Acute Lymphoblastic Leukemia Overview

A Common Childhood Cancer

Updated on August 19, 2022

Medically reviewed by Doru Paul, MD

Fact checked by Nick Blackmer

Acute lymphoblastic leukemia (ALL) is a type of leukemia that mostly affects children, although it can affect adults as well. It is also referred to as acute lymphocytic or acute lymphoid leukemia. ALL affects immature lymphocytes—a type of white blood cell—known as blasts.

Toddler wearing a bandana — Xavier_S / iStock

Overview

ALL is actually the most common cancer in children, responsible for around 25% of childhood cancers. More than 5,000 people develop ALL each year in the United States, with around 1,500 deaths, though more than 75% of those who die are adults.

This disease is one that progresses rather quickly and is characterized by a large number of immature white blood cells in the blood and bone marrow. While in the past this was a rapidly fatal disease, it is now largely survivable with chemotherapy.

The description of a cancer being both aggressive and survivable at the same time can be confusing for some people. Chemotherapy works by attacking the most rapidly dividing cells, so aggressive cancers respond better to chemotherapy than slow-growing cancers. And while this cancer occurs mostly in children, children often do much better than adults with the disease.

What Are Lymphoblasts?

Lymphoblasts are an immature form of the type of white blood cell known as lymphocytes. In the bone marrow, a process called hematopoiesis takes place, which basically means the formation of our immune and blood cells.

This process starts with a hematopoietic stem cell which can evolve along either the myeloid line (which then becomes a type of white blood cell known as a granulocyte, red blood cell, or platelet) or the lymphoid line. The lymphoblast is the “baby” in this process. Lymphoblasts can go on to become T lymphocytes (T cells), B lymphocytes (B cells), or natural killer cells (NK cells).

Causes

It’s not known exactly what causes ALL, but risk factors may include:

Some genetic conditions, such as Down syndrome and Klinefelter syndrome
Exposure to substances such as benzene
Prenatal exposure to x-rays
Exposure to treatments for cancer, including radiation therapy and chemotherapy
Some chromosomal changes or gene mutations

Symptoms

Because lymphoblasts are created in the bone marrow, all types of blood cells—including white blood cells, red blood cells, and platelets—can be affected. The white blood cells that are produced—even if greater than normal in number—do not work as well as usual and there is often a decreased number of other forms of blood cells.

Symptoms may include:

Fatigue and weakness
Pallor (pale skin)
Fever or night sweats
Frequent infections (this can be difficult to determine in children who normally get several infections each year)
Bruising and/or bleeding easily
Shortness of breath
Decrease in appetite and weight loss
Petechiae (skin spots that appear red and do not disappear when you put pressure on the skin)
Bone and joint pain, especially in the long bones
Painless enlarged lymph nodes in the neck, armpits, and groin
Tenderness of the upper abdomen due to enlarged liver or spleen

Diagnosis

ALL is usually first suspected based on an increased white blood cell count with an increased number of immature lymphocytes. Further tests done in the diagnostic process may include:

More blood tests
Bone marrow aspiration and biopsy
Imaging tests, such as computed tomography ot magnetic resonance imaging, to look for tumors, especially in the abdomen, chest, or spinal cord
Lumbar puncture (spinal tap) to look for the presence of cancer cells in the cerebrospinal fluid

Treatment

Unlike some cancers, chemotherapy for ALL is often done over a period of a few years, rather than a few weeks.

The treatment of ALL can be broken down into the following stages, but usually includes intensive chemotherapy (stem cell transplants and radiation therapy are sometimes a part of treatment as well):

Remission induction: When ALL is diagnosed, the first step is to lower the count of blasts and restore the production of normal cells in the bone marrow. This involves aggressive chemotherapy and is sometimes done as an inpatient. When this step is done, someone with ALL is usually in remission.
Remission consolidation: The next step is to take care of any cancer cells that have survived induction therapy.
Maintenance therapy: Even after this cancer is in remission, and further treatment has eliminated any lingering cancer cells, it can recur without further treatment. Maintenance therapy is designed to prevent recurrence of leukemia and result in long-term survival and may last two to three years.
Central nervous system (CNS) prophylaxis: If ALL is present in the cerebrospinal fluid, intrathecal chemotherapy is usually done, since most chemotherapy drugs do not cross the blood-brain barrier. For many patients who do not have CNS involvement, treatment (which may also include radiation therapy) is done to prevent cancer from showing up or recurring in the brain.

The prognosis for children is somewhat better than adults for ALL. About 98% of children achieve remission and about 85% of children will go on to long-term survival with the disease.

Support and Coping

In most cases, it is a child experiencing ALL, so support needs to be directed not only at the children living with ALL but also their parents. Learn as much as you can about the disease. Reach out for help. Treatment for leukemia is a marathon rather than a sprint and it can help to let some of the people offering help know that you don’t need it right away, but to please help out as time goes on.

Support for children with cancer has improved dramatically and camps for children coping with the disease now exist all over the country. These camps help kids feel like they aren’t missing out on what their peers without cancer are enjoying.

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