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.
