Therapy focus: Leukaemia

Leukaemia is a type of cancer which affects the blood cells. In the UK, leukaemia is the 12th most common cancer in adults, affecting more men than women. It is the most common cancer in children.

Cancer The building blocks of the body are cells, which normally repair and reproduce in a controlled process. With cancer, this process goes wrong and cells divide and grow in an uncontrolled way. The body is made up of many different types of cells, such as skin, nerve, muscle and blood cells. With leukaemia, it is white blood cells that are affected.

About leukaemiaWhite blood cells are produced by the bone marrow, the soft spongy centre of bones. They then pass from the bone marrow into the blood stream and lymph system. White blood cells are involved in various functions of the immune system (the body’s defence system), which protects the body from infections. In leukaemia, some blood cells do not grow properly, but remain within the bone marrow and continue to reproduce in an uncontrolled way. These cells fill up the bone marrow and prevent it from making healthy white blood cells. This means the body is less able to fight off infections. The bone marrow is also able to make other types of blood cells, such as red blood cells and platelets. Problems can result from a reduction in number of these cells. For example, a lack of red blood cells leads to anaemia, which can result in breathlessness and fatigue. A lack of platelets can lead to problems with the blood-clotting system, resulting in bruising. Leukaemia is the most common cancer in children, but cancer is generally rare in children, and leukaemia affects nine times as many adults as children.

Types of leukaemiaThere are many types of leukaemia, named depending on the type of white blood cell affected, and how quickly the disease develops. Only the common types are discussed here. The two main types of leukaemia are acute and chronic. Acute leukaemia tends to affect younger people. The symptoms develop rapidly, and it can quite quickly become life-threatening if not treated. The most common form affects white blood cells called lymphocytes. This is called acute lymphocytic leukaemia (ALL). Chronic leukaemia tends to affect older people. The disease gets worse slowly and has a more prolonged progression. With chronic leukaemia, the white blood cells are almost fully grown and normal when they enter the blood stream. They can function, but not as well as they should do. One type of leukaemia called chronic myeloid leukaemia (CML) affects a particular type of white blood cells called myeloid cells. It has two phases, a chronic phase that may last several years, during which symptoms develop slowly, followed by a more aggressive phase (accelerated phase), where symptoms become rapidly worse.

What causes leukaemia?The cause of most cases of leukaemia is not known, although there are some risk factors that increase the chance of developing the disease. These include:

  • a weakened immune system – this may be a result of drugs that suppress the immune system (such as those used for organ transplants), high doses of radiation (such as in radiotherapy for another cancer), or diseases that affect the immune system (such as HIV)
  • age – chronic leukaemias are more common over the age of 40
  • smoking
  • certain genetic conditions, such as Down’s syndrome
  • previous chemotherapy for another cancer
  • other blood disorders, such as aplastic anaemia, a rare condition where the bone marrow fails to produce blood cells correctly
  • contact with a chemical called benzene, one of the chemicals in petrol and a solvent used in the rubber and plastics industry

Symptoms of leukaemia The symptoms of leukaemia vary greatly, depending on the exact type of disease and how advanced it is. Few or no symptoms may occur in the early stages, especially in people with chronic leukaemia. Many symptoms are vague, such as fever, headaches, weight loss and night sweats.

  • tiredness, breathlessness and pale skin (due to anaemia, a reduction in number of red cells in the blood)
  • frequent infections that do not get better (due to reduction in white blood cells, which fight infection)
  • abnormal bleeding from gums and cuts (due to a reduction in platelets which are important for normal blood clotting)
  • increased bruising (due to platelet reduction)
  • heavier periods in women (due to platelet reduction)
  • nosebleeds (due to platelet reduction)
  • abdominal pain, due to an enlarged spleen or liver
  • swollen lymph glands (glands in the neck, groin and under the arms)
  • bone pain, due to the pressure of cell build-up
  • swollen gums, and occasionally, swollen testicles

DiagnosisLeukaemia can be diagnosed from a blood test to measure the number of blood cells and look for any abnormal cells. People with suspected leukaemia are referred to a specialist doctor, usually a haematologist (an expert in the treatment of blood disorders). Other tests are often performed to investigate the type of leukaemia and how far it has progressed. These include blood tests, X-rays, CT scans, removal of bone marrow for microscopic analysis and genetic analysis of the abnormal cells. These tests are all very important because they help guide the treatment. Diagnosis, investigation, treatment and follow-up for people with leukaemia usually takes place at specialist centres, in hospitals.

TreatmentThe effectiveness of treatment for leukaemia depends on the type and stage of the disease. Acute leukaemia often goes into remission (the symptoms go away; the disease is under control but not necessarily cured). However, many people with acute leukaemia have a relapse (the disease returns). Chronic leukaemias develop more slowly than the acute types, but respond less well to chemotherapy and are rarely cured.

Acute leukaemiaAcute leukaemia is treated with chemotherapy to destroy the abnormal cancer cells. Mixtures of drugs are given into a vein in a series of treatment courses. Medicines are available which reduce the side-effects of chemotherapy such as nausea. Hair may fall out during treatment but it re-grows once the chemotherapy has stopped. Some people may be able to use “cold caps” which cool the scalp and help prevent hair loss. If the leukaemia returns (relapses), intensive treatment may be given. This involves a bone marrow or a stem cell transplant. Bone marrow or stem cell transplants allow much higher doses of chemotherapy to be given. Before transplantation, very high doses of chemotherapy and sometimes radiotherapy are given to destroy all the bone marrow, both abnormal and normal. This improves the chance of completely curing the leukaemia. Then normal bone marrow cells, donated from a close relative or carefully removed from the person’s own bone marrow, are infused into the bloodstream with a drip. Stem cell transplant involves transplanting stem cells (the most basic type of cell, from which all types of blood cells develop), rather than bone marrow cells. Stem cells can be harvested (collected) from a leukaemia patient’s own blood or from a donor. New alternatives, which are currently experimental, include harvesting stem cells from umbilical cord blood or placentas of new born babies.

Chronic leukaemiaTreatment for chronic leukaemia depends on its type and stage. Often treatment is not started unless there are symptoms. In the early stage, treatment aims to control symptoms by reducing the number of abnormal cells in the blood. Biological therapy may be an option for certain types of leukaemia, such as chronic myeloid leukaemia (CML). This involves treatment with natural substances (such as a protein called interferon alfa that helps the immune system fight leukaemia). As the condition becomes more advanced, treatment may consist of mild chemotherapy, blood transfusion and antibiotics for infections. Some evidence indicates that in chronic myeloid leukaemia, bone marrow transplantation can prolong life if performed during its chronic phase. Another available treatment is monoclonal antibodies. Antibodies are proteins that are produced by certain cells in response to infection. They usually attach themselves to bacteria or viruses and help to destroy them. A type of specifically manufactured monoclonal antibody that recognises and selectively destroys leukaemia cells can be infused into the body. An example is alemtuzumab (MabCampath), which is used to treat chronic lymphocytic leukaemia (CLL). For consumer-friendly and reliable health information on over 200 conditions, treatments and living healthily, visit BUPA’s website at: www.bupa.co.uk