What Is Leukemia?
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.
Picture of blood cells maturing from stem
cells.
The bone marrow makes different types of
blood cells. Each type has a special
function:
White blood cells help fight infection.
Red blood cells carry oxygen to tissues
throughout the body.
Platelets help form blood clots that
control bleeding.
Leukemia Cells
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
quickly):
• 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 blood rises.
• 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 leukemia.
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
children.
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 a disease.
Studies have found the following risk
factors for leukemia:
• 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 to leukemia.
• 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 for
checkups.
Symptoms
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
• Headache
• 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 worse gradually.
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.
Diagnosis
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, and
liver.
• 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:
o Bone marrow aspiration: The doctor uses
a needle to remove samples of bone
marrow.
o 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 of
problems.
• 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 bone?
• 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?
Treatment
Many people with leukemia want to take an
active part in making decisions about
their medical care. They want to learn all
they can about their disease and their
treatment choices. However, the shock and
stress after a diagnosis of cancer can
make it hard to think of everything to ask
the doctor. Often it helps to make a list
of questions before an appointment. To
help remember what the doctor says,
patients may take notes or ask whether
they may use a tape recorder. Some also
want to have a family member or friend
with them when they talk to the doctor—to
take part in the discussion, to take
notes, or just to listen.
The doctor may refer patients to doctors
who specialize in treating leukemia, or
patients may ask for a referral.
Specialists who treat leukemia include
hematologists, medical oncologists, and
radiation oncologists. Pediatric
oncologists and hematologists treat
childhood leukemia.
Whenever possible, patients should be
treated at a medical center that has
doctors experienced in treating leukemia.
If this is not possible, the patient’s
doctor may discuss the treatment plan with
a specialist at such a center.
Getting a Second Opinion
Sometimes it is helpful to have a second
opinion about the diagnosis and the
treatment plan. Some insurance companies
require a second opinion; others may cover
a second opinion if the patient or doctor
requests it. There are a number of ways to
find a doctor for a second opinion:
• The patient’s doctor may be able to
suggest a doctor who specializes in adult
or childhood leukemia. At cancer centers,
several specialists often work together as
a team.
• The Cancer Information Service, at
1-800-4-CANCER, can tell callers about
nearby treatment centers.
A local or state medical society, a nearby
hospital, or a medical school can usually
provide the names of specialists.
• The Official ABMS Directory of Board
Certified Medical Specialists lists
doctors' names along with their specialty
and their educational background.
Board-certified doctors have met specific
education and training requirements and
have passed an examination given by a
specialty board. The directory is
available in most public libraries. The
American Board of Medical Specialties
(ABMS) also offers information about board
certification by telephone and on the
Internet. The toll-free telephone number
is 1-866-ASK-ABMS (1-866-275-2267). The
Internet address is h
ttp://www.abms.org.
Preparing for Treatment
The doctor can describe treatment choices
and discuss the results expected with each
treatment option. The doctor and patient
can work together to develop a treatment
plan that fits the patient’s needs.
Treatment depends on a number of factors,
including the type of leukemia, the
patient’s age, whether leukemia cells are
present in the cerebrospinal fluid, and
whether the leukemia has been treated
before. It also may depend on certain
features of the leukemia cells. The doctor
also takes into consideration the
patient’s symptoms and general health.
These are some questions a person may want
to ask the doctor before treatment
begins:
• What type of leukemia do I have?
• What are my treatment choices? Which do
you recommend for me? Why?
• What are the benefits of each kind of
treatment?
• What are the risks and possible side
effects of each treatment?
• If I have pain, how will you help me?
• What is the treatment likely to cost?
• How will treatment affect my normal
activities?
• Would a clinical trial (research study)
be appropriate for me? Can you help me
find one?
People do not need to ask all of their
questions or understand all of the answers
at one time. They will have other chances
to ask the doctor to explain things that
are not clear and to ask for more
information.
Methods of Treatment
The doctor is the best person to describe
the treatment choices and discuss the
expected results. Depending on the type
and extent of the disease, patients may
have chemotherapy, biological therapy,
radiation therapy, or bone marrow
transplantation. If the patient’s spleen
is enlarged, the doctor may suggest
surgery to remove it. Some patients
receive a combination of treatments.
People with acute leukemia need to be
treated right away. The goal of treatment
is to bring about a remission. Then, when
signs and symptoms disappear, more therapy
may be given to prevent a relapse. This
type of therapy is called maintenance
therapy. Many people with acute leukemia
can be cured.
Chronic leukemia patients who do not have
symptoms may not require immediate
treatment. The doctor may suggest watchful
waiting for some patients with chronic
lymphocytic leukemia. The health care team
will monitor the patient’s health so that
treatment can begin if symptoms occur or
worsen. When treatment for chronic
leukemia is needed, it can often control
the disease and its symptoms. However,
chronic leukemia can seldom be cured.
Patients may receive maintenance therapy
to help keep the cancer in remission.
A patient may want to talk to the doctor
about taking part in a clinical trial, a
research study of new treatment methods.
The section on “The Promise of Cancer
Research” has more information about
clinical trials.
In addition to anticancer therapy, people
with leukemia may have treatment to
control pain and other symptoms of the
cancer, to relieve the side effects of
therapy, or to ease emotional problems.
This kind of treatment is called symptom
management, supportive care, or palliative
care.
Chemotherapy
Most patients with leukemia receive
chemotherapy. This type of cancer
treatment uses drugs to kill leukemia
cells. Depending on the type of leukemia,
the patient may receive a single drug or a
combination of two or more drugs.
People with leukemia may receive
chemotherapy in several different ways:
• By mouth
• By injection directly into a vein (IV or
intravenous)
• Through a catheter (a thin, flexible
tube) placed in a large vein, often in the
upper chest—A catheter that stays in place
is useful for patients who need many IV
treatments. The health care professional
injects drugs into the catheter, rather
than directly into a vein. This method
avoids the need for many injections, which
can cause discomfort and injure the veins
and skin.
• By injection directly into the
cerebrospinal fluid—If the pathologist
finds leukemia cells in the fluid that
fills the spaces in and around the brain
and spinal cord, the doctor may order
intrathecal chemotherapy. The doctor
injects drugs directly into the
cerebrospinal fluid. This method is used
because drugs given by IV injection or
taken by mouth often do not reach cells in
the brain and spinal cord. (A network of
blood vessels filters blood going to the
brain and spinal cord. This blood-brain
barrier stops drugs from reaching the
brain.)
The patient may receive the drugs in two
ways:
o Injection into the spine: The doctor
injects the drugs into the lower part of
the spinal column.
o Ommaya reservoir: Children and some
adult patients receive intrathecal
chemotherapy through a special catheter
called an Ommaya reservoir. The doctor
places the catheter under the scalp. The
doctor injects the anticancer drugs into
the catheter. This method avoids the
discomfort of injections into the spine.
Patients receive chemotherapy in cycles: a
treatment period, then a recovery period,
and then another treatment period. In some
cases, the patient has chemotherapy as an
outpatient at the hospital, at the
doctor’s office, or at home. However,
depending on which drugs are given, and
the patient’s general health, a hospital
stay may be necessary.
Some people with chronic myeloid leukemia
receive a new type of treatment called
targeted therapy. Targeted therapy blocks
the production of leukemia cells but does
not harm normal cells. Gleevec, also
called STI-571, is the first targeted
therapy approved for chronic myeloid
leukemia.
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Biological Therapy
People with some types of leukemia have
biological therapy. This type of treatment
improves the body’s natural defenses
against cancer. The therapy is given by
injection into a vein.
For some patients with chronic lymphocytic
leukemia, the type of biological therapy
used is a monoclonal antibody. This
substance binds to the leukemia cells.
This therapy enables the immune system to
kill leukemia cells in the blood and bone
marrow.
For some patients with chronic myeloid
leukemia, the biological therapy is a
natural substance called interferon. This
substance can slow the growth of leukemia
cells.
Patients may want to ask these questions
about chemotherapy or biological therapy:
• Why do I need this treatment?
• What drugs will I get?
• Should I see my dentist before treatment
begins?
• What will the treatment do?
• Will I have to stay in the hospital?
• How will we know the drugs are working?
• How long will I be on this treatment?
• Will I have side effects during
treatment? How long will they last? What
can I do about them?
• Can these drugs cause side effects later
on?
• How often will I need checkups?
Radiation Therapy
Radiation therapy (also called
radiotherapy) uses high-energy rays to
kill leukemia cells. For most patients, a
large machine directs radiation at the
spleen, the brain, or other parts of the
body where leukemia cells have collected.
Some patients receive radiation that is
directed to the whole body. (Total-body
irradiation usually is given before a bone
marrow transplant.) Patients receive
radiation therapy at a hospital or
clinic.
These are some questions a person may want
to ask the doctor before having radiation
therapy:
• Why do I need this treatment?
• When will the treatments begin? How
often will they be given? When will they
end?
• How will I feel during therapy? Will
there be side effects? How long will they
last? What can we do about them?
• Can radiation therapy cause side effects
later on?
• What can I do to take care of myself
during therapy?
• How will we know if the radiation is
working?
• Will I be able to continue my normal
activities during treatment?
• How often will I need checkups?
Stem Cell Transplantation
Some patients with leukemia have stem cell
transplantation. A stem cell transplant
allows a patient to be treated with high
doses of drugs, radiation, or both. The
high doses destroy both leukemia cells and
normal blood cells in the bone marrow.
Later, the patient receives healthy stem
cells through a flexible tube that is
placed in a large vein in the neck or
chest area. New blood cells develop from
the transplanted stem cells.
There are several types of stem cell
transplantation:
• Bone marrow transplantation—The stem
cells come from bone marrow.
• Peripheral stem cell transplantation—The
stem cells come from peripheral blood.
• Umbilical cord blood transplantation—For
a child with no donor, the doctor may use
stem cells from umbilical cord blood. The
umbilical cord blood is from a newborn
baby. Sometimes umbilical cord blood is
frozen for use later.
Stem cells may come from the patient or
from a donor:
• Autologous stem cell
transplantation—This type of transplant
uses the patient’s own stem cells. The
stem cells are removed from the patient,
and the cells may be treated to kill any
leukemia cells present. The stem cells are
frozen and stored. After the patient
receives high-dose chemotherapy or
radiation therapy, the stored stem cells
are thawed and returned to the patient.
• Allogeneic stem cell
transplantation—This type of transplant
uses healthy stem cells from a donor. The
patient's brother, sister, or parent may
be the donor. Sometimes the stem cells
come from an unrelated donor. Doctors use
blood tests to be sure the donor’s cells
match the patient’s cells.
• Syngeneic stem cell transplantation—This
type of transplant uses stem cells from
the patient’s healthy identical twin.
After a stem cell transplant, patients
usually stay in the hospital for several
weeks. The health care team protects
patients from infection until the
transplanted stem cells begin to produce
enough white blood cells.
These are some questions a person may want
to ask the doctor before having a stem
cell transplant:
• What kind of stem cell transplant will I
have? If I need a donor, how will we find
one?
• How long will I be in the hospital? What
care will I need when I leave the
hospital?
• How will we know if the treatment is
working?
• What are the risks and the side effects?
What can we do about them?
• What changes in normal activities will
be necessary?
• What is my chance of a full recovery?
How long will that take?
• How often will I need checkups?
Side Effects of Cancer Treatment
Because cancer treatment may damage
healthy cells and tissues, unwanted side
effects are common. Specific side effects
depend on many factors, including the type
and extent of the treatment. Side effects
may not be the same for each person, and
they may even change from one treatment
session to the next. Before treatment
starts, health care providers will explain
possible side effects and suggest ways to
manage them.
The NCI provides helpful booklets about
cancer treatments and coping with side
effects, such as Chemotherapy and You,
Radiation Therapy and You, and Eating
Hints for Cancer Patients. See the
“National Cancer Institute Information
Resources” section for other sources of
information about side effects. NCI’s Web
site includes a section called “Coping
with Cancer” at http://cancer.gov/cancer_i
nformation. This section presents
information about coping with fatigue,
pain, and other problems.
Chemotherapy
The side effects of chemotherapy depend
mainly on the specific drugs and the dose.
In general, anticancer drugs affect cells
that divide rapidly, especially leukemia
cells. Chemotherapy can also affect other
rapidly dividing cells:
• Blood cells: These cells fight
infection, help the blood to clot, and
carry oxygen to all parts of the body.
When blood cells are affected, patients
are more likely to get infections, may
bruise or bleed easily, and may feel very
weak and tired.
• Cells in hair roots: Chemotherapy can
lead to hair loss. The hair grows back,
but the new hair may be somewhat different
in color and texture.
• Cells that line the digestive tract:
Chemotherapy can cause mouth and lip
sores, nausea and vomiting, diarrhea, and
poor appetite. Many of these side effects
can be controlled with drugs.
Some anticancer drugs can affect a
patient’s fertility. Women may have
irregular menstrual periods or periods may
stop altogether. Women may have symptoms
of menopause, such as hot flashes and
vaginal dryness. Men may stop producing
sperm. Because these changes may be
permanent, some men have their sperm
frozen and stored before treatment. Most
children treated for leukemia appear to
have normal fertility when they grow up.
However, depending on the drugs and doses
used and the age of the patient, some boys
and girls may be infertile when they
mature.
Because targeted therapy (sometimes used
for chronic myeloid leukemia) affects only
leukemia cells, it causes fewer side
effects than most other anticancer drugs.
However, Gleevec may cause patients to
retain water. This may cause swelling or
bloating.
Biological Therapy
The side effects of biological therapy
differ with the types of substances used,
and from patient to patient. Rashes or
swelling where the biological therapy is
injected are common. Flu-like symptoms
also may occur. The health care team may
monitor the blood for signs of anemia and
other problems.
Radiation Therapy
Radiation therapy may cause patients to
become very tired as treatment continues.
Resting is important, but doctors usually
advise patients to try to stay as active
as they can. In addition, when patients
receive radiation therapy, it is common
for their skin to become red, dry, and
tender in the treated area. Other side
effects depend on the area of the body
that is treated. If chemotherapy is given
at the same time, the side effects may be
worse. The doctor can suggest ways to ease
these problems.
Stem Cell Transplantation
Patients who have stem cell
transplantation face an increased risk of
infection, bleeding, and other side
effects because of the large doses of
chemotherapy and radiation they receive.
In addition, graft-versus-host disease
(GVHD) may occur in patients who receive
stem cells from a donor’s bone marrow. In
GVHD, the donated stem cells react against
the patient’s tissues. Most often, the
liver, skin, or digestive tract is
affected. GVHD can be mild or very severe.
It can occur any time after the
transplant, even years later. Steroids or
other drugs may help.
The NCI offers a fact sheet called
“Questions and Answers About Bone Marrow
Transplantation and Peripheral Blood Stem
Cell Transplantation.” It is available on
the Internet at http://cancer.gov/publications.<
/a> Also, information specialists at the
NCI's Cancer Information Service at
1-800-4-CANCER can send this fact sheet
and answer questions about stem cell
transplantation.
