Source: Cancer Resource Room
Leukemia is a type of cancer. Cancer is
a group of many related diseases. All
cancers begin in cells, which make up
blood and other tissues. Normally, cells
grow and divide to form new cells as the
body needs them. When cells grow old,
they die, and new cells take their place.
Sometimes this orderly process goes wrong.
New cells form when the body does not
need them, and old cells do not die when
they should. Leukemia is cancer that begins
in blood cells.
Normal Blood Cells
Blood cells form in the bone
marrow. Bone marrow is the soft material
in the center of most bones.
Immature blood cells are called stem cells
and blasts. Most blood cells mature in
the bone marrow and then move into the
blood vessels. Blood flowing through the
blood vessels and heart is called the
peripheral blood. To see an example of
what the Blood
Cells look like >>>
In people with leukemia, the
bone marrow produces abnormal white blood
cells. The abnormal cells are leukemia
cells. At first, leukemia cells function
almost normally. In time, they may crowd
out normal white blood cells, red blood
cells, and platelets. This makes it hard
for blood to do its work.
Types of Leukemia
The types of leukemia are grouped
by how quickly the disease develops and
gets worse. Leukemia is either chronic
(gets worse slowly) or acute (gets worse
- Chronic leukemia—Early in the
disease, the abnormal blood cells
can still do their work, and people
with chronic leukemia may not have
any symptoms. Slowly, chronic leukemia
gets worse. It causes symptoms as
the number of leukemia cells in the
- Acute leukemia—The blood cells
are very abnormal. They cannot carry
out their normal work. The number
of abnormal cells increases rapidly.
Acute leukemia worsens quickly.
The types of leukemia are also grouped
by the type of white blood cell that is
affected. Leukemia can arise in lymphoid
cells or myeloid cells. Leukemia that
affects lymphoid cells is called lymphocytic
leukemia. Leukemia that affects myeloid
cells is called myeloid leukemia or myelogenous
There are four common types of leukemia:
- Chronic lymphocytic leukemia (chronic
lymphoblastic leukemia, CLL) accounts
for about 7,000 new cases of leukemia
each year. Most often, people diagnosed
with the disease are over age 55.
It almost never affects children.
- Chronic myeloid leukemia (chronic
myelogenous leukemia, CML) accounts
for about 4,400 new cases of leukemia
each year. It affects mainly adults.
- Acute lymphocytic leukemia (acute
lymphoblastic leukemia, ALL) accounts
for about 3,800 new cases of leukemia
each year. It is the most common type
of leukemia in young children. It
also affects adults.
- Acute myeloid leukemia (acute myelogenous
leukemia, AML) accounts for about
10,600 new cases of leukemia each
year. It occurs in both adults and
Hairy cell leukemia is a rare type of chronic
leukemia. This booklet does not deal with
hairy cell leukemia or other rare types
of leukemia. Together, these rare leukemias
account for about 5,200 new cases of leukemia
each year. The Cancer Information Service
(1-800-4-CANCER) can provide information
about these types of leukemia.
Leukemia: Who’s at Risk?
No one knows the exact causes
of leukemia. Doctors can seldom explain
why one person gets this disease and another
does not. However, research has shown
that people with certain risk factors
are more likely than others to develop
leukemia. A risk factor is anything that
increases a person’s chance of developing
Studies have found the following risk factors
- Very high levels of radiation—People
exposed to very high levels of radiation
are much more likely than others to
develop leukemia. Very high levels
of radiation have been caused by atomic
bomb explosions (such as those in
Japan during World War II) and nuclear
power plant accidents (such as the
Chernobyl [also called Chornobyl]
accident in 1986).
Medical treatment that uses radiation
can be another source of high-level
exposure. Radiation used for diagnosis,
however, exposes people to much lower
levels of radiation and is not linked
- Working with certain chemicals—Exposure
to high levels of benzene in the workplace
can cause leukemia. Benzene is used
widely in the chemical industry. Formaldehyde
is also used by the chemical industry.
Workers exposed to formaldehyde also
may be at greater risk of leukemia.
- Chemotherapy—Cancer patients
treated with certain cancer-fighting
drugs sometimes later develop leukemia.
For example, drugs known as alkylating
agents are associated with the development
of leukemia many years later.
- Down syndrome and certain other genetic
diseases—Some diseases caused
by abnormal chromosomes may increase
the risk of leukemia.
- Human T-cell leukemia virus-I (HTLV-I)—This
virus causes a rare type of chronic
lymphocytic leukemia known as human
T-cell leukemia. However, leukemia
does not appear to be contagious.
- Myelodysplastic syndrome—People
with this blood disease are at increased
risk of developing acute myeloid leukemia.
In the past, some studies suggested exposure
to electromagnetic fields as another possible
risk factor for leukemia. Electromagnetic
fields are a type of low-energy radiation
that comes from power lines and electric
appliances. However, results from recent
studies show that the evidence is weak
for electromagnetic fields as a risk factor.
Most people who have known risk factors
do not get leukemia. On the other hand,
many who do get the disease have none
of these risk factors. People who think
they may be at risk of leukemia should
discuss this concern with their doctor.
The doctor may suggest ways to reduce
the risk and can plan an appropriate schedule
Like all blood cells, leukemia cells travel
through the body. Depending on the number
of abnormal cells and where these cells
collect, patients with leukemia may have
a number of symptoms. Common symptoms
of leukemia may include:
- Fevers or night sweats
- Frequent infections
- Feeling weak or tired
- Bleeding and bruising easily (bleeding
gums, purplish patches in the skin,
or tiny red spots under the skin)
- Pain in the bones or joints
- Swelling or discomfort in the abdomen
(from an enlarged spleen)
- Swollen lymph nodes, especially in
the neck or armpit
- Weight loss
Such symptoms are not sure signs of leukemia.
An infection or another problem also could
cause these symptoms. Anyone with these
symptoms should see a doctor as soon as
possible. Only a doctor can diagnose and
treat the problem.
In the early stages of chronic leukemia,
the leukemia cells function almost normally.
Symptoms may not appear for a long time.
Doctors often find chronic leukemia during
a routine checkup—before there are
any symptoms. When symptoms do appear,
they generally are mild at first and get
In acute leukemia, symptoms appear and
get worse quickly. People with this disease
go to their doctor because they feel sick.
Other symptoms of acute leukemia are vomiting,
confusion, loss of muscle control, and
seizures. Leukemia cells also can collect
in the testicles and cause swelling. Also,
some patients develop sores in the eyes
or on the skin. Leukemia also can affect
the digestive tract, kidneys, lungs, or
other parts of the body.
If a person has symptoms that
suggest leukemia, the doctor may do a
physical exam and ask about the patient's
personal and family medical history. The
doctor also may order laboratory tests,
especially blood tests. The exams and
tests may include the following:
- Physical exam—The doctor checks
for swelling of the lymph nodes, spleen,
- Blood tests—The lab checks the
level of blood cells. Leukemia causes
a very high level of white blood cells.
It also causes low levels of platelets
and hemoglobin, which is found inside
red blood cells. The lab also may
check the blood for signs that leukemia
has affected the liver and kidneys.
- Biopsy—The doctor removes some
bone marrow from the hipbone or another
large bone. A pathologist examines
the sample under a microscope. The
removal of tissue to look for cancer
cells is called a biopsy. A biopsy
is the only sure way to know whether
leukemia cells are in the bone marrow.
There are two ways the doctor can
obtain bone marrow. Some patients
will have both procedures:
- Bone marrow aspiration: The
doctor uses a needle to remove
samples of bone marrow.
- Bone marrow biopsy: The doctor
uses a very thick needle to
remove a small piece of bone
and bone marrow.
( Local anesthesia helps to
make the patient more comfortable.)
- Cytogenetics—The lab looks at
the chromosomes of cells from samples
of peripheral blood, bone marrow,
or lymph nodes.
- Spinal tap—The doctor removes
some of the cerebrospinal fluid (the
fluid that fills the spaces in and
around the brain and spinal cord).
The doctor uses a long, thin needle
to remove fluid from the spinal column.
The procedure takes about 30 minutes
and is performed with local anesthesia.
The patient must lie flat for several
hours afterward to keep from getting
a headache. The lab checks the fluid
for leukemia cells or other signs
- Chest x-ray—The x-ray can reveal
signs of disease in the chest.
A person who needs a bone marrow aspiration
or bone marrow biopsy may want to ask
the doctor the following questions:
- Will you remove the sample of bone
marrow from the hip or from another
- How long will the procedure take?
Will I be awake? Will it hurt?
- How soon will you have the results?
Who will explain them to me?
- If I do have leukemia, who will talk
to me about treatment? When?
To read more about Leukemia
& Education Programs
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