Overview

Childhood acute lymphoblastic leukemia (also called acute lymphocytic leukemia or ALL) is a cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if it is not treated. It is the most common type of cancer in children.

Normally, the bone marrow makes blood stem cells (immature cells) that develop into mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell.

The myeloid stem cell develops into one of three types of mature blood cells:

• Red blood cells that carry oxygen and other materials to all tissues of the body.

• Platelets that help prevent bleeding by causing blood clots to form.

• Granulocytes (white blood cells) that fight infection and disease.

The lymphoid stem cell develops into a lymphoblast cell and then into one of three types of lymphocytes (white blood cells):

• B lymphocytes that make antibodies to help fight infection.

• T lymphocytes that help B lymphocytes make the antibodies that help fight infection.

• Natural killer cells that attack cancer cells and viruses.

There are subgroups of childhood ALL.

Four of the subgroups of ALL are based on the type of blood cell that is affected, whether there are certain changes in the chromosomes, and age at diagnosis:

• T cell ALL.

• Philadelphia chromosome positive ALL.

• ALL diagnosed in an infant.

• ALL diagnosed in children who are aged 10 and older and adolescents (teenagers).

Possible signs of childhood ALL include fever and bruising.

These and other symptoms may be caused by childhood ALL. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• Fever

• Easy bruising or bleeding.

• Petechiae (flat, pinpoint spots under the skin caused by bleeding).

• Bone or joint pain

• Painless lumps in the neck, underarm, stomach, or groin.

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.

• Complete blood count (CBC) with differential: A procedure in which a sample of blood is drawn and checked for the following:

• The number of red blood cells and platelets.

• The number and type of white blood cells.

• The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.

• The portion of the sample made up of red blood cells.

The treatment of childhood ALL usually has 3 phases.
The treatment of childhood ALL is done in phases:

• Induction therapy: This is the first phase of treatment. Its purpose is to kill the leukemia cells in the blood and bone marrow. This puts the leukemia into remission. This is also called the remission induction phase.

• Consolidation /intensification therapy: This is the second phase of therapy. It begins once the leukemia is in remission. The purpose of consolidation/intensification therapy is to kill any remaining leukemia cells that may not be active but could begin to regrow and cause a relapse.

• Maintenance therapy: This is the third phase of treatment. Its purpose is to kill any remaining leukemia cells that may regrow and cause a relapse. Often the cancer treatments are given in lower doses than those used for induction and consolidation/intensification therapy. This is also called the continuation therapy phase