Leukemia

Facts

Unlike many cancers, leukemia rarely forms solid tumors. Instead, leukemia is cancer of the bone marrow and blood. 

 

Bone marrow The soft, spongy material in the center of your bones that produces all your blood cells, such as white blood cells, red blood cells and platelets.

What is leukemia?

In people with leukemia, the bone marrow produces abnormal (leukemic) blood cells. 

  • The leukemic cells divide and multiply but don’t go through the normal process of maturing and eventually dying, like healthy blood cells do.
  • The underdeveloped leukemic cells can’t carry out their normal functions. 
  • They build up in your bone marrow and blood, crowding out normal, healthy blood cells that your body needs. 
  • Low levels of normal blood cells can lead to infection, anemia and excessive bleeding. 
  • The leukemic cells can travel around your body through your bloodstream and interfere with the function of your organs.
Anemia A condition in which the number of red blood cells is below normal. Bone marrow The soft, spongy material in the center of your bones that produces all your blood cells, such as white blood cells, red blood cells and platelets.

Understanding your bone marrow and blood

To understand leukemia, it helps to know the basics about your bone marrow and blood cells.

Bone marrow The soft, spongy material in the center of your bones that produces all your blood cells, such as white blood cells, red blood cells and platelets.
What are stem cells?

Stem cells are cells in your body that have the potential to turn into any kind of cell, such as a skin cell, liver cell, brain cell or blood cell. Stem cells that turn into blood cells are called hematopoietic stem cells, or blood stem cells. 

Stem cell A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.
Why are blood stem cells important?

When blood cells become old or damaged, they die, and blood stem cells produce new blood cells to replace them. Blood stem cells are mainly found in bone marrow (the soft, spongy tissue inside your bones), but some are also found in circulating blood.

Blood stem cells produce lymphoid stem cells and myeloid stem cells. 

  • Lymphoid stem cells produce lymphoblasts, which in turn produce several types of white blood cells. 
  • Myeloid stem cells produce myeloblasts, which in turn produce white blood cells, red blood cells and platelets.
Bone marrow The soft, spongy material in the center of your bones that produces all your blood cells, such as white blood cells, red blood cells and platelets. Platelet A tiny, disc-shaped piece of a cell that is found in the blood and spleen. Platelets help form blood clots to slow or stop bleeding and to help wounds heal. A tiny, disc-shaped piece of a cell that is found in the blood and spleen. Platelets are pieces of very large cells in the bone marrow called megakaryocytes. They help form blood clots to slow or stop bleeding and to help wounds heal. Having too many or too few platelets, or having platelets that do not work as they should, can cause problems. Checking the number of platelets in the blood may help diagnose certain diseases or conditions. Red blood cell A type of blood cell that carries oxygen in the body. Stem cell A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.
What do healthy blood cells do?

Healthy white blood cells, red blood cells and platelets are essential.

  • White blood cells fight infection.
  • Red blood cells carry oxygen from your lungs to other parts of your body and take carbon dioxide back to your lungs to be removed.
  • Platelets make your blood clot and slow or stop bleeding.

Bloodcells

Platelet A tiny, disc-shaped piece of a cell that is found in the blood and spleen. Platelets help form blood clots to slow or stop bleeding and to help wounds heal. A tiny, disc-shaped piece of a cell that is found in the blood and spleen. Platelets are pieces of very large cells in the bone marrow called megakaryocytes. They help form blood clots to slow or stop bleeding and to help wounds heal. Having too many or too few platelets, or having platelets that do not work as they should, can cause problems. Checking the number of platelets in the blood may help diagnose certain diseases or conditions. Red blood cell A type of blood cell that carries oxygen in the body.

Types

Leukemias are named for the type of blood stem cell — lymphoid or myeloid — that is affected and how quickly the disease develops and progresses. 

  • Acute leukemias grow rapidly, leading to symptoms, and they worsen quickly without treatment. 
  • Chronic leukemias are slower to develop.

There are four main types of leukemia in adults.

  • Acute lymphoblastic leukemia, also called acute lymphocytic leukemia or acute lymphoid leukemia
  • Acute myeloid leukemia, also called acute myelogenous leukemia or acute myelocytic leukemia
  • Chronic lymphocytic leukemia, also called chronic lymphoid leukemia or chronic lymphoblastic leukemia
  • Chronic myeloid leukemia, also called chronic myelogenous leukemia or chronic myelocytic leukemia

There are several other types of leukemia and related blood disorders, such as hairy cell leukemia and chronic myelomonocytic leukemia.

Stem cell A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells. Symptom A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. Some examples of symptoms are headache, fatigue, nausea and pain.

Classifying

Leukemias are further grouped into subtypes, phases and risk categories based on:

  • Chromosomal and molecular abnormalities in your leukemia cells
  • Whether you have had treatment
  • How your disease responds to treatment

Your doctor uses this information, along with other factors, such as your age, your general health and your sex, to plan your treatment and predict the outcome.

Symptoms of leukemia

For acute leukemia, many of the early signs are similar to the flu or other common, less serious diseases.

In the early stages, chronic leukemia usually doesn’t cause symptoms, and it may take years before symptoms develop.

Check with your doctor if you have any of these.

  • Flu-like symptoms, such as fever, sweats and body aches
  • Infections 
  • Pale skin
  • Fatigue, weakness, lack of energy or sleepiness
  • Shortness of breath
  • Easy bleeding or bruising
  • Red spots on your palate, ankles or skin
  • Unexplained weight loss
  • Pain or aches in your bones, joints, stomach, arms, legs or back
  • Swelling of your abdomen or the lymph nodes in your neck, underarm, abdomen or groin
Sign In medicine, a sign is something found during a physical exam or from a laboratory test that shows that a person may have a condition or disease. In medicine, a sign is something found during a physical exam or from a laboratory test that shows that a person may have a condition or disease. Some examples of signs are fever, swelling, skin rash, high blood pressure and high blood glucose. Symptom A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. Some examples of symptoms are headache, fatigue, nausea and pain.

Diagnosing leukemia

If your doctor suspects you may have leukemia, they will want to perform a thorough physical examination and talk with you about your medical history. During the exam, your doctor will check for signs of leukemia, such as swollen or enlarged lymph nodes or spleen.

An accurate diagnosis of leukemia requires several tests. You might have any or all of these:

  • Blood tests — to check the type, number, size, shape and appearance of blood cells (complete blood count and peripheral blood smear) and to see if leukemic cells are present, which type they are and whether they show signs of slow-growing or more aggressive disease (immunophenotyping, or flow cytometry)
  • Bone marrow tests — taking samples of bone marrow and a small piece of bone from your pelvis using a needle (bone marrow aspiration and biopsy) and checking them for leukemic cells. 
  • Chromosome tests — checking your blood or bone marrow cells for changes in chromosomes, such as an abnormal number of chromosomes or two chromosomes that have exchanged some DNA. These tests include cytogenetic analysis, fluorescent in situ hybridization and polymerase chain reaction.
  • Lumbar puncture — taking a sample of cerebrospinal fluid from your spine with a needle to check whether leukemia has spread to your spinal cord and brain.
  • Imaging tests — such as chest X-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI) scan or ultrasound to check whether leukemia is impacting other parts of your body.
Biopsy The removal of a sample of tissue or fluid that is examined to see whether cancer is present. This may be done with a large needle or through surgical removal of tissue or fluids. Bone marrow The soft, spongy material in the center of your bones that produces all your blood cells, such as white blood cells, red blood cells and platelets. Chest X-ray A type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease. An X-ray is a type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease. Chromosome Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes. Chromosome Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes. Computed tomography A procedure that uses a computer linked to an X-ray machine to make a series of detailed pictures of areas inside the body. The pictures are used to create three-dimensional (3-D) views of tissues and organs. A procedure that uses a computer linked to an X-ray machine to make a series of detailed pictures of areas inside the body. The pictures are taken from different angles and are used to create three-dimensional (3-D) views of tissues and organs. A dye may be injected into a vein or swallowed to help the tissues and organs show up more clearly. This scan may be used to help diagnose disease, plan treatment or find out how well treatment is working. Cytogenetic test The process of analyzing cells in a sample of tissue, blood, bone marrow or amniotic fluid to look for changes in chromosomes, including broken, missing, rearranged or extra chromosomes. The process of analyzing cells in a sample of tissue, blood, bone marrow or amniotic fluid to look for changes in chromosomes, including broken, missing, rearranged or extra chromosomes. Changes in certain chromosomes may be a sign of a genetic disease or condition or some types of cancer. Cytogenetic analysis may be used to help diagnose disease, plan treatment or find out how well treatment is working. Flow cytometry A laboratory method that measures the number of cells, the percentage of live cells and certain characteristics of cells in a sample of blood, bone marrow or other tissue. A laboratory method that measures the number of cells, the percentage of live cells and certain characteristics of cells (such as size and shape) in a sample of blood, bone marrow or other tissue. The presence of tumor markers, such as antigens, on the surface of the cells is also measured. The cells are stained with a light-sensitive dye, placed in a fluid and then passed one at a time through a beam of light. The measurements are based on how the stained cells react to the beam of light. Flow cytometry is used in basic research and to help diagnose and manage certain diseases, including cancer. Imaging In medicine, a process that makes pictures of areas inside the body. Imaging uses methods such as X-rays (high-energy radiation), ultrasound (high-energy sound waves) and radio waves. Lumbar puncture A procedure in which a thin needle called a spinal needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs. Also called spinal tap. Magnetic resonance imaging A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or X-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints and the inside of bones. Peripheral blood smear A procedure in which a sample of blood is viewed under a microscope to count different circulating blood cells (such as red blood cells, white blood cells or platelets) and see whether they look normal. Polymerase chain reaction A laboratory method used to make many copies of a specific piece of DNA from a sample. It allows very small amounts of DNA to be amplified so they can be detected. A laboratory method used to make many copies of a specific piece of DNA from a sample that contains very tiny amounts of that DNA. Polymerase chain reaction allows these pieces of DNA to be amplified so they can be detected. Polymerase chain reaction may be used to look for certain changes in a gene or chromosome, which may help find and diagnose a genetic condition or a disease, such as cancer. It may also be used to look at pieces of the DNA of certain bacteria, viruses or other microorganisms to help diagnose an infection. Sign In medicine, a sign is something found during a physical exam or from a laboratory test that shows that a person may have a condition or disease. In medicine, a sign is something found during a physical exam or from a laboratory test that shows that a person may have a condition or disease. Some examples of signs are fever, swelling, skin rash, high blood pressure and high blood glucose. Spleen An organ that is part of the lymphatic system. The spleen makes lymphocytes, filters the blood, stores blood cells and destroys old blood cells. It is on the left side of the abdomen near the stomach. Ultrasound A procedure that uses high-energy sound waves to look at tissues and organs inside the body. The sound waves make echoes that form pictures of the tissues and organs on a computer screen. A procedure that uses high-energy sound waves to look at tissues and organs inside the body. The sound waves make echoes that form pictures of the tissues and organs on a computer screen (sonogram). Ultrasound may be used to help diagnose diseases, such as cancer. It may also be used during pregnancy to check the fetus (unborn baby) and during medical procedures, such as biopsies. Also called ultrasonography.

How common is leukemia?

About 62,000 people are diagnosed with leukemia in the United States each year. More than 90 percent are adults over age 20.

What causes leukemia?

Doctors do not know what causes some blood cells to become leukemic. Often changes or mutations in specific genes or chromosomes are seen in people with leukemia.

For most people with leukemia, there are no obvious reasons why they developed the disease. Some factors that may increase risk include:

  • Being exposed to certain viruses, chemotherapy or radiation
  • Being exposed to certain chemicals, such as cigarette smoke, herbicides or pesticides
  • Having certain genetic conditions, such as Down syndrome
  • Having a family history of blood cancers or disorders

Race, ethnicity, sex and age also influence risk.

Keep in mind that most people who develop leukemia have no risk factors, and most people with the risk factors do not develop the disease.

Chemotherapy Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. It may be given alone or with other treatments. Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Chemotherapy may be given by mouth, injection, infusion or on the skin, depending on the type and stage of the cancer being treated. It may be given alone or with other treatments, such as surgery, radiation therapy or biologic therapy. Chromosome Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes. Gene The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.