What is adult acute lymphoblastic leukemia?
Adult acute lymphoblastic leukemia (also called acute lymphocytic leukemia or
ALL) is a disease in which too many infection-fighting white blood cells called
lymphocytes are found in the blood and bone marrow. Lymphocytes are made by
the bone marrow and by other organs of the lymph system. The bone marrow 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), and platelets (which make the
blood clot). Normally, the bone marrow makes cells called blasts that develop
(mature) into several different types of blood cells that have specific jobs to
do in the body.
Lymphocytes are found in the lymph which is a colorless, watery fluid present
in the lymph vessels. The lymph vessels are part of the lymph system which is
made up of thin tubes that branch, like blood vessels, into all parts of the
body. Along the network of vessels are groups of small, bean-shaped organs
called lymph nodes. Clusters of lymph nodes are found in the underarm, pelvis,
neck, and abdomen. The spleen (an organ in the upper abdomen that makes
lymphocytes and filters old blood cells from the blood), the thymus (a small
organ beneath the breastbone), and the tonsils (an organ in the throat) are
also part of the lymph system.
Lymphocytes fight infection by making substances called antibodies, which
attack germs and other harmful bacteria in the body. In ALL, the developing
lymphocytes do not mature and become too numerous. 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 the bone marrow cannot make enough red blood
cells to carry oxygen, then anemia may develop. If the bone marrow cannot make
enough platelets to make the blood clot normally, the bleeding or bruising may
develop more easily. The cancerous lymphocytes can also invade other organs,
the spinal cord, and the brain.
Leukemia can be acute (progressing quickly with many immature cancer cells) or
chronic (progressing slowly with more mature looking leukemia cells). ALL
progresses quickly and can occur in adults and children. Treatment is
different for adults than it is for children. (For more information on
childhood ALL, refer to the PDQ patient information summary on Childhood
Acute Lymphoblastic Leukemia. Separate PDQ patient information summaries are
also available on Chronic Lymphocytic Leukemia, Chronic Myelogenous
Leukemia, Adult or Childhood Acute Myeloid Leukemia, and Hairy Cell Leukemia Treatment.)
ALL is often difficult to diagnose. The early signs may be similar to the flu
or other common diseases. A doctor should be seen if the following signs or
symptoms won't go away: fever, persistant weakness or tiredness, achiness in
the bones or joints, or swollen lymph nodes.
If there are symptoms, a doctor may order blood tests to count the number of
each of the different kinds of blood cells. If the results of the blood tests
are not normal, a doctor may do a bone marrow biopsy. During this test, a
needle is inserted into a bone and a small amount of bone marrow is taken out
and looked at under the microscope. A doctor may also do a spinal tap in which
a needle is inserted through the back to take a sample of the fluid that
surrounds the brain and spine. The fluid is then looked at under a microscope
to see if leukemia cells are present. A doctor can then tell what kind of
leukemia is present and plan the best treatment.
The chance of recovery (prognosis) depends on how the leukemia cells look under
a microscope, how far the leukemia has spread, and the patient's age and
general health.