Leukemia

How leukemia starts

Leukemia starts inside immune cells in the bone marrow. Bone marrow is the soft inner center of certain bones, where new blood cells are made.

At first, the leukemia cells multiply inside the bone marrow. As these cells build up, they crowd out the healthy cells. When this happens, leukemia cells can spill into the bloodstream, and your bone marrow can have a tough time making enough healthy cells. This can cause symptoms like low energy, bone pain, infections, easy bleeding, or bruising.

Sometimes, leukemia spreads to other parts of the body, such as the lymph nodes, spleen, liver, central nervous system (brain and spinal cord), testicles, or other organs.

Types of leukemia

Leukemia types are typically grouped based on how quickly the cancer grows and the type of blood cells it starts in. Knowing about the different types can help you better understand your diagnosis and treatment options.  

Most common types

• Acute lymphocytic leukemia (ALL)
• Acute myeloid leukemia (AML)
• Chronic lymphocytic leukemia (CLL)
• Chronic myeloid leukemia (CML)

Acute or chronic

• Acute leukemias grow quickly and usually need treatment soon after diagnosis.
• Chronic leukemias often grow more slowly. They may not need treatment right away.

Lymphoid or myeloid

• Lymphoid leukemias (also called lymphocytic) start in white blood cells called lymphocytes.
• Myeloid leukemias (also called myelogenous) start in other blood-forming cells in the bone marrow.

There are other, less common types of leukemia as well. Ask your cancer care team to explain the exact type you have and what it means for your treatment and care.

Features and symptoms

How leukemia is found

Leukemia is often found when a blood test called a complete blood count (CBC) shows abnormal results. Sometimes, this blood test is done because a person has symptoms. But abnormal results can also be found during a blood test done for another reason, even when you have no symptoms and feel well.

If your healthcare team suspects leukemia, they will probably need to do more tests before they know for sure.

Along with the complete blood count, these tests could also include:

• Blood smear or peripheral blood smear: A small drop of blood is collected from a vein in your arm or by doing a finger prick. Special dyes, such as methylene blue, are added to the blood sample to make blood cells easier to see under a microscope. The microscope is used to check the number, size, and shape of blood cells in the sample.
• Bone marrow biopsy and aspiration: A small sample of bone marrow is removed and checked for leukemia cells. The sample is often taken from your hip bone. Aspiration removes a sample of the liquid part of the bone marrow. Biopsy removes a sample of the solid part.
• Flow cytometry: Tests are done on blood and bone marrow samples to help identify the exact type of leukemia.
• Biomarker and tumor marker testing: Testing is done on blood and bone marrow samples to look for gene or chromosome changes in leukemia cells. These results can help your cancer care team plan the best treatment options.

Learn more about each leukemia type

Find detailed information about symptoms, diagnosis, treatment, and survivorship.