What Is Leukemia?

Leukemia is cancer of the body's white blood cells. The disease occurs when the body overproduces abnormal white blood cells or immature white blood cells. These white blood cells are not able to do the work of normal white blood cells, which help fight infection and disease in the body.

Leukemia is the most common cancer in children under 15 years, but can also occur in adults older than 55 years. Leukemia can be either acute or chronic—acute leukemia is fast-acting and typically worsens quickly. Chronic leukemia progresses more slowly over time. Treatments and prognosis for patients with leukemia depend on whether the leukemia is acute or chronic, and on the type of blood cell affected by it.

Leukemia is categorized into groups, including:

  • Myeloid or lymphocytic: The type of white cell where the cancer first occurred–either the lymphocytes or the myeloblasts
  • Acute or chronic: Worsens quickly (acute) or worsens gradually (chronic) 

The four main types of leukemia include:

Northwestern Medicine offers multidisciplinary care for the diagnosis and treatment of leukemia, with teams of hematologist-oncologists, medical oncologists, radiation oncologists, and more to help patients with leukemia get the care they need.