Acute lymphoblastic leukaemia

What is it?

Acute lymphoblastic leukaemia (ALL) is a type of cancer that affects the blood and bone marrow. ALL is characterised by an overproduction of immature white blood cells, called lymphoblasts or leukaemic blasts. These cells crowd the bone marrow, preventing it from making normal blood cells. They can also spill out into the blood stream and circulate around the body. Due to their immaturity they are unable to function properly to prevent or fight infection. Inadequate numbers of red cells and platelets being made by the marrow cause anaemia, and easy bleeding and/or bruising.

How common is it?

Each year in Australia around 304 people are diagnosed with ALL*. Overall, ALL is a rare disease, accounting for 0.3 per cent of all cancers diagnosed.

Who gets it?

ALL can occur at any age but is more common in young children (0-14 years) who represent close to 60 per cent of all cases. ALL is the most common type of childhood leukaemia, and the most common childhood cancer. It is more common in males than in females.

What causes ALL?

The exact causes of ALL remain largely unknown but it is thought to result from mutations in one or more of the genes that normally control blood cell development. Research is going on all the time into possible causes of this damage and certain factors have been identified that may put some people at an increased risk. These include exposure to:

  • very high doses of radiation either accidentally (nuclear accident) or therapeutically (to treat other cancers)
  • industrial chemicals like benzene, pesticides and certain types of chemotherapy used to treat other cancers.

Certain types of infections and the way in which the immune system reacts may play a role in the development of some types of ALL.

People with certain genetic disorders like Down’s syndrome and Fanconi’s anaemia may have a higher than average risk of developing ALL.

What are the symptoms?

The main symptoms of ALL are caused by a lack of normal blood cells. These include:

  • anaemia due to a lack of red cells ; causing persistent tiredness, dizziness, paleness, or shortness of breath.
  • frequent or repeated infections and slow healing, due to a lack of normal white blood cells, especially neutrophils.
  • increased or unexplained bleeding or bruising, due to a very low platelet count.

Other symptoms may include bone pain, swollen lymph nodes, chest pain and abdominal discomfort due to a swollen spleen or liver.

How is it diagnosed?

ALL is diagnosed by a full blood count (FBC) and a bone marrow biopsy/examination.

How is it treated?

Because it progresses quickly, treatment needs to begin soon after ALL is diagnosed. The type of treatment used will depend on a number of factors including the sub-type of ALL, the genetic make-up of the leukaemic cells, your age and general health.

Chemotherapy is the main form of treatment for ALL. A combination of drugs, including steroids, is usually given in several cycles with a rest period of a few weeks in between. Initially, the aim of treatment is to destroy leukaemic cells and induce a remission. This means that there is no evidence of leukaemic cells in the blood and bone marrow and that normal blood cell production and blood counts are restored. Once a remission has been achieved, further treatment is needed to help destroy any leftover disease, and try to prevent leukaemia from coming back (relapsing) in the future.

Chemotherapy is given in many different ways to treat ALL. This includes intravenously (into a vein), intramuscularly (into a muscle) and in tablet form.

Leukaemic cells can collect in the brain and spinal cord (central nervous system). To prevent and treat disease in this area, chemotherapy is injected intrathecally, directly into the fluid that surrounds these structures. Sometimes, this area is also treated using radiotherapy. In males, radiotherapy may be given to the testes to treat relapsed disease in this area. This can cause infertility.

Treatment is generally ‘risk-based’. This means that you will assigned to a particular treatment plan (protocol) depending on a number of factors, most importantly your risk of relapse in the future. Treatment can last from two to three years or longer depending on the treatment protocol being followed and how well you are progressing and responding to treatment.

People with a particular genetic abnormality found in their leukaemic cells, called the Philadelphia (Ph) chromosome, are also given a drug called imatinib mesylate (Glivec®). This works by blocking the leukaemia-causing effects of the abnormal enzyme tyrosine kinase, which forces leukaemic cells to die.

Occasionally, a stem cell transplant may be used to treat relapsed ALL, or where there is a high likelihood that ALL will relapse in the future.

Many children who are treated for ALL can be cured of their disease. The cure rates for adults with ALL is more variable.

What are the side effects of treatment?

All treatments can cause side effects. The type and severity however will vary between individuals, depending on the type of treatment used and how an individual responds to it. It is important to report any symptoms you are having to your doctor or nurse. In most cases they can be treated and are reversible.

In general, more intensive treatments like stem cell transplant, and treatments that involved radiation to the central nervous system, or total body irradiation (TBI) are associated with more severe side-effects. They can also cause more significant long-term effects, especially in children.

Although ALL affects the bone marrow’s ability to produce adequate numbers of blood cells and platelets, chemotherapy affects this ability further. Blood counts generally fall within a week of treatment and may take some time to recover, depending on the type and doses of drugs used. During this time you are likely to need antibiotics and other drugs to treat, or prevent infection. You are also likely to need blood transfusions to treat severe anaemia, and platelet transfusions to reduce the risk of bleeding.

Other possible side effects of chemotherapy include:

  • feeling sick – nausea and/or vomiting
  • feeling tired and weak
  • hair loss and thinning
  • mouth problems such as mucositis or ulcers
  • diarrhoea or constipation
  • skin problems such as dryness, rash or sensitivity to sunlight
  • fertility problems

Side-effects of steroids depend largely on how long they are used for, and the dose given. Short-term use may cause increased appetite, restlessness or difficulty sleeping. Longer-term use may lead to fluid retention, raised blood sugars and increased susceptibility to infections.

Your doctor and nurse will discuss with you the possible side-effects of your treatment and how they can be managed.

* Source: Australian Institute of Health and Welfare and Australian Associated Cancer Registry (2004) Cancer in Australia 2001