What is acute lymphoblastic leukaemia (ALL)?

Acute lymphoblastic leukaemia (also called ALL or ALL leukemia) is a rare cancer of the blood cells. Around 800 people in the UK are diagnosed with ALL each year. It can develop in people of any age, but is more common in children and young people, and in people over the age of 75. It affects slightly more men than women.

We have separate information about other types of leukaemia.

How ALL develops

Blood cells are made in the bone marrow. This is a spongy material found inside our bones. Every blood cell grows from a stem cell in the bone marrow. Normally, the stem cells make an early stage of the blood cell called a blast. These blasts develop into healthy blood cells.

There are two types of blood stem cell:

  • lymphoid stem cells – make white blood cells called B lymphocytes (B cells) and T lymphocytes (T cells)
  • myeloid stem cells – make red blood cells, platelets and all other types of white blood cell.

MACD261 How blood cells divide

In ALL, the lymphoid stem cells make abnormal blasts that do not fully develop. These abnormal blasts are called leukaemia cells.

Lymphocytes usually fight and prevent infections. However, the leukaemia cells cannot fight infection like normal lymphocytes. They also fill up the bone marrow. This means there is not enough space to make the usual numbers of healthy white blood cells, red blood cells and platelets that your body needs.

Types of ALL

When T cells are affected by leukaemia, this is called T-lymphoblastic leukaemia or T cell leukaemia.

When B cells are affected, it is called B-lymphoblastic leukaemia or B cell leukaemia. This is the most common type of ALL.

Some people with B cell leukaemia have a type called Philadelphia positive ALL (Ph+ ALL). This means tests have found a gene change inside leukaemia cells called the Philadelphia chromosome. This change only affects leukaemia cells. It is not inherited and cannot be passed on to your children.

Treatment for most types of ALL is usually the same. If you have Ph+ ALL, your doctor will add a drug called a tyrosine kinase inhibitor to your treatment.

Symptoms of acute lymphoblastic leukaemia (ALL)

Most symptoms of ALL are caused by leukaemia cells filling the bone marrow. This means healthy blood cells do not move into the blood as normal. Some people have no symptoms and the leukaemia is found after a routine blood test. More often, symptoms appear over a few weeks and people often feel ill quite quickly.

We have more information about possible symptoms of leukaemia.

Causes of acute lymphoblastic leukaemia (ALL)

The cause of ALL is not known. There are some things called risk factors that may increase your risk of developing ALL. We have more information about the risk factors and causes of ALL.

Diagnosis of acute lymphoblastic leukaemia (ALL)

Some people are diagnosed with ALL after being taken to hospital with symptoms that have developed quickly. Others go to see their GP about symptoms. If it is possible you have leukaemia, you will see a doctor who specialises in diagnosing and treating blood problems. This doctor is called a haematologist.

ALL is diagnosed by checking samples of your blood or bone marrow for signs of abnormal cells. The samples are then tested in different ways to find out more about any abnormal cells. We have more information about how tests are used to diagnose leukaemia, and other tests you may have.

If you think you may be pregnant, let your doctor know. Some tests can be harmful to an unborn baby. It is important to talk to your doctor so they can plan your care safely. We have more information about cancer and pregnancy.

Treatment for acute lymphoblastic leukaemia (ALL)

Chemotherapy and drugs called steroids are the main treatments for ALL. The aim is to get rid of the leukaemia cells as quickly as possible, so your bone marrow can work normally again. This is called remission.

Treatment usually starts as soon as possible after diagnosis. Most people in the UK have treatment for ALL as part of research called clinical trials. Before you have any treatment, your doctor will explain the different treatments and their side effects. They will also talk to you about things to think about when making treatment decisions.

Treatments for ALL include:

  • Steroids
    Steroid drugs are almost always used to treat ALL.
  • Chemotherapy
    Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy the leukaemia cells. This is the main treatment for ALL.
  • Intrathecal chemotherapy
    At times during treatment you will have chemotherapy given into the fluid around your spine and brain. This is called intrathecal chemotherapy.
  • Tyrosine kinase inhibitors
    If you have a type of ALL called Philadelphia positive ALL (Ph+ ALL), your treatment will include a drug called a tyrosine kinase inhibitor (TKI). I
  • Stem cell transplant
    An intensive treatment called a donor stem cell transplant is sometimes used as part of ALL treatment.
  • Immunotherapy
    Immunotherapy drugs use the body’s own immune system to recognise and destroy leukaemia cells. This type of treatment is not used very often to treat ALL.

Side effects of treatment

Leukaemia and its treatment can cause symptoms and side effects. Your doctor will monitor these and give you supportive treatment to prevent or manage them.

We have more information about looking after yourself during treatment and recovery.

Tests during treatment

During treatment, your healthcare team will take blood, bone marrow and lumbar puncture samples to check for leukaemia cells. The results of these tests help doctors:

  • see how well your treatment has worked
  • make decisions about your next treatment
  • see if the leukaemia is more likely to come back.

If the tests show very small numbers of leukaemia cells, or none at all, the doctor will say you are in remission. Sometimes very small numbers of leukaemia cells are still found after chemotherapy. This is called minimal residual disease (MRD). It can affect the treatment you need to have.

Treating ALL that comes back

Sometimes ALL comes back after a remission. This is called a relapse. If you relapse, it may be possible to have more treatment and get into a second remission. A long-term remission or cure is the aim of the treatment.

Some people will have a further treatment called a stem cell transplant once they are in remission. This can help reduce the risk of relapse in some situations.

Sometimes treatment can control the leukaemia but not cure it. The aim of treatment is to reduce any symptoms and improve quality of life for as long as possible.

After acute lymphoblastic leukaemia (ALL) treatment

Follow up

After your treatment, you will have regular check-ups. Your doctor or specialist nurse will tell you what to expect. These follow-up appointments will continue for several years. They are a good time to talk about any questions or worries you have.

Your doctor will examine you. They will ask you how you have been feeling and about any new or ongoing side effects.

You will have regular blood tests to check your general health and the number of normal cells in the blood. Depending on the treatment you had, you may also have bone marrow samples taken to check for signs of leukaemia. Sometimes you may need other tests such as x-rays or scans.

Many people find that they get very anxious before these appointments. This is normal. It may help to get support from family and friends.

If you have any problems, or notice any new symptoms between appointments, talk to your doctor or specialist nurse as soon as possible. Do not wait for your next appointment.

Long term effects of treatment

ALL treatment can sometimes cause side effects that are permanent or happen months or years later.

These will not happen to everyone. Your doctor or specialist nurse can explain how likely they are to affect you. They may give you advice about ways to prevent or manage long-term effects.

We have more information about possible long-term or late effects of ALL treatment.

Getting support

Everyone has their own way of dealing with illness and the different emotions they experience. You may find it helpful to talk things over with family and friends or your doctor or nurse.

Macmillan can offer emotional, practical and financial help and support.

The organisations below also offer information and support:

  • ACLT (African Caribbean Leukaemia Trust)
    ACLT offers support for people from ethnic minorities affected by leukaemia and related illnesses.
  • Anthony Nolan
    Anthony Nolan is the UK’s largest stem cell and bone marrow register.
  • Blood Cancer UK
    Blood Cancer UK is a blood cancer research charity that provides information and support on any type of blood cancer.

About our information


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Anne Parker, Consultant Haematologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

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