Leukemia can refer to all cancers affecting the white blood cells. How the cancer spreads can depend on the type of leukemia and how aggressive it is.
Leukemia is a cancer of the blood cells. There are several broad categories of blood cells, including red blood cells (RBCs), white blood cells (WBCs), and platelets. Generally, leukemia refers to cancers of the WBCs.
WBCs are a vital part of your immune system. They protect your body from invasion by:
- bacteria
- viruses
- fungi
- abnormal cells
- foreign substances
In leukemia, the WBCs do not function like normal WBCs. They divide too quickly and eventually crowd out normal blood cells.
This article provides a more in-depth look at leukemia, including how it develops, symptoms, types, treatment, and survival rates.
Leukemia begins in your bone marrow. This is the spongy tissue located in your bones where your body’s blood cells are formed.
Blood cells go through multiple stages before reaching maturity. Blood cells start out as hematopoietic stem cells. These stem cells then develop into myeloid cells or lymphoid cells.
Myeloid cells develop into red blood cells, platelets, and certain types of white blood cells: basophils, eosinophils and neutrophils. Lymphoid cells develop into other types of white blood cells: lymphocytes and natural killer cells.
Mature stem cells that develop normally serve important bodily functions. For example:
- RBCs carry oxygen and other important materials to tissues and organs.
- WBCs fight infection.
- Platelets help your blood clot.
If you have leukemia, a developing stem cell in your bone marrow begins to multiply out of control.
When this happens, the abnormal cells — called leukemia cells — start to take over the space inside your bone marrow. As they multiply, they crowd out other developing healthy cells.
Having too many leukemia cells in your bone marrow is harmful for the following reasons:
- The developing RBCs, WBCs, and platelets have very little space to mature and multiply in your bone marrow because leukemia cells are overtaking them.
- When fewer RBCs are made and released into your bloodstream, your body’s organs and tissues don’t get the oxygen they need to function properly.
- When fewer WBCs are made and released into your bloodstream, your body’s ability to fight infections is impaired.
- When fewer platelets are made and released into your bloodstream, it affects your body’s ability to form blood clots when needed.
Leukemia can be classified by how quickly it progresses or by the type of blood cell it develops from.
Speed of progression
- Acute leukemia: Acute leukemias develop quickly. You’ll typically feel sick within weeks of the leukemia cells forming. Acute leukemia is life threatening and requires immediate treatment. It’s the most common cancer in children.
- Chronic leukemia: Chronic leukemias progress slowly, and early symptoms may be mild. The leukemia cells develop slowly and often function as the cells they were meant to become. People with chronic leukemia may not have noticeable symptoms for years. This type of leukemia is more common in adults.
Type of blood cell affected
Leukemia is also classified according to the type of cell that it developed from:
- Myeloid or myelogenous leukemia: Leukemia that develops from myeloid cells is called myeloid or myelogenous leukemia.
- Lymphocytic leukemia: Leukemia that develops from lymphoid cells (lymphocytes) is called lymphocytic leukemia.
There are four main types of leukemia:
Acute myeloid leukemia (AML)
Acute myeloid leukemia (AML) can occur in children and adults. According to the Surveillance, Epidemiology, and End Results Program of the
AML is the most common form of leukemia. The 5-year relative survival rate for AML is 31.9%.
Acute lymphocytic leukemia (ALL)
Acute lymphocytic leukemia (ALL) occurs
Chronic myeloid leukemia (CML)
Chronic myeloid leukemia (CML) affects mostly adults. About 9,000 new cases of CML are diagnosed annually, according to the
Chronic lymphocytic leukemia (CLL)
Chronic lymphocytic leukemia (CLL) is most likely to affect people over age 55 years. It’s very rarely seen in children. According to the
Hairy cell leukemia is a very rare subtype of CLL. Its name comes from the appearance of the cancerous lymphocytes under a microscope.
Researchers do not know what exactly causes leukemia. However, there are some risk factors for developing this cancer. Some of these risk factors include:
- a family history of leukemia
- smoking, which increases your risk of developing AML
- genetic disorders such as Down syndrome
- blood disorders such as myelodysplastic syndrome, which is sometimes called “preleukemia”
- previous treatment for cancer with chemotherapy or radiation
- exposure to high levels of radiation
- exposure to chemicals such as benzene
How common is leukemia?
In 2021, leukemia accounted for
While leukemia can affect anyone, including children, it’s more common in people who are:
- 65 to 74 years old
- male
- white
The symptoms of leukemia may include:
- excessive sweating, especially at night (night sweats)
- fatigue and weakness that do not go away with rest
- unintentional weight loss
- bone pain and tenderness
- painless, swollen lymph nodes, especially in the neck and armpits
- enlarged liver or spleen
- red spots on the skin, called petechiae
- bleeding easily and bruising easily
- fever or chills
- frequent infections
Leukemia can also cause symptoms in organs that have been infiltrated or affected by the cancer cells. For example, if the cancer spreads to the central nervous system, it can cause:
- headaches
- nausea and vomiting
- confusion
- loss of muscle control
- seizures
How the cancer spreads depends on the type of leukemia and how aggressive it is. Parts of your body that leukemia can spread to
A doctor may suspect leukemia if you have concerning symptoms or certain risk factors. They will begin the diagnostic process by reviewing your complete medical history and performing a physical examination.
However, a physical exam cannot fully diagnose leukemia. Instead, doctors make a diagnosis using:
- Blood tests: A number of different blood tests can be used to diagnose leukemia. A complete blood count determines the number of RBCs, WBCs, and platelets in the blood. Looking at your blood under a microscope can also determine whether the cells have an abnormal appearance.
- Tissue biopsies: Tissue biopsiescan be taken from the bone marrow or lymph nodes to look for evidence of leukemia. These small samples can identify the type of leukemia and its growth rate. Biopsies of other organs, such as the liver and spleen, can show whether the cancer has spread.
- Imaging tests: Imaging tests such as chest X-rays, ultrasounds, CT scans, MRIs, and PET scans can help doctors determine whether leukemia cells have affected the bones or organs such as the kidneys, brain, or lymph nodes.
A diagnosis of leukemia is typically confirmed using a bone marrow biopsy and aspiration.
How do doctors stage leukemia?
Once a doctor diagnoses leukemia, they then determine its stage. Staging finds out how much the cancer has spread and progressed. It helps a doctor determine your outlook.
AML and ALL are staged based on how cancer cells look under a microscope and the type of cells involved. ALL and CLL are staged based on the WBC count at the time of diagnosis.
The presence of immature white blood cells, or myeloblasts, in the blood and bone marrow is also used to stage AML and CML.
How do doctors monitor and assess the progression of leukemia?
Doctors can use a number of
- Flow cytometry examines the DNA of the cancer cells and determines their growth rate.
- Liver function tests show whether leukemia cells are affecting the liver.
- Lumbar puncture is performed by inserting a thin needle between the vertebrae of your lower back. This allows your doctor to collect spinal fluid and determine whether the cancer has spread to the central nervous system.
- Imaging tests, such as X-rays, ultrasounds, and CT scans, help doctors look for any damage to other organs that’s caused by the leukemia.
Hematologist-oncologists usually treat leukemia. These are doctors who specialize in blood disorders and cancer. The type of treatment used depends on:
- the type of leukemia
- the stage of leukemia
- a person’s overall health
- whether a person has any other medical conditions
Some forms of leukemia grow slowly and do not need immediate treatment. However, treatment for leukemia usually involves one or more of the
- Chemotherapy: Chemotherapy uses drugs to kill leukemia cells. Depending on the type of leukemia, you may take either a single drug or a combination of different drugs.
- Radiation therapy: Radiation therapy uses high energy radiation to damage leukemia cells and inhibit their growth. Radiation can be applied to a specific area or to your entire body.
- Stem cell transplantation: A stem cell transplant replaces diseased bone marrow with healthy bone marrow, either your own (called autologous transplantation) or from a donor (called allogeneic transplantation). This procedure is also called a bone marrow transplant.
- Biological or immune therapy: Biological or immune therapy uses treatments that help your immune system recognize and attack cancer cells.
- Targeted therapy:
Targeted therapyTrusted Source uses medications that take advantage of vulnerabilities in cancer cells. For example, imatinib (Gleevec) is a targeted drug commonly used against CML.
The long-term outlook for people who have leukemia depends on the type of cancer they have and their stage at diagnosis. The sooner leukemia is diagnosed and the faster it’s treated, the better your chance of recovery.
Some factors, like older age, past history of blood disorders, and chromosome mutations, can also affect outlook.
Survival rates by type of leukemia
| Type | Age range | Survival rate |
|---|---|---|
| acute myeloid leukemia (AML) | This type of leukemia is most common in older adults, but it can be diagnosed at any age. Most deaths occur in people 65 to 84 years old. | The 5-year relative survival rate for all ages is about |
| acute lymphocytic leukemia (ALL) | This type of leukemia is mostly diagnosed in | Survival rates are pretty even across all ages. The relative survival rate for all ages is |
| chronic lymphocytic leukemia (CLL) | This form of leukemia mostly affects adults over 55 years old. | The 5-year relative survival rate for people of all ages with this form of leukemia is |
| chronic myeloid leukemia (CML) | This type of leukemia is also most prominent in adults over 55 years old. | The 5-year relative survival rate for all ages for this type of leukemia is about |
| chronic myelomonocytic leukemia (CMML) | Most cases occur in people 60 years old and over. It’s rare for CMML to be diagnosed in someone under 40. | • The • The subtype of this leukemia doesn’t only affect survival rates. It can also affect how likely you are to develop other types of cancer later on. |
Leukemia deaths have been falling
According to the NCI, the number of leukemia deaths has been falling on average
Relative survival rates include people of all ages and with all forms of leukemia. It’s not predictive of the outcome for any one person. Talk with your medical team to determine your specific outlook. Remember that each person’s situation is different.
Can you prevent leukemia?
According to the Canadian Cancer Society, you may lower your risk of leukemia by:
- not smoking
- maintaining a moderate body weight
- avoiding exposure to benzene and
formaldehydeTrusted Source
Is leukemia curable if caught early?
Diagnosing any cancer in its early stages can improve treatment success rates, and some leukemias can be cured.
Newer, more effective medications and treatments for leukemia are also increasing the amount of time people can live with the disease, even when it’s not caught early.
Recent figures from the National Cancer Institute report the 5-year survival rate for all types of leukemia is
Which type of leukemia is the most aggressive?
Acute myeloid leukemia (AML) is the most aggressive type of leukemia. It progresses rapidly and requires immediate treatment.
Chemotherapy is the primary treatment for AML. Its purpose is to kill as many leukemia cells in your body as possible and reduce the risk of recurrence (the cancer coming back).
What questions should I ask my healthcare team if I receive a diagnosis of leukemia?
It’s always a good idea to bring a list of questions and concerns to any meeting with your doctor. If you’ve recently received a diagnosis of leukemia, here are some questions to discuss with your doctor:
- What type and classification of leukemia do I have?
- What stage is my cancer in, and has it spread to other parts of my body?
- What symptoms should I expect to have from my cancer?
- What are my treatment options?
- What kind of side effects will occur with this treatment?
- Should I consider joining a clinical trial? Are there any you know of that are appropriate for my situation?
- How will treatment affect my daily life? Will I be able to continue working or attending school?
- What’s the likelihood that treatment will put my cancer into remission?
- Are there local support groups or supportive care groups that I can join?