Acute Lymphoblastic Leukemia

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.

In ALL, too many stem cells develop into lymphoblasts and do not mature to become lymphocytes. These lymphoblasts are called leukemia cells. The leukemia cells do not work like normal lymphocytes and are not able to fight infection very well. Also, as the number of leukemia cells increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may lead to infection, anemia, and easy bleeding.

There are different subgroups of ALL based on the following:

  • Whether the type of blood cell that is affected looks more like a B lymphocyte or a T lymphocyte.
  • The age of the child at diagnosis. For example, whether the child is younger than one year, one year to 10 years old, or older than 10 years (teenager).
  • Whether there are certain changes in the chromosomes. Philadelphia chromosome -positive ALL is one type of chromosome change that may occur.

 

Stages of Acute Lymphoblastic Leukemia

 

In childhood ALL, risk groups are used instead of stages. Because ALL is a disease of the blood cells, it has already spread throughout the body at diagnosis. There is no staging system for ALL. Risk groups are used to plan treatment. Risk groups are described as:

  • Standard (low) risk: Includes children aged 1 to 9 years who have a white blood cell count of less than 50,000/µL at diagnosis.
  • High risk: Includes children younger than 1 year or older than 9 years and children who have a white blood cell count of 50,000/µL or more at diagnosis.

Other factors that affect the risk group include the following:

  • Whether the leukemia cells formed from B lymphocytes or T lymphocytes.
  • Whether there are certain changes in the chromosomes of the lymphocytes.
  • How quickly the leukemia responds to initial therapy.

It is important to know the risk group in order to plan treatment.

 

Treatment of Acute Lymphoblastic Leukemia

 

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.

Bone marrow biopsy and aspirates are done throughout all phases to see how well the leukemia is responding to treatment. Treatment called central nervous system (CNS) sanctuary therapy is usually given during induction therapy and consolidation/intensification therapy and is often given during maintenance therapy. Because most anticancer drugs given by mouth or injected into a vein to kill leukemia cells may not reach leukemia cells in the CNS (brain and spinal cord), the leukemia cells are able to find “sanctuary” (hide) in the CNS. Certain anticancer drugs, intrathecal chemotherapy, and radiation therapy are able to reach leukemia cells in the CNS and are given to kill the leukemia cells and prevent the cancer from recurring (coming back). CNS sanctuary therapy is also called CNS prophylaxis because it is given to stop leukemia cells from growing in the CNS.

 

Treatment types include the following:

 

  • Chemotherapy
  • Radiation therapy
  • Chemotherapy with stem cell transplant
  • Targeted therapy

 

New types of treatment are being tested in clinical trials

 

Patients may want to think about taking part in a clinical trial. Patients can enter clinical trials before, during, or after starting their cancer treatment.

Search for clinical trials in Georgia.

Adapted from the National Cancer Institute's PDQ Database: http://www.cancer.gov/cancertopics/pdq/treatment/childALL/Patient/page1. (Accessed July 2016)