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Leukemia is cancer of the blood cells. Cancer is a group of more than 100 diseases that have two important things in common. One is that certain cells in the body become abnormal. Another is that the body keeps producing large numbers of these abnormal cells.
Leukemia is characterised by an excessive production of abnormal white blood cells, overcrowding the bone marrow and often spilling out into the peripheral blood. To understand leukemia, it is helpful to know about normal blood cells and what happens to them when leukemia develops.
The infiltration of the bone marrow results in decreased production and function of normal blood cells. Leukemia, dependent on the type, can spread to the lymph nodes, spleen, liver, central nervous system and other organs or tissues, causing the affected area to swell.
Normal Blood Cells
Normally, blood cells are produced in an orderly, controlled way, as the body needs them. This process helps keep us healthy.
When leukemia develops, the body produces large numbers of abnormal blood cells. In most types of leukemia, the abnormal cells are white blood cells. The leukemia cells usually look different from normal blood cells, and they do not function properly
Types of Leukemia
There are several types of leukemia. They are grouped in two ways. One way is by how quickly the disease develops and gets worse. The other way is by the type of blood cell that is affected.
Leukemia is either acute or chronic. In acute leukemia, the abnormal blood cells are blasts that remain very immature and cannot carry out their normal functions. The number of blasts increases rapidly, and the disease gets worse quickly. In chronic leukemia, some blast cells are present, but in general, these cells are more mature and can carry out some of their normal functions. Also, the number of blasts increases less rapidly than in acute leukemia. As a result, chronic leukemia gets worse gradually.
Leukemia can arise in either of the two main types of white blood cells--lymphoid cells or myeloid cells. When leukemia affects lymphoid cells, it is called lymphocytic leukemia. When myeloid cells are affected, the disease is called myeloid or myelogenous leukemia.
These are the most common types of leukemia:
Leukemia cells are abnormal cells that cannot do what normal blood cells do. They cannot help the body fight infections. For this reason, people with leukemia often get infections and have fevers.
Also, people with leukemia often have less than the normal amount of healthy red blood cells and platelets. As a result, there are not enough red blood cells to carry oxygen through the body. With this condition, called anemia, patients may look pale and feel weak and tired. When there are not enough platelets, patients bleed and bruise easily.
Like all blood cells, leukemia cells travel through the body. Depending on the number of abnormal cells and where these cells collect, patients with leukemia may have a number of symptoms.
In acute leukemia, symptoms appear and get worse quickly. People with this disease go to their doctor because they feel sick. In chronic leukemia, symptoms may not appear for a long time; when symptoms do appear, they generally are mild at first and get worse gradually. Doctors often find chronic leukemia during a routine checkup--before there are any symptoms.
Damage to the bone marrow results in a lack of blood platelets, which are important in the blood clotting process. This means people with leukemia may become bruised, bleed excessively, or develop pinprick bleeds (petechiae).
White blood cells, which are involved in fighting pathogens, may be suppressed or dysfunctional, putting the patient at risk of infection.
Finally, the red blood cell deficiency leads to anemia, which may cause shortness of breath and fatigue. Bone or joint pain may occur because of cancer spreading to these areas. Headaches and vomiting are indicative of the cancer having disseminated to the central nervous system.
Enlarged lymph nodes or splenomegaly (an enlarged spleen) may occur in some types. All symptoms may also be attributable to other diseases; for diagnosis, blood tests and a bone marrow biopsy are required.
Some other related symptoms:
In chronic leukemia, the abnormal blood cells may gradually collect in various parts of the body. Chronic leukemia may affect the skin, central nervous system, digestive tract, kidneys, and testicles
To find the cause of a person's symptoms, the doctor asks about the patient's medical history and does a physical exam. In addition to checking general signs of health, the doctor feels for swelling in the liver; the spleen; and the lymph nodes under the arms, in the groin, and in the neck.
Blood tests also help in the diagnosis. A sample of blood is examined under a microscope to see what the cells look like and to determine the number of mature cells and blasts. Although blood tests may reveal that a patient has leukemia, they may not show what type of leukemia it is.
To check further for leukemia cells or to tell what type of leukemia a patient has, a hematologist, oncologist, or pathologist examines a sample of bone marrow under a microscope. The doctor withdraws the sample by inserting a needle into a large bone (usually the hip) and removing a small amount of liquid bone marrow. This procedure is called bone marrow aspiration. A bone marrow biopsy is performed with a larger needle and removes a small piece of bone and bone marrow.
If leukemia cells are found in the bone marrow sample, the patient's doctor orders other tests to find out the extent of the disease. A spinal tap (lumbar puncture) checks for leukemia cells in the fluid that fills the spaces in and around the brain and spinal cord (cerebrospinal fluid). Chest x-rays can reveal signs of disease in the chest
Treatment for leukemia is complex. It varies with the type of leukemia and is not the same for all patients. The doctor plans the treatment to fit each patient's needs. The treatment depends not only on the type of leukemia, but also on certain features of the leukemia cells, the extent of the disease, and whether the leukemia has been treated before. It also depends on the patient's age, symptoms, and general health.
Whenever possible, patients should be treated at a medical center that has doctors who have experience in treating leukemia. If this is not possible, the patient's doctor should discuss the treatment plan with a specialist at such a center. Also, patients and their doctors can call the Cancer Information Service to request up-to-date treatment information from the National Cancer Institute's PDQ database.
Acute leukemia needs to be treated right away. The goal of treatment is to bring about a remission. Then, when there is no evidence of the disease, more therapy may be given to prevent a relapse. Many people with acute leukemia can be cured.
Chronic leukemia patients who do not have symptoms may not require immediate treatment. However, they should have frequent checkups so the doctor can see whether the disease is progressing. When treatment is needed, it can often control the disease and its symptoms. However, chronic leukemia can seldom be cured.
Many patients and their families want to learn all they can about leukemia and the treatment choices so they can take an active part in decisions about medical care. The doctor is the best person to answer these questions. When discussing treatment, the patient (or, in the case of a child, the patient's family) may want to talk with the doctor about research studies of new treatment methods. Such studies, called clinical trials, are designed to improve cancer treatment.
When a person is diagnosed with leukemia, shock and stress are natural reactions. These feelings may make it difficult to think of every question to ask the doctor. Also, patients may find it hard to remember everything the doctor says.
Often, it helps to make a list of questions to ask the doctor. Taking notes or, if the doctor agrees, using a tape recorder can make it easier to remember the answers. Some people find that it also helps to have a family member or friend with them--to take part in the discussion, to take notes, or just to listen. Patients do not need to ask all their questions or remember all the answers at one time. They will have other chances for the doctor to explain things that are not clear and to ask for more information.
Here are some questions patients and their families may want to ask the doctor before treatment begins:
Methods of Treatment
Most patients with leukemia are treated with chemotherapy. Some also may have radiation therapy and/or bone marrow transplantation (BMT) or biological therapy. In some cases, surgery to remove the spleen (an operation called a splenectomy) may be part of the treatment plan.
Some anticancer drugs can be taken by mouth. Most are given by IV injection (injected into a vein). Often, patients who need to have many IV treatments receive the drugs through a catheter.
One end of this thin, flexible tube is placed in a large vein, often in the upper chest. Drugs are injected into the catheter, rather than directly into a vein, to avoid the discomfort of repeated injections and injury to the skin.
Anticancer drugs given by IV injection or taken by mouth enter the bloodstream and affect leukemia cells in most parts of the body. However, the drugs often do not reach cells in the central nervous system because they are stopped by the blood-brain barrier. This protective barrier is formed by a network of blood vessels that filter blood going to the brain and spinal cord. To reach leukemia cells in the central nervous system, doctors use intrathecal chemotherapy. In this type of treatment, anticancer drugs are injected directly into the cerebrospinal fluid.
Intrathecal chemotherapy can be given in two ways. Some patients receive the drugs by injection into the lower part of the spinal column. Others, especially children, receive intrathecal chemotherapy through a special type of catheter called an Ommaya reservoir. This device is placed under the scalp, where it provides a pathway to the cerebrospinal fluid. Injecting anticancer drugs into the reservoir instead of into the spinal column can make intrathecal chemotherapy easier and more comfortable for the patient.
Chemotherapy is given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. In some cases, the patient has chemotherapy as an outpatient at the hospital, at the doctor's office, or at home. However, depending on which drugs are given and the patient's general health, a hospital stay may be necessary.
Radiation therapy for leukemia may be given in two ways. For some patients, the doctor may direct the radiation to one specific area of the body where there is a collection of leukemia cells, such as the spleen or testicles. Other patients may receive radiation that is directed to the whole body. This type of radiation therapy, called total-body irradiation, usually is given before a bone marrow transplant.
Side Effects of Treatment
Chemotherapy - side effects
The side effects of chemotherapy depend mainly on the drugs the patient receives. In addition, as with other types of treatment, side effects may vary from person to person. Generally, anticancer drugs affect dividing cells. Cancer cells divide more often than healthy cells and are more likely to be affected by chemotherapy. Still, some healthy cells also may be damaged. Healthy cells that divide often, including blood cells, cells in hair roots, and cells in the digestive tract, are likely to be damaged. When chemotherapy affects healthy cells, it may lower patients' resistance to infection, and patients may have less energy and may bruise or bleed easily. They may lose their hair. The also may have nausea, vomiting, and mouth sores. Most side effects go away gradually during the recovery periods between treatments or after treatment stops.
Some anticancer drugs can affect a patient's fertility. Women's menstrual periods may become irregular or stop, and women may have symptoms of menopause, such as hot flashes and vaginal dryness. Men may stop producing sperm. Because these changes may be permanent, some men choose to have their sperm frozen and stored. Most children treated for leukemia appear to have normal fertility when they grow up. However, depending on the drugs and doses used and on the age of the patient, some boys and girls may not be able to have children when they mature.
Radiation Therapy - side effects
Patients receiving radiation therapy may become very tired. Resting is important, but doctors usually suggest that patients remain as active as they can.
When radiation is directed to the head, patients often lose their hair. Radiation can cause the scalp or the skin in the treated area to become red, dry, tender, and itchy. Patients will be shown how to keep the skin clean. They should not use any lotion or cream on the treated area without the doctor's advice. Radiation therapy also may cause nausea, vomiting, and loss of appetite. These side effects are temporary, and doctors and nurses can often suggest ways to control them until the treatment is over.
However, some side effects may be lasting. Children (especially young ones) who receive radiation to the brain may develop problems with learning and coordination. For this reason, doctors use the lowest possible doses of radiation, and they give this treatment only to children who cannot be treated successfully with chemotherapy alone.
Also, radiation to the testicles is likely to affect both fertility and hormone production. Most boys who have this form of treatment are not able to have children later on. Some may need to take hormones.
Bone Marrow Transplantation - side effects
Patients who have a bone marrow transplant face an increased risk of infection, bleeding, and other side effects of the large doses of chemotherapy and radiation they receive. In addition, graft-versus-host disease (GVHD) may occur in patients who receive bone marrow from a donor. In GVHD, the donated marrow reacts against the patient's tissues (most often the liver, the skin, and the digestive tract). GVHD can be mild or very severe. It can occur any time after the transplant (even years later). Drugs may be given to reduce the risk of GVHD and to treat the problem if it occurs.
Nutrition for Cancer Patients
Some cancer patients find it hard to eat well. They may lose their appetite. In addition, the common side effects of therapy, such as nausea, vomiting, or mouth sores, can make eating difficult. For some patients, foods taste different. Also, people may not feel like eating when they are uncomfortable or tired.
Eating well means getting enough calories and protein to help prevent weight loss and regain strength. Patients who eat well during cancer treatment often feel better and have more energy. In addition, they may be better able to handle the side effects of treatment.
Doctors, nurses, and dietitians can offer advice for healthy eating during cancer treatment. Patients and their families also may want to read the National Cancer Institute booklets Eating Hints for Cancer Patients and Managing Your Child's Eating Problems During Cancer Treatment, which contain many useful suggestions
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