Leukemia

Leukemia is a cancer of the blood-forming cells, which are made in the bone marrow. It causes large numbers of white blood cells to be produced. These can crowd the bone marrow and interfere with the production of normal cells, so a person with leukemia is more likely to pick up infections and to have trouble getting rid of them. In many cases, leukemia can be cured or kept under control for many years.

Blood cells and leukemia#

Blood is mostly made up of plasma, a clear fluid. Floating in this fluid are three types of cells:

• red blood cells, which carry oxygen around the body
• white blood cells, which fight disease and infection
• platelets, which help to stop bleeding

These cells are made in the bone marrow, the spongy tissue in the center of the bones. When the body is healthy, the numbers of red cells, white cells and platelets are kept in balance.

In people with leukemia, abnormal cells called blast cells are produced in the bone marrow. These cells cannot carry out their normal function and can crowd the marrow, leaving too little room to make normal white blood cells, red blood cells and platelets. Because so many of the white blood cells are abnormal, a person with leukemia becomes more susceptible to infections.

Causes and risk factors#

The cause of most cases of leukemia is unknown. Several factors may increase the risk of developing it, including:

• exposure to intense levels of radiation (no cases have been linked to radiation from x-rays and CT scans)
• exposure to the chemical benzene, usually in a work environment over long periods
• cigarette smoking, which can increase the risk of some types of leukemia
• genetic factors, as certain inherited conditions can increase the risk
• family history, age and gender (males are at higher risk than females)

Research into other possible causes is ongoing.

The four main types of leukemia#

Leukemia can develop suddenly, over days or weeks (acute leukemia), or over months or years (chronic leukemia). It may involve either the myeloid or lymphoid cells, and is named for the type of blood cell affected. The four main types are:

• acute lymphocytic leukemia (ALL)
• chronic lymphocytic leukemia (CLL)
• acute myeloid leukemia (AML)
• chronic myeloid leukemia (CML)

Acute lymphocytic leukemia (ALL) affects lymphocytes, a type of white blood cell whose main role is to protect the body from infection, so they can no longer work properly. This can lead to serious infection. It also causes many abnormal lymphocytes to be made, which crowd out normal red blood cells and platelets. ALL is the most common type in children and is rare in adults.

Chronic lymphocytic leukemia (CLL) also affects the lymphocytes but develops more slowly than ALL. Most people with CLL are not aware they have it and may only be diagnosed during an examination for another problem. CLL affects adults and does not occur in children.

Acute myeloid leukemia (AML) mainly affects the myeloid cells known as granulocytes, which search for infectious invaders in the blood and nearby tissue. In AML, too many young myeloid cells are produced and there are not enough mature ones. The young myeloid cells can block blood vessels. AML mainly affects adults but can occur in children and adolescents.

Chronic myeloid leukemia (CML) involves too many mature myeloid cells that do not function properly. It differs from the more common types because it has two stages: in the first, abnormal cells slowly multiply; in the second, the disease changes quickly and becomes much like AML. CML can occur at any age but is uncommon under the age of 20.

Symptoms of leukemia#

Symptoms may vary slightly depending on the type and stage. With acute leukemia they usually appear quite suddenly. People with chronic leukemia often have many of the same symptoms, but these tend to develop over months or years. They can include:

• weakness, tiredness and looking “washed out”
• regular infections and high temperatures
• bleeding easily, including from the gums and nose
• low red blood cell counts (anemia) causing breathlessness and tiredness (more common in later stages of CLL)
• bruising easily with no obvious cause
• pain in the bones and joints
• weight loss
• swollen lymph glands
• abdominal discomfort due to an enlarged spleen

Most people with these symptoms will not have leukemia and are more likely to have a much less serious problem, such as an infection. Even so, it is important to see your doctor if you have symptoms that persist.

Diagnosis#

Tests that help diagnose leukemia may include:

• Blood tests, which check for large numbers of abnormal white blood cells
• Bone marrow biopsy, in which a small amount of bone marrow is taken from the hip bone with a needle and examined under a microscope to help identify the type of leukemia
• Lumbar puncture, in which fluid is removed with a needle from a space between the bones in the back and examined under a microscope

If these tests show that you have leukemia, you may need further blood and bone marrow tests, as well as scans such as a CT, PET scan or MRI. Results can take a few days to come back, and it is natural to feel anxious while you wait. It can help to talk with a close friend or relative, or with a specialist nurse, about how you are feeling.

Treatment#

Most children and many adults with acute leukemia can expect to be cured, and for most people chronic leukemia can be successfully managed for long periods. Treatment depends on the type of leukemia and may include:

• Chemotherapy – medication that destroys or slows the growth of fast-growing cancer cells. It is usually given intravenously, but may sometimes be given as tablets. Treatment for acute leukemia may mean several weeks in hospital, while others can stay at home with regular check-ups and further treatment.
• Stem cell transplant – a transplant allows much higher doses of chemotherapy than usual, which can improve the chance of cure or prolong remission for some types. The high-dose chemotherapy, sometimes given with total body irradiation (TBI), destroys the bone marrow and stem cells. Afterwards you are given an infusion of either your own stem cells (autologous transplant) or stem cells from a donor (allogeneic transplant).
• CAR T-cell therapy – a type of immunotherapy and gene therapy that changes the genetic make-up of some of your own T-cells (immune cells) so they recognize proteins on the surface of cancer cells and attempt to kill them.
• Biological therapy (immunotherapy) – the use of substances naturally produced within the body to encourage the immune system to fight disease, such as interferon and growth factors.
• Radiotherapy – may be used for different types to help control symptoms as part of intensive treatment, or to treat cancer that has spread to the brain or spinal cord.
• Steroids – for some types, treatment works better when steroids are given alongside chemotherapy.
• All-trans-retinoic acid – a form of vitamin A used to treat a type of acute myeloid leukemia called acute promyelocytic leukemia (APML), usually taken as tablets with chemotherapy.
• Supportive care – prevents and treats symptoms, for example with blood and platelet transfusions.

Some complementary therapies, used alongside conventional treatment, can help you feel better and improve quality of life. Others may be less helpful, and in some cases may be harmful, so discuss any you are considering with your medical team.

All treatments have side effects, which vary with the type of treatment. Many are temporary, but some may be permanent, and your doctor will explain the possible side effects before treatment begins.

Research and clinical trials#

Early detection and better treatment have improved survival for people with leukemia, and research is ongoing. Clinical trials can test the effectiveness of promising new treatments or new ways of combining cancer treatments. Always discuss your treatment options with your doctor, as there may be a clinical trial to suit your type of leukemia.

Living with leukemia#

Leukemia and its treatment can affect the way you feel about your body, your relationships, and the way you express yourself sexually. These changes can be upsetting, and your medical team should discuss them with you before and during treatment. It often helps to be as open as possible with a partner about how you are feeling, and you can ask your doctor for a referral to a counselor if you would like further support.

Caring for someone with leukemia can also be difficult and emotional, and support is available for carers.

When a cure isn’t possible#

If leukemia is diagnosed at a later stage, the cancer may have spread to the point where a cure is no longer possible. Treatment then focuses on improving quality of life by relieving symptoms, which is called palliative treatment. Medication can be used to relieve pain, nausea and vomiting.

Key points#

• Leukemia causes large numbers of abnormal white blood cells to be produced, which can crowd the bone marrow.
• There are four main types of leukemia: ALL, CLL, AML and CML.
• The cause of most cases is unknown, but several risk factors can increase the chance of developing it.
• Treatment depends on the type and may include chemotherapy, stem cell transplant and other therapies.
• Many people can be cured or have their leukemia managed for long periods, and research is ongoing.

Where to get help#