Leukemia is a type of cancer that affects white blood cells. Although leukemia can develop in children, there are several types of the condition that doctors also diagnose in adults.

The types of leukemia that can occur in adults include:

Leukemia can cause symptoms such as fatigue, weight loss, frequent infections, anemia, and bleeding or bruising easily.

In this article, we discuss in detail leukemia in adults, including its symptoms, diagnosis, and treatment.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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Leukemia is a type of cancer that affects blood-forming cells. Usually, it affects white blood cells.

All blood cells in the human body begin their life cycle as stem cells, which are present in a person’s bone marrow. As the blood cells mature, they go through different stages of development.

Leukemia occurs when one type of immature blood cell mutates and begins growing uncontrollably. The overgrowth of one type of blood cell crowds out the others, causing a range of symptoms.

Leukemia can develop at any age. Some types are more common in adults, while others develop more frequently in children and adolescents.

Doctors categorize leukemias based on two broad characteristics: how fast they grow and the type of blood-forming cell they affect.

Immature blood cells can be myeloid or lymphoid. Myeloid cells go on to become red blood cells, platelets, or specific types of white blood cell. Lymphoid cells have the potential to become other types of white blood cell.

Leukemia that affects myeloid cells is known as myeloid or myelogenous leukemia, while leukemia that affects lymphoid cells is known as lymphoid, lymphocytic, or lymphoblastic.

The types of leukemia most common in adults include:


CLL is the most common type of chronic leukemia in adults, and it rarely develops in children. It starts in lymphoid cells that go on to become lymphocytes, which are a type of white blood cell.

In this chronic, slow-growing form of leukemia, the cancerous cells typically build up gradually, with many people experiencing no symptoms for a few years. This can mean they do not require treatment.

Over time, the cancerous cells spread to other parts of the body. In some cases, CLL can become a more aggressive cancer that is challenging for doctors to treat.


AML is a fast-growing type of leukemia that involves myeloid cells. It usually affects cells that will eventually become white blood cells, but it can also affect immature red blood cells or platelets.

AML is the most common acute leukemia in adults. It accounts for half of leukemia diagnoses for people in their 20s.

While AML originates in the bone marrow, it can quickly spread to other parts of the body, such as the liver, lymph nodes, spleen, spinal cord, brain, or testicles.


Similarly to AML, CML affects myeloid cells. However, it grows slowly.

It can develop in anyone, but it mainly occurs in adults. The average age of diagnosis is 64 years.


ALL is most common in children, accounting for 80% of all cases. However, 20% of leukemia cases in adults fall into this category.

ALL is an aggressive, fast-growing type of cancer that affects lymphoid white blood cells.

Symptoms of leukemia in adults can vary depending on the type of leukemia a person has. People with chronic forms may not have many symptoms for some time.

Those who do may experience one or more of the following:

Some of the factors that can raise the risk of leukemia in adults include:

  • smoking
  • experiencing exposure to radiation or benzene
  • having previously undergone chemotherapy
  • having certain viral infections, such as human T-lymphotropic virus type-1
  • having a genetic syndrome, such as Down syndrome, Bloom syndrome, or Fanconi anemia
  • having a history of other blood disorders

The incidence of leukemia is higher among males than females, and the likelihood of developing leukemia increases with age.

To diagnose leukemia in adults, doctors will ask the person about their symptoms and may perform a physical examination to look for symptoms such as bruising.

They will then recommend diagnostic tests, such as:

  • a complete blood count, which can detect high or low levels of different blood cells
  • bone marrow biopsy and aspiration, which allows doctors to examine a small amount of bone marrow tissue
  • a blood smear, which doctors examine under a microscope for signs of cancer
  • flow cytometry, which analyzes single cells in a special machine

A doctor can diagnose leukemia if they find leukemic cells in the bone marrow samples.

To determine the type and stage of the cancer, they need to identify whether the cells are myeloid or lymphoid and what percentage of the bone marrow these cells make up.

Treatment for leukemia depends on the type a person has. Treatment options may include:

ALL requires immediate treatment in order to stop the leukemia from spreading. This may involve intensive chemotherapy, targeted drug treatment, and a stem cell transplant.

For most forms of AML, the main treatment is chemotherapy, sometimes alongside a targeted therapy drug. Surgery and radiation therapy are treatment options only for specific circumstances.

The primary form of treatment for CML is targeted therapy drugs. This includes tyrosine kinase inhibitors (TKIs), which have been a breakthrough in CML treatment. TKIs reduce the progression of the disease and can control CML long term, causing fewer side effects than chemotherapy.

People with CLL may not require treatment, or they may not need it for a long time. Some people survive for just as long as the general population. There are drugs that reduce the impact the condition has and control its symptoms. However, there is no cure aside from stem cell transplantation.

Individuals should seek guidance from a healthcare professional if they experience any of the symptoms that could indicate leukemia.

Particularly concerning symptoms include:

  • anemia, which causes symptoms such as fatigue, weakness, and heart palpitations
  • frequent or severe infections
  • bruising more easily than normal
  • excessive bleeding, such as severe nosebleeds
  • unusually heavy periods

Leukemia is a form of cancer that affects blood-forming cells present in the bone marrow. It can affect either myeloid or lymphoid cells, and it can grow quickly or slowly. Doctors use these characteristics to categorize the type of leukemia a person has.

In adults, the most common type of leukemia is CLL. Acute or fast-growing types are also possible.

Leukemia can spread from the bone marrow into the bloodstream, allowing it to move to other parts of the body.

Treatment options vary, but they may include chemotherapy, targeted drugs, immunotherapy, or stem cell transplants.