutritional supplements to boost a patient's immune function and help fight cancer:

• Vitamins and minerals. Vitamins that are of particular benefit to cancer patients include beta-carotene, B-complex vitamins, (especially vitamin B6, vitamins A, C, D, E and K. The most important minerals are calcium, chromium, copper, iodine , molybdenum, germanium, selenium, tellurium, and zinc . Many of these vitamins and minerals are strong antioxidants. However, patients should not take mega doses of these supplements without first consulting their doctor. Significant adverse or toxic effects may occur at high dosage, which is especially true for minerals. It is prudent to avoid use of antioxidants when undergoing chemotherapy or radiation therapy since these treatments kill the cancer by producing oxidants. Antioxidants can undermine the effectiveness of treatment.
• Other nutritional supplements that may help fight cancer and support the body include essential fatty acids (fish or flaxseed oil), flavonoids, pancreatic enzymes (to help digest foods), hormones such as DHEA , melatonin or phytoestrogens, rice bran, and mushroom extracts. It is best to check with a nutritional physician or other licensed provider when adding these supplements.

Traditional Chinese medicine

Conventional treatment for leukemia is associated with significant side effects. These adverse effects can be reduced with Chinese herbal preparations. Patients should consult an experienced herbalist who will prescribe remedies to treat specific symptoms that are caused by conventional cancer treatments.

Juice therapy

Juice therapy may be helpful in patients with cancer. Patients should mix one part of pure juice with one part of water before drinking. Daily consumption of the following juice may be helpful by reducing toxic burden to the liver:

• carrot and beet juice with a touch of radish or dandelion root
• grapes, pear, and lemon
• carrot, celery, and parsley
• carrot, beet, and cucumber juices

Homeopathy

There is conflicting evidence regarding the effectiveness of homeopathy in cancer treatment. Because cancer chemotherapy may suppress the body's response to homeopathic treatment, homeopathy may not be effective during chemotherapy. Therefore, patients should wait until after chemotherapy to try this relatively safe alternative treatment.

Acupuncture

Acupuncture is the use of needles on the body to stimulate or direct the meridians (channels) of energy flow in the body. Acupuncture has not been shown to have any anticancer effects. However, it is an effective treatment for nausea , a common side effect of chemotherapy and radiation.

Other treatments

Other therapies that may help the leukemia patient include meditation, qigong, yoga , and t'ai chi , all of which can aid in stress reduction. Guided imagery can increase immune function and decrease pain and nausea.

Allopathic treatment

There are two phases of treatment for leukemia. The first phase is called induction therapy. The main aim of the treatment is to reduce the number of leukemic cells as far as possible and induce a remission in the patient. Once the patient shows no obvious signs of leukemia (no leukemic cells are detected in blood tests and bone marrow biopsies), the patient is said to be in remission. The second phase of treatment is then initiated. This is called continuation or maintenance therapy; the aim in this case is to kill any remaining cells and to maintain remission for as long as possible.

Chemotherapy is the use of drugs to kill cancer cells. It is usually the treatment of choice and is used to relieve symptoms and achieve long-term remission of the disease. Generally, combination chemotherapy, in which multiple drugs are used, is more efficient than using a single drug for treatment.

In 2002, scientists announced the discovery of a gene that triggers the death of leukemia cells. Identification of this gene can lead to better targeting of chemotherapy drugs (that involve a vitamin A derivative) for acute promyelocytic leukemia (APL). Another advancement in leukemia treatment occurred in the same year. A new drug was found to cancel the effects of mutations of a gene known as the main culprit in AML, an aggressive, treatment-resistant form of leukemia. Further study was needed on both new discoveries, but they were thought important to improving treatment of two forms of leukemia. Later in 2002, Gleevec, a new antileukemia drug that even proved successful at treating chronic myeloid leukemia, was heralded in clinical trials.

Because leukemia cells can spread to all the organs via the blood stream and lymph vessels, surgery is not considered an option for treating leukemias.

Radiation therapy, which involves the use of x rays or other high-energy rays to kill cancer cells and shrink tumors, may be used in some cases. For acute leukemias, the source of radiation is usually outside the body (external radiation therapy). If the leukemic cells have spread to the brain, radiation therapy can be given to the brain.

Bone marrow transplantation (BMT) is a process in which the patient's diseased bone marrow is replaced with healthy marrow. There are two methods of bone marrow transplant. In an allogeneic bone marrow transplant, healthy marrow is taken from a donor whose tissue is either the same as or very closely resembles the patient's tissue. First, the patient's bone marrow is destroyed with very high doses of chemotherapy and radiation therapy. Healthy marrow from the donor is then given to the patient through a needle in a vein to replace the destroyed marrow.

In the second type of bone marrow transplant, called an autologous bone marrow transplant, some of the patient's own marrow is taken out and treated with a combination of anticancer drugs to kill all abnormal cells. This marrow is then frozen and saved. The marrow remaining in the patient's body is destroyed with high-dose chemotherapy and radiation therapy. The marrow that was frozen is then thawed and given back to the patient through a needle in a vein. This mode of bone marrow transplant is currently being investigated in clinical trials.

Biological therapy or immunotherapy is a mode of treatment in which the body's own immune system is harnessed to fight the cancer. Substances that are routinely made by the immune system (such as growth factors, hormones, and disease-fighting proteins) are either synthetically made in a laboratory or their effectiveness is boosted and they are then put back into the patient's body. This treatment mode is also being investigated in clinical trials all over the country at major cancer centers.

Expected results

Like all cancers, the prognosis for leukemia depends on the patient's age and general health. According to statistics, more than 60% of leukemia patients survive for at least one year after diagnosis.

Acute myelocytic leukemia (AML) has a poorer prognosis rate than acute lymphocytic leukemias (ALL) and the chronic leukemias. In the last 15 to 20 years, the five-year survival rate for patients with ALL has increased from 38% to 57%.

Interestingly enough, since most childhood leukemias are of the ALL type, chemotherapy has been highly successful in their treatment. This is because chemotherapeutic drugs are most effective against actively growing cells. Due to the new combinations of anti-cancer drugs being used, the survival rates among children with ALL have improved dramatically. Eighty percent of the children diagnosed with ALL now survive five years or more, as compared to 50% in the late 1970s.

According to statistics, in chronic lymphoid leukemia, the overall survival for all stages of the disease is nine years. Most of the deaths in people with CLL are due to infections or other illnesses that occur as a result of the leukemia.

In CML, if bone marrow transplantation is performed within one to three years of diagnosis, 50-60% of the patients survive three years or more. If the disease progresses to the acute phase, the prognosis is poor. Less than 20% of these patients go into remission.

Prevention

Most cancers can be prevented by changes in lifestyle or diet, which will reduce risk factors. However, in leukemias, there are no such known risk factors. Therefore, at the present time, there are no real prevention recommendations for leukemia. People who are at an increased risk for developing leukemia because of proven exposure to ionizing radiation or exposure to the toxic liquid benzene, and people with Down syndrome, should undergo periodic medical checkups. Some experts recommend limiting toxic exposures, eating a whole foods diet, refraining from smoking , exercise, and fluids, and even intermittent fasting as possible prevention measures. In 2003, new research found that adult women who took aspirin two or more times a week had a 50% lower risk of developing adult leukemia. Scientists continue to work on a possible vaccine for leukemia. They made some progress in 2002, discovering a gene transfer model that might trigger immunity against leukemia cells.

Resources

BOOKS

Berkow, Robert, et al., eds. Merck Manual of Diagnosis and Therapy, 16th ed. Merck Research Laboratories, 1992.

Dollinger, Malin. Everyone's Guide to Cancer Therapy. Somerville House Books Limited, 1994.

Labriola, Dan. Complementary Cancer Therapies: Combining Traditional and Alternative Approaches for the Best Possible Outcome. Roseville, CA: Prima Health, 2000.

Morra, Marion E. Choices. Avon Books, 1994.

Murphy, Gerald P. Informed Decisions: The Complete Book of Cancer Diagnosis, Treatment and Recovery. American Cancer Society, 1997.

PERIODICALS

"Cancer Killing Gene Found by Dartmouth Researchers." Cancer Weekly (April 9, 2002):17.

"Contact Voltage and Magnetic Fields as Possible Factors in Leukemia — Pilot Study." Journal of Environmental Health (December 2002):47–51.

"Cytokine and CD154 Gene Transfer Generate Immunity Against Leukemia." Immunotherapy Weekly (October 23, 2002):16.

"Drug Blocks Gene Mutation Effect in Lethal Leukemia." Genomics & Genetics Weekly (June 21, 2002):13.

"Leukemia Incidence Lowest in Patients 15-30 Years of Age (Incidence Drops at Age 20)." Internal Medicine News (May 1, 2002):37.

"New Drug Significantly Improves Survival Even for Patients with Late-Stage Disease." Cancer Weekly (December 31, 2002):6.

"Study: Regular Use of Aspirin May Lower Risk of Adult Leukemia." Women's Health Weekly (July 10, 2003):36.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Road, N.E., Atlanta, Georgia 30329. (800) 227-2345. http://www.cancer.org.

Cancer Research Institute. 681 Fifth Avenue, New York, N.Y. 10022. (800) 992-2623. http://www.cancerresearch.org.

The Leukemia and Lymphoma Society. 600 Third Avenue, New York, NY 10016. (800) 955-4572. http://www.leukemia.org.

National Cancer Institute. 9000 Rockville Pike, Building 31, Room 10A16, Bethesda, Maryland, 20892. (800) 422-6237. http://wwwicic.nci.nih.gov.

Oncolink. University of Pennsylvania Cancer Center. http://cancer.med.upenn.edu.

OTHER

Rosenberg, Z'ev. "Treating the Undesirable Effect of Radiation and Chemotherapy with Chinese Medicine." Oriental Chinese Journal. http://www.healthypeople.com.

Mai Tran

Teresa G. Odle

Leukemias, Acute

Definition

Leukemia is a cancer that starts in the organs that make blood, namely the bone marrow and the lymph system. Depending on their characteristics, leukemias can be divided into two broad types. Acute leukemias are the rapidly progressing leukemias, while the chronic leukemias progress more slowly. The vast majority of the childhood leukemias are of the acute form.

Description

The cells that make up blood are produced in the bone marrow and the lymph system. The bone marrow is the spongy tissue found in the large bones of the body. The lymph system includes the spleen (an organ in the upper abdomen), the thymus (a small organ beneath the breastbone), and the tonsils (an organ in the throat). In addition, the lymph vessels (tiny tubes that branch like blood vessels into all parts of the body) and lymph nodes (pea-shaped organs that are found along the network of lymph vessels) are also part of the lymph system. The lymph is a milky fluid that contains cells. Clusters of lymph nodes are found in the neck, underarm, pelvis, abdomen, and chest.

The cells found in the blood are the red blood cells (RBCs), which carry oxygen and other materials to all tissues of the body; white blood cells (WBCs) that fight infection; and the platelets, which play a part in the clotting of the blood. The white blood cells can be further subdivided into three main types: granulocytes, monocytes, and lymphocytes.

The granulocytes, as their name suggests, have particles (granules) inside them. These granules contain special proteins (enzymes) and several other substances that can break down chemicals and destroy microorganisms, such as bacteria. Monocytes are the second type of white blood cell. They are also important in defending the body against pathogens.

The lymphocytes form the third type of white blood cell. There are two main types of lymphocytes: T lymphocytes and B lymphocytes. They have different functions within the immune system. The B cells protect the body by making "antibodies." Antibodies are proteins that can attach to the surfaces of bacteria and viruses. This "attachment" sends signals to many other cell types to come and destroy the antibodycoated organism. The T cells protect the body against viruses. When a virus enters a cell, it produces certain proteins that are projected onto the surface of the infected cell. The T cells recognize these proteins and make certain chemicals that are capable of destroying the virus-infected cells. In addition, the T cells can destroy some types of cancer cells.

The bone marrow makes stem cells, which are the precursors of the different blood cells. These stem cells mature through stages into either RBCs, WBCs, or platelets. In acute leukemias, the maturation process of the white blood cells is interrupted. The immature cells (or "blasts") proliferate rapidly and begin to accumulate in various organs and tissues, thereby affecting their normal function. This uncontrolled proliferation of the immature cells in the bone marrow affects the production of the normal red blood cells and platelets as well.

Acute leukemias are of two types: acute lymphocytic leukemia and acute myelogenous leukemia. Different types of white blood cells are involved in the two leukemias. In acute lymphocytic leukemia (ALL), it is the T or the B lymphocytes that become cancerous. The B cell leukemias are more common than T cell leukemias. Acute myelogenous leukemia, also known as acute nonlymphocytic leukemia (ANLL), is a cancer of the monocytes and/or granulocytes.

CHARLOTTE FRIEND (1921–1987)

Charlotte Friend was born to Russian immigrants, Morris Friend and Cecilia (Wolpin), on March 11, 1921, in New York City. At three years of age, her father died of a heart condition. Friend's decision to pursue a career in medicine may well have been influenced by her father's death and by her mother's occupation as a pharmacist. As a child, Friend read books about bacteriologists and, by age ten, she knew that she wanted to study bacteriology. She attended Hunter College, enlisting in the U.S. Navy after her graduation in 1944.

Friend attended Yale University, earning her Ph.D. in bacteriology in 1950. After working for the Memorial Sloan-Kettering Institute for Cancer Research, she became an associate professor at Cornell University in 1952. Friend began researching cancer and became particularly interested in leukemia and its cause. She believed that a virus caused the disease and confirmed this theory by using an electron microscope to photograph the virus in mice. Her findings were initially met with much skepticism but she was able to develop a vaccine that was used successfully with mice, which added credibility to her theory. Her breakthroughs have led medical researchers to new methods of treating cancer and to a greater understanding of the disease.

Friend was a prolific writer who published 113 original papers, 49 abstracts, book chapters, and reviews, many of which she completed individually. She was diagnosed with lymphoma and died on January 13, 1987.

Leukemias account for 2% of all cancers. Because leukemia is the most common form of childhood cancer, it is often regarded as a disease of childhood. However, leukemias affect nine times as many adults as children. Half of the cases occur in people who are 60 years of age or older. The incidence of acute and chronic leukemias is about the same. According to the estimates of the American Cancer Society (ACS), approximately 29,000 new cases of leukemia were diagnosed in 1998.

Causes and symptoms

Leukemia strikes both sexes and all ages. The human T-cell leukemia virus (HTLV-I) is believed to be the causative agent for some kinds of leukemias. However, the cause of most leukemias is not known. Acute lymphoid leukemia (ALL) is more common among Caucasians than among African-Americans, while acute myeloid leukemia (AML) affects both races equally. The incidence of acute leukemia is slightly higher among men than women. People with Jewish ancestry have a higher likelihood of getting leukemia. A higher incidence of leukemia has also been observed among persons with Down syndrome and some other genetic abnormalities.

Exposure to ionizing radiation and to certain organic chemicals, such as benzene, is believed to increase the risk of getting leukemia. Having a history of diseases that damage the bone marrow, such as aplastic anemia, or a history of cancers of the lymphatic system puts people at a high risk for developing acute leukemias. Similarly, the use of anticancer medications, immunosuppressants, and the antibiotic chloramphenicol are also considered risk factors for developing acute leukemias.

The symptoms of leukemia are generally vague and non-specific. A patient may experience all or some of the following symptoms:

• weakness or chronic fatigue
• fever of unknown origin
• weight loss that is not due to dieting or exercise
• frequent bacterial or viral infections
• headaches
• skin rash
• non-specific bone pain
• easy bruising
• bleeding from gums or nose
• blood in urine or stools
• enlarged lymph nodes and/or spleen
• abdominal fullness

Diagnosis

Like all cancers, acute leukemias are best treated when found early. There are no screening tests available.

If the doctor has reason to suspect leukemia, he or she will conduct a very thorough physical examination to look for enlarged lymph nodes in the neck, underarm, and pelvic region. Swollen gums, enlarged liver or spleen, bruises, or pinpoint red rashes all over the body are some of the signs of leukemia. Urine and blood tests may be ordered to check for microscopic amounts of blood in the urine and to obtain a complete differential blood count. This count will give the numbers and percentages of the different cells found in the blood. An abnormal blood test might suggest leukemia; however, the diagnosis has to be confirmed by more specific tests.

The doctor may perform a bone marrow biopsy to confirm the diagnosis of leukemia. During the biopsy, a cylindrical piece of bone and marrow is removed. The tissue is generally taken out of the hipbone. These samples are sent to the laboratory for examination. In addition to diagnosis, the biopsy is also repeated during the treatment phase of the disease to see if the leukemia is responding to therapy.

A spinal tap (lumbar puncture) is another procedure that the doctor may order to diagnose leukemia. In this procedure, a small needle is inserted into the spinal cavity in the lower back to withdraw some cerebrospinal fluid and to look for leukemic cells.

Standard imaging tests, such as x rays, computed tomography scans (CT scans), and magnetic resonance imaging (MRI) may be used to check whether the leukemic cells have invaded other areas of the body, such as the bones, chest, kidneys, abdomen, or brain. A gallium scan or bone scan is a test in which a radioactive chemical is injected into the body. This chemical accumulates in the areas of cancer or infection, allowing them to be viewed with a special camera.

Treatment

There are two phases of treatment for leukemia. The first phase is called "induction therapy." As the name suggests, during this phase, the main aim of the treatment is to reduce the number of leukemic cells as far as possible and induce a remission in the patient. Once the patient shows no obvious signs of leukemia (no leukemic cells are detected in blood tests and bone marrow biopsies), the patient is said to be in remission. The second phase of treatment is then initiated. This is called continuation or maintenance therapy, and the aim in this case is to kill any remaining cells and to maintain the remission for as long as possible.

Chemotherapy is the use of drugs to kill cancer cells. It is usually the treatment of choice and is used to relieve symptoms and achieve long-term remission of the disease. Generally, combination chemotherapy, in which multiple drugs are used, is more efficient than using a single drug for the treatment. Some drugs may be administered intravenously through a vein in the arm; others may be given by mouth in the form of pills. If the cancer cells have invaded the brain, then chemotherapeutic drugs may be put into the fluid that surrounds the brain through a needle in the brain or back. This is known as intrathecal chemotherapy.

Because leukemia cells can spread to all the organs via the blood stream and the lymph vessels, surgery is not considered an option for treating leukemias.

Radiation therapy, which involves the use of x rays or other high-energy rays to kill cancer cells and shrink tumors, may be used in some cases. For acute leukemias, the source of radiation is usually outside the body (external radiation therapy). If the leukemic cells have spread to the brain, radiation therapy can be given to the brain.

Bone marrow transplantation is a process in which the patient's diseased bone marrow is replaced with healthy marrow. There are two ways of doing a bone marrow transplant. In an allogeneic bone marrow transplant, healthy marrow is taken from a donor whose tissue is either the same as or very closely resembles the patient's tissues. The donor may be a twin, a brother or sister (sibling), or a person who is not related at all. First, the patient's bone marrow is destroyed with very high doses of chemotherapy and radiation therapy. Healthy marrow from the donor is then given to the patient through a needle in a vein to replace the destroyed marrow.

In the second type of bone marrow transplant, called an autologous bone marrow transplant, some of the patient's own marrow is taken out and treated with a combination of anticancer drugs to kill all the abnormal cells. This marrow is then frozen to save it. The marrow remaining in the patient's body is destroyed with high-dose chemotherapy and radiation therapy. The marrow that was frozen is then thawed and given back to the patient through a needle in a vein. This mode of bone marrow transplant is currently being investigated in clinical trials.

Biological therapy or immunotherapy is a mode of treatment in which the body's own immune system is harnessed to fight the cancer. Substances that are routinely made by the immune system (such as growth factors, hormones, and disease-fighting proteins) are either synthetically made in a laboratory or their effectiveness is boosted and they are then put back into the patient's body. This treatment mode is also being investigated in clinical trials all over the country at major cancer centers.

Prognosis

Like all cancers, the prognosis for leukemia depends on the patient's age and general health. According to statistics, more than 60% of the patients with leukemia survive for at least a year after diagnosis. Acute myelocytic leukemia (AML) has a poorer prognosis rate than acute lymphocytic leukemias (ALL) and the chronic leukemias. In the last 15 to 20 years, the five-year survival rate for patients with ALL has increased from 38% to 57%.

Interestingly enough, since most childhood leukemias are of the ALL type, chemotherapy has been highly successful in their treatment. This is because chemotherapeutic drugs are most effective against actively growing cells. Due to the new combinations of anticancer drugs being used, the survival rates among children with ALL have improved dramatically. Eighty percent of the children diagnosed with ALL now survive for five years or more, as compared to 50% in the late 1970s.

Prevention

Most cancers can be prevented by changes in lifestyle or diet, which will reduce the risk factors. However, in leukemias, there are no such known risk factors. Therefore, at the present time, no way is known to prevent leukemias from developing. People who are at an increased risk for developing leukemia because of proven exposure to ionizing radiation or exposure to the toxic liquid benzene, and people with Down syndrome, should undergo periodic medical checkups.

Resources

ORGANIZATIONS

American Cancer Society. 1599 Clifton Rd., NE, Atlanta, GA 30329-4251. (800) 227-2345. 〈http://www.cancer.org〉.

Cancer Research Institute. 681 Fifth Ave., New York, N.Y. 10022. (800) 992-2623. 〈http://www.cancerresearch.org〉.

Leukemia Society of America, Inc. 600 Third Ave., New York, NY 10016. (800) 955-4572. 〈http://www.leukemia.org〉.

National Cancer Institute. Building 31, Room 10A31, 31 Center Drive, MSC 2580, Bethesda, MD 20892-2580. (800) 422-6237. 〈http://www.nci.nih.gov〉.

Oncolink. University of Pennsylvania Cancer Center. 〈http://cancer.med.upenn.edu〉.

KEY TERMS

Antibodies— Proteins made by the B lymphocytes in response to the presence of infectious agents, such as bacteria or viruses, in the body.

Biopsy— The surgical removal and microscopic examination of living tissue for diagnostic purposes.

Chemotherapy— Treatment with drugs that act against cancer.

Computerized tomography (CT) scan— A series of x rays put together by a computer in order to form detailed pictures of areas inside the body.

Cytokines— Chemicals made by the cells that act on other cells to stimulate or inhibit their function. Cytokines that stimulate growth are called "growth factors."

Immunotherapy— Treatment of cancer by stimulating the body's immune defense system.

Lumbar puncture— A procedure in which the doctor inserts a small needle into the spinal cavity in the lower back to withdraw some spinal fluid for testing. Also known as a "spinal tap."

Magnetic resonance imaging (MRI)— A medical procedure using a magnet linked to a computer to picture areas inside the body.

Maturation— The process by which stem cells transform from immature cells without a specific function into a particular type of blood cell with defined functions.

Radiation therapy— Treatment using high-energy radiation from x-ray machines, cobalt, radium, or other sources.

Remission— A disappearance of a disease as a result of treatment. Complete remission means that all disease is gone. Partial remission means that the disease is significantly improved by treatment, but residual traces of the disease are still present.

Leukemias, Acute

Definition

Acute leukemia is a type of cancer in which excessive quantities of abnormal white blood cells are produced.

Description

Medical science classifies acute leukemia by the type of white blood cell that undergoes mutation. The most common of these are:

• Acute lymphoblastic leukemia (ALL), in which excessive quantities of lymphoblasts, or immature lymphocyte white blood cells, are produced.
• Acute myeloblastic leukemia (AML), also known as acute nonlymphocytic leukemia (ANLL), in which excessive quantities of other types of immature white blood cells are produced.

Acute leukemias progress rapidly, while the chronic leukemias progress more slowly. The vast majority of the childhood leukemias are of the acute form.

The cells that make up blood are produced in the bone marrow and the lymphatic system. Bone marrow is the spongy tissue found in the large bones of the body. The lymphatic system includes the spleen (an organ in the upper abdomen), the thymus (a small gland beneath the breastbone), and the tonsils (a mass of lymphatic tissue located in the throat). In addition, the lymphatic vessels (tiny tubes that branch like blood vessels into all parts of the body) and lymph nodes (pea-shaped organs that are found along the network of lymphatic vessels) are also part of the lymphatic system. Lymph is a milky fluid that contains cells. Clusters of lymph nodes are found in the neck, underarm, pelvis, abdomen, and chest.

The cells found in the blood include red blood cells (RBCs) that carry oxygen and other materials to all tissues of the body; white blood cells (WBCs) that fight infection; and platelets, which play an important role in the clotting of the blood. White blood cells can be further subdivided into three main types: granulocytes, monocytes, and lymphocytes.

The granulocytes, as their name suggests, have particles (granules) inside them. These granules contain special proteins (enzymes) and several other substances that can break down chemicals and destroy microorganisms, such as bacteria. Monocytes are the second type of white blood cell. They are also important in defending the body against pathogens.

Lymphocytes are the third type of white blood cell. There are two primary types of lymphocytes—T lymphocytes and B lymphocytes—with different functions in the immune system. B cells protect the body by making antibodies. Antibodies are proteins that can attach to the surfaces of bacteria and viruses. This "attachment" sends signals to many other cell types to come and destroy the antibody-coated organism. T cells protect the body against viruses. When a virus enters a cell, it produces certain proteins that are projected onto the surface of the infected cell. T cells recognize these proteins and make certain chemicals that are capable of destroying the virus-infected cells. In addition, T cells can destroy some types of cancer cells.

Bone marrow makes stem cells, which are the precursors of the different blood cells. These stem cells mature through stages into RBCs, WBCs, or platelets. In acute leukemias, the maturation process of the white blood cells is interrupted. The immature cells (or "blasts") proliferate rapidly and begin to accumulate in various organs and tissues, thereby affecting their normal function. This uncontrolled proliferation of the immature cells in the bone marrow affects the production of the normal red blood cells and platelets as well.

As noted, there are two types of acute leukemias—acute lymphocytic leukemia and acute myelogenous leukemia. Different types of white blood cells are involved in the two leukemias. In acute lymphocytic leukemia (ALL), it is the T or the B lymphocytes that are involved. The B cell leukemias are more common than T cell leukemias. Acute myelogenous leukemia, also known as acute nonlymphocytic leukemia (ANLL), is a cancer of the monocytes and/or granulocytes.

Leukemias account for 2% of all cancers. Because leukemia is the most common form of childhood cancer, it is often regarded as a disease of childhood. However, leukemias affect far more adults than children. Half of the cases occur in people who are 60 years of age or older. The incidence of acute and chronic leukemias is about the same. According to the estimates of the American Cancer Society (ACS), approximately 29,000 new cases of leukemia are diagnosed each year in the United States. Of these, 27,000 will be diagnosed in adults, 2,000 in children.

Causes and symptoms

Leukemia strikes both sexes and all ages. The human T-cell leukemia virus (HTLV-I), a virus with similarities to the human immunodeficiency virus (HIV), is believed to be the causative agent for some kinds of leukemias, but this has not yet been proven, and the cause of most leukemias is not known. Acute lymphoid leukemia (ALL) is more common among Caucasians than among African-Americans, while acute myeloid leukemia (AML) affects both races equally. The incidence of acute leukemia is slightly higher among men than women. People with Jewish ancestry have a higher likelihood of getting leukemia. A higher incidence of leukemia has also been observed among persons with Down syndrome and some other genetic abnormalities.

Reports in Science News cited studies that found a gene that regulates folic acid metabolism in the body to be more prevalent in acute lymphocytic leukemia (ALL) patients. Folic acid is known to be involved in the process of DNA maintenance and repair, and this gene diverts folic acid from this function. It is therefore hypothesized that this gene plays a role in the development of ALL, and that folic acid supplementation could lower the risk for developing ALL. This gene has not been found to play a part in other leukemias, such as AML.

Exposure to ionizing radiation, such as occurred in Japan after the atomic bomb explosions, has been shown to increase the risk of getting leukemia. Electromagnetic fields are suspected of being a possible cause, as are certain organic chemicals, such as benzene. Having a history of diseases that damage the bone marrow, such as aplastic anemia, or a history of cancers of the lymphatic system puts people at a high risk for developing acute leukemias. Similarly, the use of anticancer medications, immunosuppressants, and the antibiotic chloramphenicol are also considered risk factors for developing acute leukemias.

The symptoms of leukemia are generally vague and non-specific. A patient may experience all or some of the following symptoms:

• weakness or chronic fatigue
• fever of unknown origin, chills and flu-like symptoms
• weight loss that is not due to dieting or exercise
• frequent bacterial or viral infections
• headaches
• skin rash
• non-specific bone pain
• easy bruising
• bleeding from gums or nose
• blood in urine or stools
• swollen and tender lymph nodes and/or spleen
• abdominal fullness
• night sweats
• petechiae, or tiny red spots under the skin
• more rarely, sores in the eyes or on the skin

Diagnosis

For a successful outcome, treatment for acute leukemia must begin as soon as possible, but there are no screening tests available. If the doctor has reason to suspect leukemia, he or she will conduct a very thorough physical examination to look for enlarged lymph nodes in the neck, underarm, and pelvic region. Swollen gums, enlarged liver or spleen, bruises, or pinpoint red rashes all over the body are some of the signs of leukemia. Urine and blood tests may be ordered to check for microscopic amounts of blood in the urine and to obtain a complete differential blood count. This count will give the numbers and percentages of the different cells found in the blood. An abnormal blood test might suggest leukemia; however, the diagnosis must be confirmed by more specific tests.

The doctor may perform a bone marrow biopsy to confirm the diagnosis of leukemia. During the biopsy, a cylindrical piece of bone and marrow is removed. The tissue is generally taken out of the hipbone. These samples are sent to the laboratory where they are examined under a microscope by a hematologist, oncologist, or pathologist. In addition to the diagnostic biopsy, another biopsy will also be performed during the treatment phase of the disease to see if the leukemia is responding to therapy.

A spinal tap (lumbar puncture) is another procedure that the doctor may order to diagnose leukemia. In this procedure, a small needle is inserted into the spinal cavity in the lower back to withdraw some cerebrospinal fluid and to look for leukemic cells.

Standard imaging tests, such as x rays, computed tomography scans (CT scans ), and magnetic resonance imaging (MRI) may be used to check whether the leukemic cells have invaded other areas of the body, such as the bones, chest, kidneys, abdomen, or brain. A gallium scan or bone scan is a test in which a radioactive chemical is injected into the body. This chemical accumulates in the areas of cancer or infection, allowing them to be viewed with a special camera.

Treatment

As noted, treatment must be begun as soon as possible. The goal of treatment is remission, or an arresting of the disease process of the leukemia. There are two phases of treatment for leukemia. The first phase is called induction therapy. As the name suggests, during this phase, the primary aim of the treatment is to reduce the number of leukemic cells as much as possible and induce a remission in the patient. Once the patient shows no obvious signs of leukemia (no leukemic cells are detected in blood tests and bone marrow biopsies), the patient is said to be in remission.

The second phase of treatment is then initiated. This is called continuation or maintenance therapy, and the goal is to kill any remaining cancer cells and to maintain the remission for as long as possible.

Chemotherapy

Chemotherapy is the use of drugs to kill cancer cells. It is usually the treatment of choice in leukemia, and is used to relieve symptoms and achieve long-term remission of the disease. Generally, combination chemotherapy, in which multiple drugs are used, is more efficient than using a single drug for the treatment. Some drugs may be administered intravenously through a vein in the arm; others may be given by mouth in the form of pills. If the cancer cells have invaded the brain, then chemotherapeutic drugs may be put into the fluid that surrounds the brain through a needle in the brain or back. This is known as intrathecal chemotherapy. Because leukemia cells can spread to all the organs via the blood stream and the lymphatic vessels, surgery is not considered an option for treating leukemias.

In 2005, the U.S. Food and Drug Administration (FDA) approved clofarabine (Clolar) for the treatment of children with refractory or relapsed acute lymphoblastic leukemia (ALL). Clofarabine is the first new leukemia treatment approved specifically for children in more than a decade. Clofarabine is indicated for the treatment of pediatric patients ages one to 21 years with relapsed or refractory ALL after at least two prior regimens. The most common adverse effects after clofarabine treatment, regardless of causality, were gastrointestinal tract symptoms, including vomiting, nausea, and diarrhea; hematologic effects, including anemia, leucopenia, thrombocytopenia, neutropenia, and febrile neutropenia; and infection. Careful hematologic monitoring during therapy is important.

Radiation

Radiation therapy, which involves the use of x rays or other high-energy rays to kill cancer cells and shrink tumors, may be used in some cases. For acute leukemias, the source of radiation is usually outside the body (external radiation therapy). If the leukemic cells have spread to the brain, radiation therapy can be given to the brain.

Bone marrow transplantation

Bone marrow transplantation is a process in which the patient's diseased bone marrow is replaced with healthy marrow. There are two ways of doing a bone marrow transplant. In an allogeneic bone marrow transplant, healthy marrow is taken from a donor whose tissue is either the same as or very closely resembles the patient's tissues. The donor may be a twin, a brother or sister (sibling), or a person who is not related at all. First, the patient's bone marrow is destroyed with very high doses of chemotherapy and radiation therapy. Healthy marrow from the donor is then given to the patient through a needle in a vein to replace the destroyed marrow.

In the second type of bone marrow transplant, called an autologous bone marrow transplant, some of the patient's own marrow is taken out and treated with a combination of anticancer drugs to kill all the abnormal cells. This marrow is then frozen to preserve it. The marrow remaining in the patient's body is destroyed with high-dose chemotherapy and radiation therapy. The marrow that was frozen is then thawed and given back to the patient through a needle in a vein. This type of bone marrow transplant is currently being investigated in clinical trials.

Biological therapy or immunotherapy is a mode of treatment in which the body's own immune system is harnessed to fight the cancer. Interferon is a biological therapy that is increasingly being used. Substances that are routinely made by the immune system (such as growth factors, hormones, and disease-fighting proteins) are either synthetically made in a laboratory or their effectiveness is boosted and they are then put back into the patient's body. This treatment mode is also being investigated in clinical trials all over the country at major cancer centers.

Prognosis

Like all cancers, the prognosis for leukemia depends on the patient's age and general health. According to statistics, more than 60% of the patients with leukemia survive for at least a year after diagnosis. Acute myelocytic leukemia (AML) has a poorer prognosis rate than acute lymphocytic leukemias (ALL) and the chronic leukemias. In the last 20 years, the five-year survival rate for patients with ALL has increased from 38% to 57%.

Interestingly enough, since most childhood leukemias are of the ALL type, chemotherapy has been highly successful in their treatment. This is because chemotherapeutic drugs are most effective against actively growing cells. Due to the new combinations of anticancer drugs being used, the survival rates among children with ALL have improved dramatically. Ninety-five percent of all childhood ALL patients will enter remission, and 60-75% will remain in remission after five years, depending upon the type. T-cell ALL is considered curable in half of all cases, while B-cell ALL is rarely, if ever curable. The worst prognosis is for non-typable ALL, whose victims are usually below one year of age.

Health care team roles

In most cases, a diagnosis of leukemia is made in a physician's office, a general medical clinic, or emergency room by a primary care practitioner. Children and adolescents with leukemia are likely to be diagnosed by their primary care physician, or pediatrician. However, oncologists, or physicians that specialize in the diagnosis and treatment of cancer are also often involved. Hematologists, physicians that specialize in the diagnosis and treatment of disorders of the blood and the organs that produce blood cells, may become involved through consultation. A pathologist, or physician who specializes in studying tissue and cell samples, often to assist other physicians in reaching the correct diagnosis, also may be consulted.

KEY TERMS

Antibodies— Proteins made by the B lymphocytes in response to the presence in the body of infectious agents, such as bacteria or viruses.

Biopsy— The surgical removal and microscopic examination of living tissue for diagnostic purposes.

Chemotherapy— Treatment with drugs that act against cancer.

Computerized tomography (CT) scan— A series of x rays put together by a computer in order to form detailed pictures of areas inside the body.

Cytokines— Chemicals made by the cells that act on other cells to stimulate or inhibit their function. Cytokines that stimulate growth are called growth factors.

Immunotherapy— Treatment of cancer by stimulating the body's immune defense system.

Lumbar puncture— A procedure in which the doctor inserts a small needle into the spinal cavity in the lower back to withdraw some spinal fluid for testing. Also known as a spinal tap.

Magnetic resonance imaging (MRI)— A medical procedure using a magnet linked to a computer to picture areas inside the body.

Maturation— The process by which stem cells transform from immature cells without a specific function into a particular type of blood cell with defined functions.

Radiation therapy— Treatment using high-energy radiation from x-ray machines, cobalt, radium, or other sources.

Remission— A disappearance of a disease as a result of treatment. Complete remission means that all disease is gone. Partial remission means that the disease is significantly improved by treatment, but residual traces of the disease are still present.

Both registered nurses and licensed practical nurses provide direct care to leukemia patients in general hospitals, homes, or other healthcare facilities. Good supportive nursing care and observation are necessary to:

• Prevent or monitor for the infections to which leukemia patients are so susceptible.
• Monitor for anemia and bleeding.
• Assist in treatments such as chemotherapy, radiation, bone-marrow transplantation, or in giving blood transfusions.
• Monitor vital signs.
• Provide teaching regarding the prevention of infection, the normal course of leukemia, including the fatigue so many patients feel, the signs and symptoms of anemia, and good dental care (both leukemia and chemotherapy are apt to cause sensitivity in the mouth, vulnerability to infection and bleeding).

Clinical laboratory scientists draw blood samples that are ordered by the physician to monitor the leukemia from the outset, during treatment, and also during remission. Radiologic technologists take x rays to visualize and monitor parts of the body that may be affected by the leukemia.

Prevention

Most cancers can be prevented by changes in lifestyle or diet, which will reduce the risk factors. However, in leukemias, there are no such known risk factors. Therefore, at the present time, no way is known to prevent leukemias from developing. People who are at an increased risk for developing leukemia because of proven exposure to ionizing radiation or exposure to the toxic liquid benzene, and people with Down syndrome, should undergo periodic medical checkups.

Resources

BOOKS

Hiddemann, Wolfgang, et al.Acute Leukemias IX New York: Springer, 2003.

Icon Health Publications Acute Leukemia—A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References San Diego: Icon Health Publications, 2004.

Parker, James N., and Philip M. Parker The Official Parent's Sourcebook on Childhood Acute Lymphoblastic Leukemia San Diego: Icon Health Publications, 2002.

Pui, Ching-Hong Treatment of Acute Leukemias: New Directions for Clinical Research Totowa, NJ: Humana Press, 2003.

PERIODICALS

Bauer, Jeff. "Intensive Leukemia Treatment Equalizes Survival Rates for Black and White Children." RN (January 2004): 18.

Hill, Garick, et al. "Recent Steroid Therapy Increases Severity of Varicella Infections in Children with Acute Lymphoblastic Leukemia." Pediatrics (October 2005): 1010-1011.

Kirn, Timothy F. "ALL Gene Predicts Children's Response to Chemotherapy: Chance of Long-Term Remission: 87%." Family Practice News (May 15, 2004): 58.

Lilleyman, John. "Simple Deliverable Therapy Needed for Childhood Leukemia." The Lancet (Aug. 30, 2003): 676.

LoBuono, Charlotte. "First Leukemia Drug in 10 Years Cleared for Kids." Drug Topics (Feb. 7, 2005): 52.

Mohn, Angelika, et al. "Persistence of Impaired Pancreatic B-Cell Function in Children Treated for Acute Lymphoblastic Leukemia." The Lancet (Jan. 10, 2004): 127.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Road, N.E., Atlanta, Georgia 30329. (800) 227-2345. 〈http://www.cancer.org〉.

Cancer Research Institute. 681 Fifth Avenue, New York, N.Y. 10022. (800) 992-2623. 〈http://www.cancerresearch.org〉.

The Leukemia & Lymphoma Society. 1311 Mamaroneck Ave., White Plains, NY 10605. (914) 949-5213. www.leukemia-lymphoma.org

Leukemia Society of America, Inc. 600 Third Avenue, New York, NY 10016. (800) 955-4572. 〈http://www.leukemia.org〉.

OTHER

University of Pennsylvania Cancer Center. Oncolink. 〈http://cancer.med.upenn.edu〉.

Leukemias, acute

Definition

Acute leukemia is a type of cancer in which excessive quantities of abnormal white blood cells are produced.

Description

Medical science further classifies acute leukemia by the type of white blood cell that undergoes mutation. The most common of these are:

• Acute lymphoblastic leukemia (ALL), in which excessive quantities of lymphoblasts, or immature lymphocyte white blood cells, are produced.
• Acute myeloblastic leukemia (AML), also known as acute nonlymphocytic leukemia (ANLL), in which excessive quantities of other types of immature white blood cells are produced.

Acute leukemias progress rapidly, while the chronic leukemias progress more slowly. The vast majority of the childhood leukemias are of the acute form.

The cells that make up blood are produced in the bone marrow and the lymphatic system . Bone marrow is the spongy tissue found in the large bones of the body. The lymphatic system includes the spleen (an organ in the upper abdomen), the thymus (a small gland beneath the breastbone), and the tonsils (a mass of lymphatic tissue located in the throat). In addition, the lymphatic vessels (tiny tubes that branch like blood vessels into all parts of the body) and lymph nodes (pea-shaped organs that are found along the network of lymphatic vessels) are also part of the lymphatic system. Lymph is a milky fluid that contains cells. Clusters of lymph nodes are found in the neck, underarm, pelvis, abdomen, and chest.

The cells found in the blood include red blood cells (RBCs) that carry oxygen and other materials to all tissues of the body; white blood cells (WBCs) that fight infection ; and platelets, which play an important role in the clotting of the blood. White blood cells can be further subdivided into three main types: granulocytes, monocytes, and lymphocytes.

The granulocytes, as their name suggests, have particles (granules) inside them. These granules contain special proteins (enzymes) and several other substances that can break down chemicals and destroy microorganisms, such as bacteria . Monocytes are the second type of white blood cell. They are also important in defending the body against pathogens.

Lymphocytes are the third type of white blood cell. There are two primary types of lymphocytes—T lymphocytes and B lymphocytes—with different functions in the immune system . B cells protect the body by making antibodies. Antibodies are proteins that can attach to the surfaces of bacteria and viruses . This "attachment" sends signals to many other cell types to come and destroy the antibody-coated organism. T cells protect the body against viruses. When a virus enters a cell, it produces certain proteins that are projected onto the surface of the infected cell. T cells recognize these proteins and make certain chemicals that are capable of destroying the virus-infected cells. In addition, T cells can destroy some types of cancer cells.

Bone marrow makes stem cells, which are the precursors of the different blood cells. These stem cells mature through stages into either RBCs, WBCs, or platelets. In acute leukemias, the maturation process of the white blood cells is interrupted. The immature cells (or "blasts") proliferate rapidly and begin to accumulate in various organs and tissues, thereby affecting their normal function. This uncontrolled proliferation of the immature cells in the bone marrow affects the production of the normal red blood cells and platelets as well.

As noted, there are two types of acute leukemias—acute lymphocytic leukemia and acute myelogenous leukemia. Different types of white blood cells are involved in the two leukemias. In acute lymphocytic leukemia (ALL), it is the T or the B lymphocytes that are involved. The B cell leukemias are more common than T cell leukemias. Acute myelogenous leukemia, also known as acute nonlymphocytic leukemia (ANLL), is a cancer of the monocytes and/or granulocytes.

Leukemias account for 2% of all cancers. Because leukemia is the most common form of childhood cancer, it is often regarded as a disease of childhood. However, leukemias affect far more adults than children. Half of the cases occur in people who are 60 years of age or older. The incidence of acute and chronic leukemias is about the same. According to the estimates of the American Cancer Society (ACS), approximately 29,000 new cases of leukemia are diagnosed each year in the United States. Of these, 27,000 will be diagnosed in adults, 2,000 in children.

Causes and symptoms

Leukemia strikes both sexes and all ages. The human T-cell leukemia virus (HTLV-I), a virus with similarities to the human immunodeficiency virus (HIV), is believed to be the causative agent for some kinds of leukemias, but this has not yet been proven, and the cause of most leukemias is not known. Acute lymphoid leukemia (ALL) is more common among Caucasians than among African-Americans, while acute myeloid leukemia (AML) affects both races equally. The incidence of acute leukemia is slightly higher among men than women. People with Jewish ancestry have a higher likelihood of getting leukemia. A higher incidence of leukemia has also been observed among persons with Down syndrome and some other genetic abnormalities.

Reports in Science News cited studies that found a gene that regulates folic acid metabolism in the body to be more prevalent in acute lymphocytic leukemia (ALL) patients. Folic acid is known to be involved in the process of DNA maintenance and repair, and this gene diverts folic acid from this function. It is therefore hypothesized that this gene plays a role in the development of ALL, and that folic acid supplementation could lower the risk for developing ALL. This gene has not been found to play a part in other leukemias, such as AML.

Exposure to ionizing radiation, such as occurred in Japan after the atomic bomb explosions, has been shown to increase the risk of getting leukemia. Electromagnetic fields are suspected of being a possible cause, as are certain organic chemicals, such as benzene. Having a history of diseases that damage the bone marrow, such as aplastic anemia, or a history of cancers of the lymphatic system puts people at a high risk for developing acute leukemias. Similarly, the use of anticancer medications, immunosuppressants, and the antibiotic chloramphenicol are also considered risk factors for developing acute leukemias.

The symptoms of leukemia are generally vague and non-specific. A patient may experience all or some of the following symptoms:

• weakness or chronic fatigue
• fever of unknown origin, chills and flu-like symptoms
• weight loss that is not due to dieting or exercise
• frequent bacterial or viral infections
• headaches
• skin rash
• non-specific bone pain
• easy bruising
• bleeding from gums or nose
• blood in urine or stools
• swollen and tender lymph nodes and/or spleen
• abdominal fullness
• night sweats
• petechiae, or tiny red spots under the skin
• more rarely, sores in the eyes or on the skin

Diagnosis

For a successful outcome, treatment for acute leukemia must begin as soon as possible, but there are no screening tests available. If the doctor has reason to suspect leukemia, he or she will conduct a very thorough physical examination to look for enlarged lymph nodes in the neck, underarm, and pelvic region. Swollen gums, enlarged liver or spleen, bruises, or pinpoint red rashes all over the body are some of the signs of leukemia. Urine and blood tests may be ordered to check for microscopic amounts of blood in the urine and to obtain a complete differential blood count. This count will give the numbers and percentages of the different cells found in the blood. An abnormal blood test might suggest leukemia; however, the diagnosis must be confirmed by more specific tests.

The doctor may perform a bone marrow biopsy to confirm the diagnosis of leukemia. During the biopsy, a cylindrical piece of bone and marrow is removed. The tissue is generally taken out of the hipbone. These samples are sent to the laboratory where they are examined under a microscope by a hematologist, oncologist, or pathologist. In addition to the diagnostic biopsy, another biopsy will also be performed during the treatment phase of the disease to see if the leukemia is responding to therapy.

A spinal tap (lumbar puncture) is another procedure that the doctor may order to diagnose leukemia. In this procedure, a small needle is inserted into the spinal cavity in the lower back to withdraw some cerebrospinal fluid and to look for leukemic cells.

Standard imaging tests, such as x rays, computed tomography scans (CT scans ), and magnetic resonance imaging (MRI) may be used to check whether the leukemic cells have invaded other areas of the body, such as the bones, chest, kidneys , abdomen, or brain . A gallium scan or bone scan is a test in which a radioactive chemical is injected into the body. This chemical accumulates in the areas of cancer or infection, allowing them to be viewed with a special camera.

Treatment

As noted, treatment must be begun as soon as possible. The goal of treatment is remission, or an arresting of the disease process of the leukemia. There are two phases of treatment for leukemia. The first phase is called induction therapy. As the name suggests, during this phase, the primary aim of the treatment is to reduce the number of leukemic cells as much as possible and induce a remission in the patient. Once the patient shows no obvious signs of leukemia (no leukemic cells are detected in blood tests and bone marrow biopsies), the patient is said to be in remission.

The second phase of treatment is then initiated. This is called continuation or maintenance therapy, and the goal is to kill any remaining cancer cells and to maintain the remission for as long as possible.

Chemotherapy

Chemotherapy is the use of drugs to kill cancer cells. It is usually the treatment of choice in leukemia, and is used to relieve symptoms and achieve long-term remission of the disease. Generally, combination chemotherapy, in which multiple drugs are used, is more efficient than using a single drug for the treatment. Some drugs may be administered intravenously through a vein in the arm; others may be given by mouth in the form of pills. If the cancer cells have invaded the brain, then chemotherapeutic drugs may be put into the fluid that surrounds the brain through a needle in the brain or back.

This is known as intrathecal chemotherapy. Because leukemia cells can spread to all the organs via the blood stream and the lymphatic vessels, surgery is not considered an option for treating leukemias.

Radiation

Radiation therapy, which involves the use of x rays or other high-energy rays to kill cancer cells and shrink tumors, may be used in some cases. For acute leukemias, the source of radiation is usually outside the body (external radiation therapy). If the leukemic cells have spread to the brain, radiation therapy can be given to the brain.

Bone marrow transplantation

Bone marrow transplantation is a process in which the patient's diseased bone marrow is replaced with healthy marrow. There are two ways of doing a bone marrow transplant. In an allogeneic bone marrow transplant, healthy marrow is taken from a donor whose tissue is either the same as or very closely resembles the patient's tissues. The donor may be a twin, a brother or sister (sibling), or a person who is not related at all. First, the patient's bone marrow is destroyed with very high doses of chemotherapy and radiation therapy. Healthy marrow from the donor is then given to the patient through a needle in a vein to replace the destroyed marrow.

KEY TERMS

Antibodies —Proteins made by the B lymphocytes in response to the presence in the body of infectious agents, such as bacteria or viruses.

Biopsy —The surgical removal and microscopic examination of living tissue for diagnostic purposes.

Chemotherapy —Treatment with drugs that act against cancer.

Computerized tomography (CT) scan —A series of x rays put together by a computer in order to form detailed pictures of areas inside the body.

Cytokines —Chemicals made by the cells that act on other cells to stimulate or inhibit their function. Cytokines that stimulate growth are called growth factors.

Immunotherapy —Treatment of cancer by stimulating the body's immune defense system.

Lumbar puncture —A procedure in which the doctor inserts a small needle into the spinal cavity in the lower back to withdraw some spinal fluid for testing. Also known as a spinal tap.

Magnetic resonance imaging (MRI) —A medical procedure using a magnet linked to a computer to picture areas inside the body.

Maturation —The process by which stem cells transform from immature cells without a specific function into a particular type of blood cell with defined functions.

Radiation therapy —Treatment using high-energy radiation from x-ray machines, cobalt, radium, or other sources.

Remission —A disappearance of a disease as a result of treatment. Complete remission means that all disease is gone. Partial remission means that the disease is significantly improved by treatment, but residual traces of the disease are still present.

In the second type of bone marrow transplant, called an autologous bone marrow transplant, some of the patient's own marrow is taken out and treated with a combination of anticancer drugs to kill all the abnormal cells. This marrow is then frozen to preserve it. The marrow remaining in the patient's body is destroyed with high-dose chemotherapy and radiation therapy. The marrow that was frozen is then thawed and given back to the patient through a needle in a vein. This type of bone marrow transplant is currently being investigated in clinical trials.

Biological therapy or immunotherapy is a mode of treatment in which the body's own immune system is harnessed to fight the cancer. Interferon is a biological therapy that is increasingly being used. Substances that are routinely made by the immune system (such as growth factors, hormones, and disease-fighting proteins) are either synthetically made in a laboratory or their effectiveness is boosted and they are then put back into the patient's body. This treatment mode is also being investigated in clinical trials all over the country at major cancer centers.

Prognosis

Like all cancers, the prognosis for leukemia depends on the patient's age and general health. According to statistics, more than 60% of the patients with leukemia survive for at least a year after diagnosis. Acute myelocytic leukemia (AML) has a poorer prognosis rate than acute lymphocytic leukemias (ALL) and the chronic leukemias. In the last 15 to 20 years, the five-year survival rate for patients with ALL has increased from 38% to 57%.

Interestingly enough, since most childhood leukemias are of the ALL type, chemotherapy has been highly successful in their treatment. This is because chemotherapeutic drugs are most effective against actively growing cells. Due to the new combinations of anti-cancer drugs being used, the survival rates among children with ALL have improved dramatically. Ninety-five percent of all childhood ALL patients will enter remission, and 60–75% will remain in remission after five years, depending upon the type. T-cell ALL is considered cureable in half of all cases, while B-cell ALL is rarely, if ever cureable. The worst prognosis is for non-typable ALL, whose victims are usually below one year of age.

Health care team roles

In most cases, a diagnosis of leukemia is made in a physician's office, a general medical clinic, or emergency room by a primary care practitioner. Children and adolescents with leukemia are likely to be diagnosed by their primary care physician, or pediatrician. However, oncologists, or physicians that specialize in the diagnosis and treatment of cancer are also often involved. Hematologists, physicians that specialize in the diagnosis and treatment of disorders of the blood and the organs that produce blood cells, may become involved through consultation. A pathologist, or physician who specializes in studying tissue and cell samples, often to assist other physicians in reaching the correct diagnosis, also may be consulted.

Both registered nurses and licensed practical nurses provide direct care to leukemia patients in general hospitals, homes, or other healthcare facilities. Good supportive nursing care and observation are necessary to:

• Prevent or monitor for the infections to which leukemia patients are so susceptible.
• Monitor for anemia and bleeding.
• Assist in treatments such as chemotherapy, radiation, bone-marrow transplantation, or in giving blood transfusions.
• Monitor vital signs.
• Provide teaching regarding the prevention of infection, the normal course of leukemia, including the fatigue so many patients feel, the signs and symptoms of anemia, and good dental care (both leukemia and chemotherapy are apt to cause sensitivity in the mouth, vulnerability to infection and bleeding).

Clinical laboratory scientists draw blood samples that are ordered by the physician to monitor the leukemia from the outset, during treatment, and also during remission. Radiologic technologists take x rays to visualize and monitor parts of the body that may be affected by the leukemia.

Prevention

Most cancers can be prevented by changes in lifestyle or diet, which will reduce the risk factors. However, in leukemias, there are no such known risk factors. Therefore, at the present time, no way is known to prevent leukemias from developing. People who are at an increased risk for developing leukemia because of proven exposure to ionizing radiation or exposure to the toxic liquid benzene, and people with Down syndrome, should undergo periodic medical checkups.

Resources

BOOKS

Beers, Mark H., et al., eds. Merck Manual of Diagnosis and Therapy. 17th ed. Rahway, NJ: Merck & Co., 1999.

Keene, Nancy, and Linda Lamb, eds. Childhood Leukemia: A Guide for Families, Friends and Caregivers. Cambridge, MA: O'Reilly & Associates, 1999.

Lackritz, Barbara. Adult Leukemia: A Comprehensive Guide for Patients and Families. Cambridge, MA: O'Reilly & Associates, 2001.

Murphy, Gerald P. Informed Decisions: The Complete Book of Cancer Diagnosis, Treatment and Recovery. Atlanta, GA: American Cancer Society, 1997.

PERIODICALS

Seppa, N. "Genetic Variants May Ease Leukemia Risk." Science News 156 (November 6,1999): 293.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Road, N.E., Atlanta, Georgia 30329. (800) 227-2345. <http://www.cancer.org>.

Cancer Research Institute. 681 Fifth Avenue, New York, N.Y. 10022. (800) 992-2623. <http://www.cancerresearch.org>.

National Cancer Institute. 9000 Rockville Pike, Building 31, Room 10A16, Bethesda, Maryland, 20892. (800) 422-6237. <http://wwwicic.nci.nih.gov>.

Leukemia Society of America, Inc. 600 Third Avenue, New York, NY 10016. (800) 955-4572. <http://www.leukemia.org>.

OTHER

University of Pennsylvania Cancer Center. Oncolink. <http://cancer.med.upenn.edu>.

Joan M. Schonbeck

Leukemia

Sam’s Story

What Is Leukemia?

What Causes Leukemia?

What Are the Symptoms of Leukemia?

How Is Leukemia Diagnosed?

How Is Leukemia Treated?

Living with Leukemia

Resources

Leukemia (loo-KEY-me-a) is a type of cancer in which the body produces a large number of immature, abnormally shaped blood cells. It usually affects the white blood cells, or leukocytes (LOO-ko-sites), which help the body fight infections and other diseases.

KEYWORDS

for searching the Internet and other reference sources

Acute lymphocytic leukemia

Bone marrow transplantation

Neoplasms

Oncology

Leukemia

Sam’s Story

Sam had been looking forward to the basketball season for weeks. Now that it had actually started, though, he was having trouble keeping up during practice and in games. He just did not have the energy that he usually had, and he felt pain in his joints like never before. He found that he always needed to ask the coach to give him breaks during games. His teammates accused him of being out of shape, but Sam knew that it was more than that. His mother noticed that, even though he was playing less, he had more bruises than he did last season. Eventually, Sam was forced to sit out for a few weeks with a bad case of what appeared to be the flu. He felt constantly weak and tired, and he kept getting fevers. His mother decided that it was time to see the doctor and figure out what was going on.

After hearing about Sam’s symptoms, the doctor ran some blood tests. These showed that Sam had leukemia, and further testing indicated that it was a type called acute lymphocytic (lim-fo-SIT-ik) leukemia, or ALL. This is the most common type of leukemia in children.

Overall, leukemia accounts for about one third of cancer cases in children. However, like most other types of cancer, it is much more common in adults. Each year, roughly 27,000 adults and 2,000 children in the United States are diagnosed with leukemia.

What Is Leukemia?

Leukemia is a type of cancer that affects the bone marrow, the soft, spongy center of the bone that produces blood cells. White blood cells, or leukocytes, help the body fight infections and other diseases. Red blood cells, or erythrocytes (e-RITH-ro-sites), carry oxygen from the lungs to the body’s tissues and take carbon dioxide from the tissues back to the lungs. Platelets help form blood clots that control bleeding.

These cells are normally produced in an orderly, controlled way as the body needs them, but with leukemia, the process gets out of control. In most cases, the marrow produces too many immature white blood cells (called blasts), that are abnormally shaped and cannot carry out their usual duties. This explains why the disease is called “leukemia,” which literally means “white blood.” As these blasts multiply and crowd the bone marrow, they interfere with the production of other types of blood cells. When the blasts move into the body, they can collect in different places, causing swelling or pain.

Different types of leukemia are described according to how quickly the disease develops and what type of blood cell is affected:

• Acute (a-KUTE) leukemia gets worse quickly, with fast multiplication of abnormal, immature blasts.
• Chronic (KRON-ik) leukemia worsens gradually. Abnormal blasts are present, but they are more mature and can carry out some of their functions.
• Lymphocytic leukemia affects certain white blood cells called lymphocytes (LIM-fo-sites), which control the body’s immune response by finding and destroying foreign substances.
• Myelogenous (my-e-LOJ-e-nus) leukemia affects other types of white blood cells in the bone marrow.

Understanding Leukemia Lingo

Many of the terms associated with leukemia, including the name of the disease itself, are derived from the Greek language. Breaking down the words into their Greek roots makes them easier to understand.

• Leuk- or leuko- means white or colorless and is used to form the words “leukemia” and “leukocyte.”
• -ernia means blood and is found in the words “leukemia” and “anemia.”
• -cyte means cell and is used to form the words “leukocyte,” “erythrocyte,” and “lymphocyte.”
• Erythr- or erythro- means red. “Erythrocytes” are red blood cells.
• Chron- or chrono- means time. “Chronic” leukemia develops over a long period of time.

In all, there are four main forms of the disease: acute lymphocytic leukemia (ALL), acute myelogenous leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myelogenous leukemia (CML). Another less common form is called hairy cell leukemia, a chronic condition in which the cells develop projections that look like tiny hairs.

What Causes Leukemia?

In most cases of leukemia, doctors cannot pinpoint a specific cause. However, researchers have identified a few possible risk factors*. Studies have shown that people who are exposed to high or repeated doses of radiation*, such as Japanese survivors of the atomic bomb dropped at Hiroshima, and people with other types of cancer who have been treated with radiation therapy*, are more likely to develop leukemia. Workers who are exposed to certain chemicals, such as the benzene found in gasoline, also develop leukemia more frequently. In addition, certain viruses may play a role in the disease, although this is still under investigation.

* risk factors

are anything that increases the chance of developing a disease.

* radiation

is energy that is transmitted in the form of rays, waves, or particles. Only high-energy radiation, such as that found in x-rays and the sun’s ultraviolet rays, has been proven to cause human cancer.

* radiation therapy

is a treatment that uses high-energy radiation from x-rays and other sources to kill cancer cells and shrink cancerous growths.

Researchers also are studying how a persons genes* may be involved in causing leukemia. In studying the cells of people who have the disease, researchers have found that they often share certain genetic abnormalities.

* genes

are chemicals in the body that help determine a person’s characteristics, such as hair or eye color. They are inherited from a person’s parents and are contained in the chromosomes found in the cells of the body.

Some people have suggested a possible connection between childhood leukemia and the low-energy waves given off by high-voltage electric power lines. However, recent studies have not shown a relationship.

What Are the Symptoms of Leukemia?

When someone has leukemia, the abnormal, immature white blood cells that form cannot help the body fight off infections. As a result, the person may have frequent infections and develop flu-like symptoms, such as fever and chills. As these cells keep multiplying and move out into the body, they tend to collect in the lymph nodes* or in organs such as the liver* or spleen*. This may cause pain and swelling. If the cells collect in the central nervous system (the brain and spinal cord), they may cause headaches, vomiting, confusion, loss of muscle control, or seizures.

* lymph nodes

are round masses of tissue that contain immune cells that filter out harmful microorganisms.

* liver

is a large organ located in the upper abdomen that cleanses the blood and aids in digestion by secreting a substance called bile.

* spleen

is an organ near the stomach that helps the body fight infections and use red blood cells effectively.

The oversupply of white blood cells also interferes with the normal production of red blood cells and platelets, causing bleeding problems and a disorder called anemia (a-NEE-me-a). The person may look pale or feel weak and tired. They also may bleed or bruise easily, or find that their gums are swollen or bleeding. Other possible symptoms of leukemia include loss of appetite and/or weight; tiny red spots under the skin; sweating, especially at night; and bone or joint pain.

How Is Leukemia Diagnosed?

Doctors who see patients with these symptoms usually start by doing a full physical exam and feeling for swelling in the liver, the spleen, and the lymph nodes under the arms, in the groin, and in the neck. They also may take a sample of blood and examine it under a microscope to see what the cells look like and to determine the number of mature cells versus immature cells. Although blood tests may reveal that a patient has leukemia, they may not show what type it is. Another test called bone marrow aspiration may be necessary to check further for leukemia cells or to tell what type of leukemia a patient has. In this test, the doctor inserts a needle into a large bone, usually the hip, and removes a small sample of bone marrow. The sample then is examined under a microscope for leukemia cells.

If leukemia is present, the doctor may order additional tests to look for abnormal cells in other parts of the body. A spinal tap involves taking a sample of the fluid that fills the spaces in and around the brain and spinal cord, so that it can be checked for leukemia cells. Chest x-rays and special scans can reveal signs of the disease elsewhere in the body.

How Is Leukemia Treated?

Once acute leukemia is diagnosed, doctors start treating it right away, because it tends to worsen quickly. The goal is to bring about a complete remission, which means that there is no evidence of leukemia in the bone marrow or blood. Then doctors can give further treatment to help prevent a relapse, which means a return of the signs and symptoms of the disease after a period of improvement. Many people with acute forms of leukemia can be cured today. Just a few decades ago, ALL was considered incurable, but now it is one of the most curable forms of cancer.

Chronic leukemia sometimes is detected through a routine blood test before symptoms appear. People with chronic leukemia may not need treatment right away if they are not having symptoms yet. Doctors monitor the disease until treatment is needed. It usually can not be cured, but it can be controlled.

Chemotherapy

The most common treatments for leukemia are chemotherapy (kee-mo-THER-a-pee), radiation therapy, and/or bone marrow transplantation. In chemotherapy, patients take one or more anticancer drugs by mouth or intravenously, through a tube in one of the veins. In certain cases, doctors need to inject the drugs directly into the fluid that surrounds the brain and spinal cord. Chemotherapy can cause side effects, such as hair loss, nausea, fatigue, or easy bruising, depending on the drugs used. Most side effects go away gradually between treatments or after treatment stops.

Radiation therapy

In radiation therapy, doctors use a special machine to deliver high-energy rays that damage cancer cells and stop them from growing. The rays may be directed to one specific area of the body where leukemia cells have collected, such as the spleen, or to the whole body. Like chemotherapy, radiation therapy can cause temporary side effects, such as fatigue, hair loss, nausea, or red, dry, itchy skin.

Bone marrow transplantation

In bone marrow transplantation, doctors give high doses of chemotherapy and radiation to destroy all of the patient’s bone marrow, in order to kill the cells that are the source of the cancer. Then they give the patient healthy bone marrow from a donor whose tissue is similar, ideally from an identical twin or sibling. They also might give bone marrow that was removed from the patient earlier and specially treated to remove any leukemia cells. A patient who has a bone marrow transplant usually stays in the hospital for several weeks. The risk of infection is high until the transplanted bone marrow begins to produce enough white blood cells.

Biological therapy

The newest form of treatment under investigation is called biological therapy, which uses substances produced by the body to increase its ability to fight off leukemia. Scientists have identified several substances that are involved in the immune response, which is the body’s way of protecting itself from infections and other diseases. Today scientists can produce some of these substances in the lab and use them to help the body defend itself against leukemia and other forms of cancer.

Living with Leukemia

Living with leukemia can be difficult. Not only can the disease make someone feel sick, but the treatments can, too. Fortunately, though, these treatments often make the disease go into remission. Once this happens, patients still need to see their doctors often for follow-up visits and tests. That way, if the leukemia comes back, it will be detected as quickly as possible.

Having leukemia can be difficult emotionally, too. It is scary for patients to find out that they have a form of cancer and to worry about what the future may hold. Some people withdraw, get angry, or get depressed when they are diagnosed with leukemia. However, with the support of family, friends, support groups, and health professionals, a spirit of realistic optimism can win out.

See also

Anemia

Cancer

Radiation Exposure Conditions

Resources

Books

Keene, Nancy. Childhood Leukemia: A Guide for Family, Friends, and Caregivers. Sebastopol, CA: O’Reilly and Associates, 1997. This book is written mainly for parents, but it offers a wealth of practical advice on coping with childhood leukemia.

Organizations

American Cancer Society, 1599 Clifton Road Northeast, Atlanta, GA 30329-4251. This large nonprofit organization provides information about leukemia in both children and adults. Telephone 800-ACS-2345 http://www.cancer.org

Leukemia Society of America, 600 Third Avenue, New York, NY 10016. This nonprofit organization provides extensive information about leukemia to the public. Telephone 800-955-4572 http://www.leukemia.org

National Bone Marrow Transplant Link, 29209 Northwestern Highway, Number 624, Southfield, MI 48034. A support organization for bone marrow transplant patients. Telephone 800-LINK-BMT http://comnet.org/nbmtlink

U.S. National Cancer Institute, Building 31, Room 10A03, 31 Center Drive, Bethesda, MD 20892-2580. This U.S. government agency provides detailed information about leukemia and posts a fact sheet What You Need to Know About Leukemia at its website. Telephone 800-4-CANCER http://rex.nci.nih.gov http://cancernet.nci.gov/wyntk_pubs/index.html