Leukaemia

Leukaemia is the name given to a group of cancers that originate in the bone marrow and cause abnormal blood cell production.

Cure can be achieved in some cases but treatment options and outcomes depend on a range of factors, including the type of leukaemia, extent of the disease, and age and health of the patient.

Recent statistics indicate around 700 New Zealanders are diagnosed with leukaemia each year.

What is leukaemia?

Bone marrow is soft, “spongy” material in our bones that in healthy people produces a steady supply of new blood cells: red blood cells, which carry oxygen around the body; white blood cells, which help fight infection; and platelets, which have a role in blood clotting.

In people with leukaemia, the bone marrow produces large numbers of abnormal white blood cells that grow and multiply “out of control”. These abnormal cells may not function properly and may affect the ability of normal blood cells to perform their usual functions.

There are many types of leukaemia. Some are more common in children while others are more common in adults. The different types of leukaemia are classified according to how quickly the disease develops and worsens — either chronic (gets worse slowly) or acute (gets worse quickly) — as well as by the type of white blood cell affected — lymphoid cells or myeloid cells.

The four most common types of leukaemia are:

• Chronic lymphocytic leukaemia (CLL): occurs mainly in adults and almost never in children.
• Chronic myeloid leukaemia (CML): occurs mainly in adults.
• Acute lymphoblastic leukaemia (ALL): occurs more commonly in children but also affects adults.
• Acute myeloid leukaemia (AML): occurs in both adults and children.

Risk factors

The precise cause of leukaemia is not known. However, some genetic, environmental and lifestyle factors that increase the likelihood of developing leukaemia have been identified. The risk factors, which differ for different types of leukaemia, include the following:

• Smoking
• Exposure to certain chemicals like benzene
• Previous cancer treatment with certain types of chemotherapy and radiation therapy
• Family history: some people may have a genetic susceptibility to developing leukaemia
• Chromosomal abnormalities: people born with certain genetic conditions, such as Down syndrome.

It should be noted that many people with known risk factors do not get leukaemia and many people with leukaemia have none of these risk factors.

Signs, symptoms, and diagnosis

The symptoms of leukaemia are typically vague and non-specific and may be overlooked early in the disease because they resemble symptoms of the flu and other common illnesses. Additionally, some forms of chronic leukaemia produce no symptoms initially and can go unnoticed and hence untreated for many years.

Depending on the type of leukaemia, symptoms may include:

• Fever or chills
• Fatigue and weakness
• Frequent infections, which may be severe
• Weight loss for no apparent reason
• Swollen lymph nodes and an enlarged liver or spleen
• Bone and joint pain
• Excessive sweating, particularly at night
• Bleeding and bruising easily
• Tiny red spots on the skin.

A diagnosis of leukaemia will involve blood and bone marrow tests. Blood tests are done to determine whether white blood cell counts are abnormally high, which is suggestive of leukaemia. Bone marrow tests are done to help determine appropriate treatment options. It involves removing a sample of bone marrow, usually from the hipbone, and microscopic study of the sample in the laboratory to find leukaemia cells.

Treatment

Treatment of leukaemia depends on the type of leukaemia, the extent of the disease, prior treatment, and the age and health of the patient. The aim of treatment is to destroy the leukaemia cells and make the symptoms go away.

The types of treatment used for leukaemia include:

• Chemotherapy: the main form of treatment for leukaemia. It involves the use of drugs that kill rapidly-growing cells such as leukaemia or other cancer cells. Depending on the type of leukaemia, a single drug or a combination of drugs may be used.
• Biological therapy: this includes the use of man-made drugs that act like antibodies in the immune system.
• Targeted therapy: uses drugs that target specific weaknesses within leukaemia cells to inhibit their growth.
• Radiation therapy (or radiotherapy): uses x-rays or other forms of high-energy radiation to damage or destroy leukaemia cells and stop their growth. Radiation therapy may be used to prepare for a stem cell transplantation.
• Stem cell transplantation: where diseased bone marrow is replaced with blood-forming stem cells that help to rebuild bone marrow. Transplants may be the patient's own stem cells (autologous transplant) or stem cells from another person (allogeneic transplant).

Many people with acute leukaemia can be cured with immediate treatment. Achieving cure in chronic leukaemia is more difficult. Chronic leukaemia without symptoms may not need immediate treatment — a watchful waiting approach may be taken and treatment started once symptoms start to appear.

When treatment for chronic leukaemia is given, its goal is to control the disease and symptoms. Chronic leukaemia is not often cured with chemotherapy but stem cell transplantation may achieve cure in some people. Outcome (prognosis) depends on several factors. These include the patient’s age, type of leukaemia, extent to which the leukaemia has spread, and when in the course of the disease treatment is started.

Further information

The Cancer Society of New Zealand operates a phone service staffed by specialist nurses to support patients diagnosed with cancer, including leukaemia, as well as their friends and families. The Cancer Information Helpline Service can be contacted free of charge on 0800 CANCER (226 237). Information can also be obtained from the Cancer Society website: www.cancernz.org.nz.

Leukaemia & Blood Cancer New Zealand is a nationwide organisation dedicated to supporting patients living with leukaemia and related blood conditions. The organisation provides a toll-free number providing advice, empathy and support on 0800 15 10 15. More information can be obtained by visiting the website: www.leukaemia.org.nz.

References

Ministry of Health (2020). New cancer registrations 2017 (Web Page). Wellington: New Zealand Ministry of Health. https://www.health.govt.nz/publication/new-cancer-registrations-2017 [Accessed 16/11/20]
O’Toole, M.T. (Ed.) (2017). Leukaemia. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed). St Louis, MI: Elsevier.
Stöppler, M.C. (2019). Leukemia (Web Page). MedicineNet.com. New York, NY: WebMD LLC. https://www.medicinenet.com/leukemia/article.htm [Accessed: 16/11/20]

Last reviewed: November 2020

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