Childhood acute lymphoblastic leukemia (also called acute
lymphocytic leukemia or ALL) is a disease in which too many
underdeveloped lymphocytes are found in a child's blood and bone
marrow. Lymphocytes are infection-fighting white blood cells. ALL
is the most common form of leukemia in children, and the most
common kind of childhood cancer.
Lymphocytes are made by the bone marrow and by other organs of
the lymph system. The
is the spongy tissue
inside the large bones in the body. The bone marrow makes:
- Red blood cells (which carry oxygen and other materials to all
tissues of the body)
- White blood cells (which fight infection)
- Platelets (which make the blood clot)
Normally, the bone marrow makes cells called
Blasts develop (mature) into several different types of blood cells
that have specific jobs to do in the body.
The lymph system is made up of thin tubes that branch, like
blood vessels, into all parts of the body. Lymph vessels carry
, a colorless, watery fluid that contains lymphocytes.
Along the network of vessels are groups of small, bean-shaped
. Clusters of lymph nodes are found
in the underarm, pelvis, neck, and abdomen. The
organ in the upper abdomen that makes lymphocytes and filters old
blood cells from the blood), the
(a small organ
beneath the breastbone), and the
(an organ in the
throat) are also part of the lymph system.
Lymphocytes fight infection by making substances called
. Antibodies attack germs and other harmful
bacteria in the body. In ALL, the developing lymphocytes become too
numerous and do not mature. These immature lymphocytes are then
found in the blood and the bone marrow. They also collect in the
lymph tissues and make them swell. Lymphocytes may crowd out other
blood cells in the blood and bone marrow. If your child's bone
marrow cannot make enough red blood cells to carry oxygen, your
child may have anemia. If your child's bone marrow cannot make
enough platelets to make the blood clot normally, your child may
bleed or bruise easily. The cancerous lymphocytes can also invade
other organs, the spinal cord, and the brain.
Leukemia can be
(progressing quickly with many
immature cancer cells) or
(progressing slowly with
more mature-looking leukemia cells). Acute lymphoblastic leukemia
progresses quickly, and can occur in both children and adults.
Treatment is different for adults than it is for children.
Early signs of ALL may be similar to those of the flu or other
common diseases, such as:
- A fever that won't go away
- Feeling weak or tired all the time
- Aching bones or joints
- Swollen lymph nodes
If your child has symptoms of leukemia, his or her doctor may
order blood tests. These blood tests are used to count the number
of each of the different kinds of blood cells. If the results of
the blood tests are not normal, a
bone marrow biopsy
performed. During this test, a needle is inserted into a bone in
the hip and a small amount of bone marrow is removed and examined
under the microscope. This helps the doctor to determine what kind
of leukemia your child has and plan the best treatment.
Your child's doctor may also do a
. A needle is
inserted through the back to remove a sample of the fluid that
surrounds the brain and spine. The fluid is then examined under a
microscope to see if leukemia cells are present.
Your child's chance of recovery (prognosis) depends on:
- Your child's age at diagnosis
- The number of white blood cells in the blood (the white blood
cell count) at diagnosis
- How far the disease has spread
- The biologic characteristics of the leukemia cells
- How well the leukemia cells respond to treatment.
There is no staging for childhood acute lymphoblastic leukemia.
The treatment depends on age, the results of laboratory tests, and
whether or not the patient has been previously treated for
Untreated acute lymphoblastic leukemia (ALL) means that no
treatment has been given except to reduce symptoms. There are too
many white blood cells in the blood and bone marrow, and there may
be other signs and symptoms of leukemia.
Remission means that treatment has been given and the number of
white blood cells and other blood cells in the blood and bone
marrow is normal. There are no signs or symptoms of leukemia.
Recurrent disease means that the leukemia has come back
(recurred) after going into remission. Refractory disease means
that the leukemia failed to go into remission following
There are treatments for all patients with childhood acute
lymphoblastic leukemia (ALL). The primary treatment for ALL is
chemotherapy. Radiation therapy may be used in certain cases. Bone
marrow transplantation is being studied in clinical trials.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy
drugs may be taken by mouth, or may be put into the body by a
needle in a vein or muscle. Chemotherapy is called a systemic
treatment because the drug enters the bloodstream, travels through
the body, and can kill cancer cells throughout the body. For ALL,
chemotherapy drugs may sometimes be injected (usually through the
spine) into the fluid that surrounds the brain and spinal cord.
This is known as
Radiation therapy uses x-rays or other high-energy rays to
kill cancer cells and shrink tumors. Radiation for ALL usually
comes from a machine outside the body (external beam radiation
Bone marrow transplantation
Bone marrow transplantation is a newer type of treatment.
First, high doses of chemotherapy with or without radiation therapy
are given to destroy all of the bone marrow in the body. Healthy
marrow is then taken from another person (a donor) whose tissue is
the same as or almost the same as the patient's. The donor may be a
twin (the best match), a brother or sister, or another person not
related to the patient. The healthy marrow from the donor is given
to the patient through a needle in a vein. The marrow replaces the
marrow that was destroyed. A bone marrow transplant using marrow
from a relative or person not related to the patient is called an
allogeneic bone marrow transplant.
An even newer type of bone marrow transplant, called
bone marrow transplant
, is being studied in clinical trials.
During this procedure, bone marrow is taken from the patient and
may be treated with drugs to kill any cancer cells. The marrow is
frozen to save it. The patient is then given high-dose chemotherapy
with or without radiation therapy to destroy all of the remaining
marrow. The frozen marrow that was saved is thawed and given
through a needle in a vein to replace the marrow that was
There are generally four phases of treatment for ALL.
The first phase,
remission induction therapy
chemotherapy to kill as many of the leukemia cells as possible to
cause the cancer to go into remission.
The second phase, called
central nervous system (CNS)
, is preventive therapy. It involves using
intrathecal and/or high-dose systemic chemotherapy to the CNS to
kill any leukemia cells present there. It is also used to prevent
the spread of cancer cells to the brain and spinal cord even if no
cancer has been detected there. Radiation therapy to the brain may
also be given, in addition to chemotherapy, for this purpose. CNS
prophylaxis is often given in conjunction with
Once a child goes into remission and there are no signs of
leukemia, a third phase of treatment called
, is given. Consolidation therapy uses
high-dose chemotherapy to attempt to kill any remaining leukemia
The fourth phase of treatment, called
, uses chemotherapy for several years to maintain the
Treatment for childhood acute lymphoblastic leukemia depends on
the prognostic group to which your child is assigned. This is based
primarily on your child's age and white blood cell count at
diagnosis. Your child may receive treatment that is considered
standard based on its effectiveness in a number of patients in past
studies. Or you may choose to have your child take part in a
clinical trial. Not all patients are cured with standard therapy
and some standard treatments may have more side effects than are
desired. For these reasons, clinical trials are designed to test
new treatments and to find better ways to treat cancer patients.
Clinical trials are ongoing in most parts of the country for most
stages of childhood ALL. For more information, call the Cancer
Information Service at 1-800-4-CANCER (1-800-422-6237); TTY at
Untreated childhood acute lymphoblastic leukemia
Your child's treatment will probably be remission induction
chemotherapy to kill cancer cells and cause the leukemia to go into
remission. Induction chemotherapy is almost always successful in
inducing remission. Intrathecal and/or high-dose systemic
chemotherapy, with or without radiation therapy to the brain, may
also be given. This helps to prevent the spread of cancer cells to
the brain and spinal cord. Clinical trials are testing new ways of
Childhood acute lymphoblastic leukemia in remission
Your child's treatment will probably be intensive chemotherapy
to kill any remaining cancer cells. Intrathecal and/or high doses
of systemic chemotherapy, with or without radiation therapy to the
brain, may also be given during this phase of treatment. This is
given to prevent the spread of cancer cells to the brain and spinal
cord. Following intensification therapy, chemotherapy generally
continues until the child has been in continuous remission for
Recurrent childhood acute lymphoblastic leukemia
Treatment depends on the type of treatment your child received
before, how soon the cancer came back following treatment, and
whether the leukemia cells are found outside the bone marrow. Your
child's treatment will probably be systemic or intrathecal
chemotherapy, radiation therapy, or bone marrow transplantation.
You may want to consider entering your child into a clinical trial
of new chemotherapy drugs or bone marrow transplantation.