What is Leukaemia?

Leukaemia is the medical term for cancer of the blood. There is normally a healthy balance between the production of new blood cells in the bone marrow and the number of cells circulating in the blood vessels. Leukaemia develops when one of the bone marrow cells starts to grow in an uncontrolled fashion. When this occurs, the leukaemia cells outgrow their normal counterparts. There are several types of leukaemia, depending on which type of bone marrow cell is affected. The remaining healthy cells in the bone marrow have less space in which to develop, which means that fewer red blood cells and platelets are produced.

Leukaemias represent around 1% of all cancers diagnosed in Ireland. Overall, leukaemia is slightly more common in men than in women. About 90% of all leukaemias are diagnosed in adults.  It is estimated, based on UK figures, that the lifetime risk of developing leukaemia is 1 in 76 for men and 1 in 108 for women.

Leukaemias are treated by haematologists, doctors specialising in diseases of the blood.

Blood and Bone Marrow

All of the different types of blood cells are made in the bone marrow.  Marrow is a spongy material that fills the middle of some of the larger bones. Ultimately, all the blood cells develop from  a small number of “stem” cells.  These stem cells mature into the three main types of cells in the blood: red cells, white cells and platelets.  When they are fully grown, these various cells are released from the bone marrow into the blood and circulate around the body to where they are needed.

• Red blood cells carry oxygen to all our tissues
• White blood cells are essential for fighting infection
• Platelets help to prevent bleeding

The stem cells come in two forms, myeloid stem cells that give rise to most of the blood components including red cells, most of the white cells and platelets, and lymphoid stem cells which mature into lymphocytes. These are specialised cells of the immune system which play a vital role in protecting us against infection. As lymphocytes can be divided into B-cells and T-cells, there are corresponding B-cell and T-cell forms of Acute Lymphoblastic Leukaemia.

Main Types Of Leukaemia?

From a clinical perspective, there are two main types of leukaemia, acute and chronic.

Acute - Acute leukemia is characterised by a rapid increase in the number of immature blood cells. Crowding due to such cells leaves the bone marrow unable to produce healthy blood cells. Immediate treatment is required due to the rapid growth of the malignant cells, which then spill over into the blood. Acute forms of leukemia are the most common forms of leukemia in children. Urgent admission to hospital is required for the diagnosis and treatment of an acute leukaemia. 

Acute Leukaemia comprises two forms: Acute Myeloid Leukaemia (AML) and Acute Lymphoblastic Leukaemia.  (ALL). Both diseases present in a similar fashion with overproduction of bone marrow precursors and reduced production of the normal cells in the blood.  While the initial supportive care of both diseases is identical, an exact diagnosis is required as specific treatments are required for the various forms of leukaemia. 

 Chronic - The excessive build up of relatively mature, but still abnormal, white blood cells characterises chronic leukemias. Typically taking months or years to progress, the cells are produced at a slightly higher rate than normal cells, resulting in many abnormal white blood cells in the blood. Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before there is any need for treatment. Chronic leukemia mostly occurs in older people, but can occur in any age group.

As with Acute Leukaemia, there are two broad categories of chronic leukaemias, myeloid and lymphoproliferative. Chronic Myeloid Leukaemia (CML) is characterised by the overproduction of mature white cells. This type of leukaemia can occur at any age, but is more likely in middle-aged and older people. The other group is made of many types of chronic lymphoproliferative disorders, of which the most common is Chronic Lymphocytic Leukaemia (CLL).

Normally, lymphocytes die off naturally at the end of their life span. In CLL, however, these cells build up in the bone marrow until there is no space for normal blood cells to develop.  CLL is the most common leukaemia in the Western World and the chance of developing it increases with age.  Most diagnoses are made in people over 60 years of age.  It rarely occurs on people under the age of 30 years and does not affect children.  It is more common in men than women..

What Causes Leukaemia?

The exact causes of leukaemia are unknown

The risk factors for Acute Myeloid Leukaemia (AML) include increasing age, smoking, exposure to high doses of radiation, benzene and previous treatment for cancer.  It is also linked with Down’s syndrome, and some blood disorders like Fanconi anaemia, myelodysplastic syndromes (MDS) and myeloproliferative disorders, especially in those aged over 65 years of age.

People who have been exposed to large doses of radiation (such as after the atom bomb in Japan) or after radiotherapy for cancer treatment have sometimes developed Chronic Myeloid Leukaemia (CML) many years later. People who have been exposed to benzene for a long time also have a higher risk of developing CML.

The cause of CLL is unknown.  There is no evidence that exposure to chemicals, radiation, smoking, diet, or viral infections causes it.

it is important to be aware that most leukaemia is thought to occur spontaneously as we age and is not a reflection of lifestyle factors.

What are the Symptoms of Leukaemia?

In general, the symptoms in these diseases reflect the inability of the bone marrow to produce normal blood cells. Acute leukaemias essentially present with bone marrow failure whereas more chronic forms may present with swollen lymph glands or be picked up on routine blood tests.  

Red cells contain an oxygen-carrying molecule called haemoglobin. When the level of haemoglobin falls, this results in anaemia. The symptoms of anaemia are fatigue and breathlessness, especially on exertion. An anaemic individual may appear pale.  

When the production of normal white cells is affected, the ability to defend ourselves against infection may be reduced. Patients may present with swollen lymph glands, sores that fail to heal and persistent chest infections. 

Platelets prevent bleeding when a blood vessel is cut. When the levels of platelets falls markedly, we become prone to spontaneous bruising or bleeding. Occasionally, patients may present with many small red spots, especially on the shins and ankles. These are called petechiae and reflect bleeding from small blood vessels into the skin.  

More generally, patients may feel non-specifically unwell or have a fever.  

The symptoms vary, depending on the exact type of leukaemia you have and how advanced it is. You may have no symptoms in the early stages, especially if you have chronic leukaemia. Your symptoms may be mild at first and then get worse and you may feel as if you have flu.

If you experience more than one of these symptoms, especially if they come on suddenly, you should consult your GP who can arrange for blood tests.

Diagnosing Leukaemia

Your GP will ask you about your symptoms and examine you. If your GP thinks you may have leukaemia, he or she will refer you to a haematologist.

It should be stressed that  almost all the symptoms associated with leukemia are more commonly due to other diseases. Consequently, leukemia is only ever diagnosed following medical tests.

You will need to have a blood test. The standard test is a Full Blood Count (FBC) where a sample of blood is sent, by your doctor, to the laboratory to count the number and types of blood cells. If required, a smear of blood will be looked at under a microscope to detect any abnormal cells. Depending on the results of the blood test, you may need to have further tests, which may include the following -

A bone marrow aspirate and biopsy to examine the bone marrow cells under a microscope. This is not always necessary.  However, if it is required, the sample is usually taken from your hip bone and you will be given a local anaesthetic to numb the area beforehand. This procedure is often performed as an outpatient.

 Bone Marrow Cytogenetic Analysis - this specialised test provides crucial information about the genetic changes within the leukaemic cells. This information is helpful is determining the choice of treatment.   

Immunophenotyping (or flow cytometry) - this test provides more information on the exact subtype of leukaemia  

CT, MRI, X-ray or ultrasound scans to look for enlarged lymph nodes, an enlarged spleen or other tumours

An echocardiogram to check that your heart is healthy

Tissue typing of yourself and your siblings to see if you have a suitable bone marrow donor

How can Leukaemia be Treated?

Treatment varies considerably, depending on the type of leukaemia you have, but may involve:

Chemotherapy - medicines that destroy cancer cells.  This usually starts in the hospital and is intravenous. This usually requires admission to hospital. Each course of chemotherapy can last a number of days. The initial treatment of acute leukaemia will usually require a five-week admission. This consists of the initial administration of intensive chemotherapy, a number of weeks of transfusion support therafter and finally the slow recovery of blood cells. Usually, patients will be referred to a specialist unit, such as the one at St. James’ Hospital, Dublin, for care.

Radiotherapy - Radiation therapy (radiotherapy), also called "irradiation," may be used to treat blood cancers in the context of transplantation (leukaemia, lymphoma, myeloma or myelodysplastic syndromes). The type of radiation (called "ionizing radiation") that is used for radiotherapy is the same type that is used for diagnostic x-rays, but radiotherapy is given in higher doses.

 Radiotherapy works by damaging the genetic material (DNA) within cells, which prevents the cells from growing and reproducing.  Although the radiotherapy is directed at cancer cells, healthy cells near the cancer cells may also be damaged. However, a goal of radiotherapy is to protect the healthy cells as much as possible, so that the benefit (destroying the cancer cells) outweighs the risk (harming healthy cells). If you need a stem cell transplant, you may need a special form of radiotherapy called total body irradiation (TBI).

A bone marrow or stem cell transplant - transferring healthy bone marrow or stem cells into your body to give you a source of healthy bone marrow.  This can be done by using bone marrow or stem cells donated by someone else (allogeneic transplant) or by using your own bone marrow or stem cells (autologous transplant). If you do not have a family member who is a good match, the hospital will search for an unrelated donor for you.  There is a register of donors in Ireland. If a match is not found in the registry, than a wider search through international registries will take place. The Irish Unrelated Bone Marrow Registry (IUBMR) is part of The Irish Blood Transfusion Service (IBTS).

The IUBMR performs unrelated searches on your behalf, both in Ireland and in Unrelated Bone Marrow Registries worldwide. On the 3rd October 2008, the Irish Unrelated Bone Marrow Registry facilitated the 200th Stem Cell transplant for Irish patients.

You may need to have other treatment, possibly including antibiotics, blood transfusions, platelet transfusions and growth factor injections.

How well treatment for leukaemia works depends on the type and stage of the disease. Acute leukaemia often goes into remission. This is when your symptoms go away and the disease is under control, but not necessarily cured. Unfortunately, for many people with acute leukaemia, remission is followed by a relapse - when the disease returns.

Other sites for Leukaemia Information and Support

If you are diagnosed with leukaemia, you can be sure that you will receive plenty of information and support from your local hospital or from St James Hospital

You can contact us at the Bone Marrow for Leukaemia Trust at This e-mail address is being protected from spambots. You need JavaScript enabled to view it or ring us on 01 473 8314

The Irish Cancer Society offers information and support to all people with cancer, including leukaemia. They have a website at www.cancer.ie and run a telephone cancer helpline at 1800 200700.