Leukemia

What is leukemia?

Leukemia is a type of blood cancer. It is characterized by an uncontrolled growth of abnormal blood cells in the bone marrow, where most of our blood is made. Usually, leukemia cells are white blood cells that are still developing.

When blood cells form, they go through several stages before they mature. Mature blood cells include white blood cells, red blood cells and platelets.

Each of these types of blood cells begins as hematopoietic stem cells. They then develop into either myeloid cells, which develop into red blood cells, some types of white blood cells, or platelets, or lymphoid cells, which develop into certain types of white blood cells.

If you have leukemia, then one of the developing blood cells has begun to multiply in an uncontrolled way. This is caused by a mutation in the DNA of the cell which usually controls its growth. The abnormal cells take over space inside the bone marrow where other cells are developing into healthy red and white blood cells and platelets.

Are there different types of leukemia?

There are four main types of leukemia. Leukemia is classified based on how fast it progresses and whether the leukemia cells have come from lymphoid cells or myeloid cells.

Leukemia classification

Disease progression:

Acute leukemia: The cancerous cells divide quickly, and the disease progresses rapidly. Acute leukemia can make you very unwell within a matter of weeks and is a serious condition that requires immediate treatment.

Chronic leukemia: This type of leukemia usually progresses a lot slower than acute leukemia. Sometimes, symptoms are not noticeable for years. Chronic leukemia is more common among adults.

Cell type:

Lymphocytic leukemia: This type of leukemia develops in lymphoid cells, the cells which develop into white blood cells, and are part of our immune system.

Myeloid leukemia: This type of leukemia develops in myeloid cells, the cells which develop into red blood cells, platelets, and white blood cells.

Types of leukemia

Acute lymphocytic leukemia: This is the most common type of leukemia in children, teenagers and young adults up to age 39. It can affect adults of any age.

Acute myelogenous leukemia: This is the most common type of acute leukemia in adults. It is more common among adults over 65. It can also occur in children.

Chronic lymphocytic leukemia: This is the most common type of chronic leukemia in adults. It is most common among those over 65.

Chronic myelogenous leukemia: This type of leukemia can affect adults of any age but is more common among those over 65. It is rare among children.

What are the symptoms of leukemia?

When leukemia cells grow in the bone marrow, they leave little space for healthy blood cells to develop. With fewer red blood cells, white blood cells, and platelets, your organs and tissues aren’t getting enough oxygen to function properly. Your body isn’t able to fight infections and blood clots can’t form when needed.

Symptoms of leukemia can include:

• Tiredness or fatigue
• Fever
• Frequent infections
• Pale skin
• Bone and joint pain
• Shortness of breath
• Swollen lymph nodes
• Bruising easily
• Pain under the ribs on the left side.

Symptoms of leukemia may depend on the type, for example, chronic leukemia may have no symptoms in the early stage.

Who is at risk of developing leukemia?

Anyone can get leukemia, but there are factors that may increase the risk. These include:

• Having had cancer treatments involving chemotherapy or radiation therapy.
• Having a history of smoking or exposure to secondhand smoke.
• Being exposed to certain industrial chemicals including benzene and formaldehyde.
• Having genetic disorders such as Down syndrome, neurofibromatosis, Schwachman-Diamond syndrome, and Klinefelter syndrome.
• Having a family history of leukemia.

How is leukemia diagnosed?

A number of diagnostic tests may be performed if your doctor suspects leukemia:

Physical examination: Your doctor will discuss your symptoms with you in detail and look for signs of swollen lymph nodes, and an enlarged liver or spleen. They may also look for a rash and inspect your gums for swelling or bleeding.

Blood test: A complete blood count (CBC) will detect abnormal levels of white blood cells, red blood cells and platelets. The blood sample may also be examined in a laboratory for markers which may indicate the presence of leukemia cells.

Bone marrow biopsy: This may be done if a high white blood cell count is found. Fluid is taken from the bone marrow via a long needle, which is then tested for leukemia cells.

Imaging tests: A chest X-ray, MRI or CT scan may be ordered if your doctor suspects leukemia has affected your organs, tissue or bones.

Lumbar puncture: A sample of spinal fluid is taken to see if leukemia has spread to the fluid surrounding the brain and spinal cord.

How is leukemia treated?

The treatment you receive for leukemia will depend on the type of leukemia you have, your overall health, your age and whether it has spread to other parts of the body. Treatment may include:

Chemotherapy: The most common leukemia treatment, chemotherapy involves chemicals to kill leukemia cells, or to stop them from multiplying. Chemotherapy is given intravenously, as an injection, or as a pill. Often, you will receive a combination of chemotherapy drugs.

Immunotherapy: This involves giving drugs which boost your body’s immune response to fight leukemia. The drugs help your immune system to identify leukemia cells and make more immune cells to fight them.

Targeted therapy: This involves drugs which target the parts of leukemia cells that are causing them to override healthy blood cells. Targeted therapies can kill leukemia cells, prevent leukemia cells from multiplying or cut off their blood supply.

Radiation therapy: Strong energy beams are directed at the area affected by cancer to kill leukemia cells. Radiation can also be distributed over the whole body.

Hematopoietic cell transplant: Also known as a bone marrow transplant or stem cell transplant, treatment involves replacing cancerous cells which have been killed by chemotherapy or radiotherapy with healthy new hematopoietic cells. These healthy cells may be removed from you before you undergo treatment with chemotherapy or radiotherapy, or they may come from a donor.