Definition Leukaemia is a cancer that affects white blood cells. There are many types of leukaemia. Each one is named for the kind of white blood cell it affects. These include myelocytes, lymphocytes, plasma cells, and other types of white blood cells.
Leukaemia is also characterised as being acute or chronic. Acute leukaemia refers to a leukaemia that is very aggressive and worsens over a brief period. Examples of acute leukaemia are:
Certain types of chronic leukaemia eventually develop into a form of acute leukaemia.
What is going on in the body? All blood components are produced in the bone marrow. These components include white blood cells (which fight infections), red blood cells (which carry oxygen), and platelets (used in blood clotting). The bone marrow is very active because blood cells must be replaced all the time.
When a white blood cell undergoes cancerous changes, it begins growing and multiplying uncontrollably. The cancerous white cells crowd out the other blood cells. Eventually, the cancerous cells take up so much of the bone marrow that normal amounts of blood cells are not produced. Eventually, some of the cancerous white cells leave the bone marrow and go into the bloodstream. Leukaemia does not form solid tumours, like breast cancer or other solid tumour cancers.
What are the signs and symptoms of the disease? As the cancer grows, the bone marrow will become less able to make blood components. Symptoms develop as the bone marrow fails to make these components. The symptoms will develop more quickly in a person with acute leukaemia. Symptoms of chronic leukaemia may develop more slowly.
The person may have severe fatigue from low numbers of red blood cells, known as anaemia.
The person may also bleed or bruise easily because of low numbers of platelets.
The person is likely to have serious infections because the body has so few normal white cells to fight infection.
What are the causes and risks of the disease? It is not known what causes leukaemia. Bone marrow is very sensitive to damage, and some possible causes include:
exposure to large doses of radiation
exposure to certain chemicals, such as benzene
certain genetic defects
in rare cases, certain types of chemotherapy, which can lead to acute leukaemia
some unusual viruses, which can lead to rare types of leukaemia
What can be done to prevent the disease? Nothing can be done to prevent leukaemia.
How is the disease diagnosed? Leukaemia is diagnosed by doing a full blood count, or FBC, to see if it contains cancerous white cells. Special studies are done on these cells to determine the specific type of leukaemia. A bone marrow biopsy, in which a small piece of the bone marrow is removed for examination, can confirm that a person has leukaemia.
What are the long-term effects of the disease? Acute leukaemia of any type can quickly lead to death if it is not treated. Chronic leukaemia will eventually cause death if it is not treated. However, the course of chronic leukaemia may be many months or years. If the treatment is effective, the person may recover and live a normal life.
What are the risks to others? There are no risks to others. No one can acquire leukaemia from contact with a person who has the disease.
What are the treatments for the disease? The treatment of acute leukaemia involves intensive chemotherapy. A combination of powerful medications is given to the person through the veins. These medications are usually given over several months. These medications kill the leukaemia cells but also severely damage the normal cells produced in the bone marrow.
Some people are given bone marrow from another person to help recovery. This is called a bone marrow transplant. It is used only in certain cases.
The first course of therapy is called induction therapy. It is designed to induce a remission, or complete destruction of the leukaemia. The next treatments are called maintenance therapy. These are designed to make the remission last by destroying any remaining disease.
Chronic leukaemia is generally treated with less intense treatments.
Chemotherapy is used for most types of chronic leukaemia. Biological response modifiers (BRMs) may be used for some types of chronic leukaemia. BRMs are elements of the body's immune system that are combined with medications to fight cancer.
What are the side effects of the treatments? Cancerous cells crowd out the normal cells in the bone marrow. Chemotherapy damages normal cells as well as the cancerous cells.
The major side effect of therapy is severe damage to the bone marrow. The person will be at risk for infection until the bone marrow recovers. The infections can be life threatening. The person will have to avoid sources of infection, such as raw food and people with infections, while the bone marrow is recovering.
The person will bleed very easily because the platelets are damaged. Replacement platelets will be given as often as needed to prevent excessive bleeding.
Low red cell counts will make the person very tired. Severe anaemia can cause other problems such as difficulty breathing. Red blood cells will be given to correct the anaemia until the bone marrow recovers.
The person will experience other side effects related to the type of medication administered. Biological response modifiers cause flu-like symptoms. Nausea is common. Hair loss, or alopecia, is another side effect of chemotherapy. Medications will be given to control these symptoms.
What happens after treatment for the disease? After therapy has been completed, the person will recover normal bone marrow function over several weeks. Treatment followed by recovery may be repeated several times until all signs of leukaemia are gone.
How is the disease monitored? Frequent blood tests will be taken to monitor treatment and recovery. Additional bone marrow biopsy samples will be taken to confirm that the leukaemia has been successfully treated. After all therapy has been completed, occasional full blood counts, or FBCs, will be done to make sure the person continues to be in remission. A bone marrow sample may also be needed from time to time.
Author: Miriam P. Rogers, EdD, RN, AOCN, CNS Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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