Leukaemia

Leukaemia is a cancer of the blood that starts when abnormal cells multiply rapidly in the bone marrow, crowding out healthy blood cells and affecting the body’s ability to fight infections, carry oxygen, and form blood clots.

Table of contents

• What is leukaemia?
• How leukaemia develops in the body
• Main types of leukaemia
• Signs and symptoms
• Risk factors
• How leukaemia is diagnosed
• Treatment options
• Living with leukaemia

What is leukaemia?

Leukaemia is a cancer of the blood, characterised by the rapid growth of abnormal blood cells^[1]. This type of cancer starts in bone marrow, the soft, spongy tissue inside some of your bones where your body makes blood cells^[1]. The term leukaemia comes from the Greek words for “white” (leukos) and “blood” (haima)^[1].

In leukaemia, blood cells are not produced the way they should be and you may have too many, too few, or blood cells that don’t work properly^[9]. Unlike other cancers, leukaemia doesn’t generally form a mass or tumour that shows up in imaging tests such as X-rays or CT scans^[1].

Leukaemia is one of the most common types of cancer. It occurs most often in adults older than 55 years, but it is also the most common cancer in children younger than 15 years^[2]. Globally, an estimated 474,519 new cases of leukaemia are diagnosed each year, with about 60,000 new cases in the United States in 2023^[6][13].

How leukaemia develops in the body

Leukaemia begins in bone marrow, where your body’s blood cells are made. Blood cells go through multiple stages before reaching their fully mature forms. Normally, mature blood cells include red blood cells (cells that carry oxygen), white blood cells (cells that fight infection), and platelets (cells that help your blood clot)^[1].

These blood cells start as stem cells that develop into either myeloid cells or lymphoid cells. Myeloid cells develop into red blood cells, platelets and certain types of white blood cells. Lymphoid cells develop into certain white blood cells called lymphocytes and natural killer cells^[1].

However, when you have leukaemia, one of the developing blood cells begins to multiply out of control^[1]. The disease starts when the DNA of a single cell in your bone marrow changes (mutates) and can’t develop and function normally^[11]. These abnormal cells, called leukaemia cells, are usually immature white blood cells that begin to take over the space inside of your bone marrow^[1][3].

Having too many leukaemia cells and too few normal cells is harmful for several reasons. Leukaemia cells serve no purpose in keeping you healthy. Normal blood cells have very little space and support to mature and multiply inside of your bone marrow because the leukaemia cells overtake them. As a result, fewer red blood cells, healthy white blood cells and platelets are made and released into your blood^[1]. This means your body’s organs and tissues won’t get the oxygen needed to work properly, your body won’t be able to fight infections, or form blood clots when needed^[1].

Main types of leukaemia

There are many types of leukaemia. Healthcare providers classify leukaemia based on how fast the disease worsens and whether leukaemia cells arise from myeloid cells or lymphoid cells^[1].

By speed of disease progression, leukaemia can be classified as:

• Acute leukaemia: The leukaemia cells divide rapidly and the disease progresses quickly. If you have acute leukaemia, you’ll feel sick within weeks of the leukaemia cells forming. Acute leukaemia is life-threatening and requires immediate treatment^[1].
• Chronic leukaemia: This type develops slowly over months or years. Chronic leukaemia progresses more slowly than acute leukaemia^[3].

Based on the type of blood cell involved, leukaemia can be:

• Lymphocytic (or lymphoblastic) leukaemia: This develops from abnormal lymphoid stem cells. Lymphocytic leukaemia refers to abnormal cell growth in the marrow cells that become lymphocytes, a type of white blood cell that plays a role in the immune system^[3][8].
• Myeloid (or myelogenous) leukaemia: This develops from abnormal myeloid stem cells. In myelogenous leukaemia, abnormal cell growth occurs in the marrow cells that mature into red blood cells, white blood cells, and platelets^[3][8].

The four main types of leukaemia are:

• Acute lymphoblastic leukaemia (ALL): A fast-growing cancer that starts in lymphoid cells. ALL is the most common form of childhood leukaemia^[3]. Among children and teens, ALL accounts for 75% of paediatric leukaemia cases^[13].
• Acute myeloid leukaemia (AML): A fast-growing cancer that starts in myeloid cells. AML is the second most common type in children and accounts for 32% of adult cases^[3][8].
• Chronic lymphocytic leukaemia (CLL): A slower-growing cancer that starts in lymphoid cells. CLL is one of the most common types of leukaemia in adults, often occurring during or after middle age. It accounts for 35% of adult cases^[3][7][8].
• Chronic myeloid leukaemia (CML): A slower-growing cancer that starts in myeloid cells, usually occurring in adults during or after middle age^[7].

Other less common types include hairy cell leukaemia, large granular lymphocytic leukaemia, acute promyelocytic leukaemia, and chronic myelomonocytic leukaemia^[9][16].

Signs and symptoms

Leukaemia symptoms vary depending on the type of leukaemia. Symptoms are often nonspecific and can include fever, fatigue, weight loss, bone pain, bruising or bleeding^[6]. Common leukaemia signs and symptoms include^[2]:

• Fever or chills
• Persistent fatigue, weakness
• Frequent or severe infections
• Losing weight without trying
• Swollen lymph nodes, enlarged liver or spleen
• Easy bleeding or bruising
• Recurrent nosebleeds
• Tiny red spots in your skin (petechiae)
• Excessive sweating, especially at night
• Bone pain or tenderness

Symptoms can also include headaches, swollen or bleeding gums, swollen tonsils, skin rashes, hair loss, and paleness^[3]. Sometimes leukaemia is discovered during blood tests for some other condition, as early leukaemia symptoms may resemble symptoms of the flu and other common illnesses^[2]. Chronic leukaemia may not cause symptoms at first^[7].

Risk factors

Although experts are uncertain about the exact causes of leukaemia, they have identified several risk factors^[3]:

• Exposure to high levels of radiation
• Repeated exposure to certain chemicals, for example benzene
• Previous chemotherapy treatment
• Down syndrome and other genetic conditions
• A strong family history of leukaemia

Many genetic risk factors have been identified, such as Klinefelter and Down syndromes, ataxia telangiectasia, Bloom syndrome, and telomeropathies such as Fanconi anaemia, dyskeratosis congenita and Shwachman-Diamond syndrome. Germline mutations in certain genes have also been implicated^[6].

Viral infections associated with Epstein Barr virus and human T-lymphotropic virus, ionising radiation exposure, radiation therapy, environmental exposure to benzene, smoking history, and history of chemotherapy with alkylating agents and topoisomerase II agents have also been implicated in the development of acute leukaemias^[6].

Your risk of leukaemia goes up as you age. It is most common over age 60^[7].

How leukaemia is diagnosed

Your healthcare provider may use many tools to diagnose leukaemia^[7]:

• A physical exam
• A medical history
• Blood tests, such as a complete blood count (CBC)
• Bone marrow tests
• Genetic tests to look for gene and chromosome changes

Your doctor will conduct a complete blood count to determine if you have leukaemia. This test may reveal if you have leukaemic cells. Abnormal levels of white blood cells and abnormally low red blood cell or platelet counts can also indicate leukaemia^[3].

By looking at a sample of your blood, your doctor can determine if you have abnormal levels of red or white blood cells or platelets, which may suggest leukaemia. A blood test may also show the presence of leukaemia cells, though not all types of leukaemia cause the leukaemia cells to circulate in the blood. Sometimes the leukaemia cells stay in the bone marrow^[10].

If you test positive for leukaemia, your doctor will perform a biopsy of your bone marrow to determine which type you have^[3]. There are two main types of bone marrow tests: bone marrow aspiration and bone marrow biopsy. Both tests involve removing a sample of bone marrow and bone, usually taken from a spot in the back of the hip bone. The samples are sent to a laboratory for testing^[7][10].

Specialised tests of your leukaemia cells may reveal certain characteristics that are used to determine your treatment options^[10]. Once the provider makes a diagnosis, there may be additional tests to see whether the cancer has spread. These include imaging tests and a lumbar puncture, which is a procedure to collect and test cerebrospinal fluid^[7].

Treatment options

Treatment for leukaemia depends on the type of leukaemia you have, your age and overall health, and whether the leukaemia has spread to other organs or tissues^[1]. Treatment can be complex, but there are strategies and resources that can help make your treatment successful^[2].

The following treatments may be offered for leukaemia^[15]:

• Chemotherapy: This is the main treatment for many types of leukaemia. It involves using drugs at high doses to kill cancerous cells in your blood and bone marrow^[3][14]. You’ll usually be given a combination of two or more chemotherapy medicines^[14]. Patients with acute leukaemia often undergo chemotherapy because this type of treatment targets fast-dividing cells^[3].
• Radiation therapy: This is most often used to target areas of the body where leukaemia cells have built up. It is also used to prepare the bone marrow for a stem cell transplant^[15]. Radiotherapy involves using high doses of controlled radiation to kill cancerous cells^[14].
• Targeted therapy: This is offered for some types of leukaemia. It uses drugs or other substances that attack specific cancer cells with less harm to normal cells^[7][15]. Because the cells divide more slowly in chronic leukaemia, it is better treated with targeted therapies that attack slowly dividing cells as opposed to traditional chemotherapy that targets rapidly dividing cells^[3].
• Stem cell transplant: This is used for some people with certain types of leukaemia^[15]. It may be recommended if the cancer has come back or is not responding to other treatments^[14].
• Immunotherapy: This class of treatments takes advantage of a person’s own immune system to help kill cancer cells. There are currently ten FDA-approved immunotherapy options for leukaemia, including targeted antibodies and adoptive cell therapy^[13].
• Surgery: This may be used in rare cases to remove the spleen^[15].
• Watchful waiting: This is a treatment option for some people with chronic leukaemia^[15].

Side effects of intensive chemotherapy for leukaemia are common. They can include feeling or being sick, bruising or bleeding easily, diarrhoea, loss of appetite, sore mouth and mouth ulcers, tiredness, skin rashes, hair loss, and infertility, which may be temporary or permanent^[14]. Most side effects should resolve once treatment has finished. Tell a member of your care team if side effects become particularly troublesome, as there are medicines that can help you cope better with certain side effects^[14].

For some patients, participating in a clinical trial provides access to experimental therapies. If you are diagnosed with leukaemia, talk with your doctor about whether joining a clinical trial is right for you^[3].

Living with leukaemia

Receiving a leukaemia diagnosis can feel life changing. Learning that you have cancer is a life-changing experience. After your leukaemia diagnosis, you may feel afraid, anxious, overwhelmed and uncertain about how you will get through the days ahead^[20].

It’s important to remember that your mental health is a crucial part of your overall health and well-being. Having cancer may require you to make some changes to your routine, but it doesn’t have to change everything about your life^[19].

Chronic cancers like CLL will always be part of your life. It is different to some other types of cancer that go away when treatment ends. Although some people can eventually stop treatment, for many people there isn’t an end to the treatment or tests. So you can’t plan for a life after cancer. It can be difficult to adjust to this^[18]. Most people will need to learn to live with taking daily medicines and the side effects. You will need regular blood tests and hospital visits^[18].

Self-care and lifestyle

It’s critical to take time to care for yourself physically and mentally during and after cancer treatment^[17]:

• Nutrition: Fruits, vegetables, lean proteins and whole grains give you more strength than processed foods can. They can also help you manage treatment side effects, maintain a healthy weight and lower your risk of infection. Drink plenty of fluids (about eight 8-ounce glasses a day) to keep your body’s minerals in balance^[17].
• Exercise: Exercise is an essential part of a cancer treatment plan. Research shows that regular exercise can significantly improve physical and mental health during every phase of treatment. If you’re new to exercise, check with your doctor before beginning. Start slow and build up to 30 minutes a day^[17].
• Schedule time for self-care: Research shows that regular self-care practices can reduce the adverse effects of stress, sleep disturbances and anxiety that comes along with a leukaemia diagnosis. Ideas include finding quiet time alone, doing activities you enjoy such as reading or walking, starting a journal, getting a massage and prioritising sleep^[20].

Getting support

Try to talk to your friends and family about what is happening and how you feel. This can also help them support you^[18]. Friends and family can drive you to appointments, help with errands and household chores, and prepare meals for you. Although it may be difficult, try to learn to accept their help^[20].

Get the facts by obtaining as much information about your type of leukaemia as you can to help you make decisions about your care. It is best to get this information from your doctor. Before your first few appointments, write down all your questions and concerns and bring them with you^[20].

Get in touch with your doctor or specialist nurse if you are worried about any symptoms. They might be able to reassure you, or they can find out the cause and help you get treatment if you need it^[18].