Understanding acute lymphoblastic leukemia

Leukemia is the most common form of cancer diagnosed in children and acute lymphoblastic leukemia, or ALL as it’s commonly called, is the most common type of leukemia. ALL is a cancer of the blood and bone marrow, and it affects the body's white blood cells (WBCs). Normally, these cells help fight infection and protect the body against disease. But in leukemia, these cells turn cancerous and multiply when they shouldn't, resulting in too many abnormal WBCs.

How is leukemia diagnosed?

There are a number of tests that doctors and other healthcare professionals may do to determine if a child has leukemia. The tests are usually done if the child has one or more symptoms that might suggest the presence of leukemia. These symptoms can include fever, bruising or bleeding, bone or joint pain, fatigue or weakness.

The following are some of the most commonly prescribed tests to determine the presence of leukemia and if it has spread:

Physical exam: the child’s doctor will do a complete physical exam, and record the child’s medical history as well.
Complete Blood Count (CBC): a sample of the child’s blood is taken to determine the numbers of red blood cells, platelets, white blood cells and hemoglobin in the blood, and check for abnormalities and imbalances in the blood.
Bone marrow aspiration and biopsy: the child undergoes a procedure whereby a hollow needle is inserted into their hipbone or breastbone to take a sample of bone and bone marrow. A pathologist then analyzes the sample to test for leukemia. Cell and tissue tests can also be done by taking samples from fluids or other tissues in the body.
Lumbar puncture: a procedure which involves placing a needle into the child’s spinal column to take a sample of fluid. This test is usually done on children who have been diagnosed with leukemia to help determine if it has spread to the brain and spinal cord.

What are the treatments?

How a child is treated for ALL depends on several important factors in the child’s diagnosis such as their age, and whether the leukemia cells began as B-lymphocytes or T-lymphocytes. The goal of treatment is to destroy cancer cells.

Treating ALL is done in phases and involves chemotherapy treatments and other forms of medication. The first step is induction therapy which is done to kill as many ALL cells as possible and aim for a complete remission of the leukemia. The next step is consolidation which involves more medication to reinforce the remission. This is followed by an interim maintenance phase which aims to maintain the remission. The next phase is delayed intensification, a process which aims to eliminate any leukemia cells that are still present in the child’s body and to prevent the leukemia form coming back. Finally there is the maintenance phase where the child receives medications aimed at maintaining remission for a long time.

Survival rates (i.e. five years disease free) for ALL are close to 90 per cent, a figure that has gone up significantly over the past few decades thanks to treatment advances.

Sources: www.childhoodcancer.ca [1], www.cancer.gov [2]