Treatment Overview
What is a stem cell transplant?
Most stem cells are in your
bone marrow. You also have some that circulate from
your marrow into your blood. Bone marrow stem cells turn into
red blood cells,
white blood cells, or
platelets to help your body stay healthy. If your bone
marrow is damaged or destroyed, it can no longer make normal blood cells. In a
stem cell transplant, healthy stem cells are placed in your body through an
IV to help your bone marrow start to work right.
When the stem cells come from another person, it is called an
allogeneic transplant. The donor may be a relative or a complete stranger. The
important thing is that the donor's blood is closely matched to yours. This is
more likely when the donor is your brother or sister.
When the stem cells come from your own blood or bone marrow, it
is called an
autologous transplant.
Stem cells can also be found in your bloodstream and in the blood
inside a newborn's
umbilical cord.
When is a stem cell transplant needed?
Doctors use stem cell transplants to:
Other uses for stem cells are being studied, such as the
treatment of immune system defects,
diabetes,
sickle cell disease, and
thalassemia.
How do I know if I am a good candidate for a stem cell transplant?
Your doctor will consider your health and your age. People who
are good candidates usually are younger than 60, do not have other diseases
such as heart disease or diabetes, and have a normal kidney and liver. Your
doctor will also consider how much your disease has grown and how aggressive
your cancer is. People with aggressive cancer that has spread to many areas of
the body are not usually good candidates. Your doctor may also consider if you
have cancer that has come back, such as relapsed
non-Hodgkin's lymphoma or
leukemia.
How are stem cells collected?
It depends on where the stem cells come from. If they are taken
from the bone marrow, a small amount of the liquid portion of the bone marrow
is removed through a needle inserted into the bone. This is done many times to
collect enough stem cells for the person receiving the donated bone marrow.
This is called a
bone marrow aspiration. The bone marrow cells are put
into a blood bag. They are often frozen for future use.
If the stem cells are taken from blood, the growth factor G-CSF
may be used to stimulate the growth of new stem cells so they spill over into
the blood. G-CSF is a protein that is produced naturally in the body. G-CSF may
be used so a transplant can be done as soon as possible and a chemotherapy dose
does not have to be lowered to allow stem cells to grow. The blood is removed
from the vein in one arm and passed through a machine that takes out the stem
cells. The machine then returns the remaining blood through a needle in the
person's other arm. This is called
apheresis.
Why are chemotherapy and radiation therapy used before a transplant?
Doctors use chemotherapy and radiation to destroy your bone
marrow. This also gets rid of the cancer cells—along with the normal cells—in
your bone marrow. Later, when you get healthy cells from a donor, those new
cells will go to the marrow and be able to take over the job of making new
blood cells.
How are stem cells transplanted?
An
IV is inserted in your neck or chest. The stem cells
travel through the IV, into your blood, and to your bone marrow, where they
will begin to produce new cells in 1 to 3 weeks. During this time:
- You will be in isolation and given
antibiotics to prevent or treat infection. Because the chemotherapy destroys
your white blood cells, your body will not be able to fight infection until it
starts making new white blood cells.
- Your blood will be tested
often to check the levels of red blood cells, white blood cells, and platelets
in your body.
- You may need to receive several
transfusions of blood cells and platelets until your
body begins to produce its own.
- You may need more antibiotics or
other medicines if you get an infection.
What new techniques are being developed?
Researchers are studying a new technique called a mini-transplant
or nonmyeloablative transplant. This involves giving lower, less harmful doses
of chemotherapy and radiation than used in normal transplants. Lower doses
destroy some, but not all, of your bone marrow and weaken your immune system to
keep your body from rejecting the transplanted cells. Since lower doses of
chemotherapy and radiation therapy are used, the transplant is less dangerous.
This may be a good treatment option for people who would otherwise not be
considered for an allogeneic stem cell transplant.1
What To Expect After Treatment
If the donated stem cells came from bone marrow or umbilical cord
blood, it usually takes about 20 days for your bone marrow to start producing
new blood cells. If the donated cells came from someone's blood, it usually
takes less than 10 days.
You may spend 5 weeks or longer in the hospital after an allogeneic
stem cell transplant. About 1 out of 4 people need to be readmitted within the
first 3 months because of complications.
After you are discharged from the hospital, you will continue to
see your doctor often. Because you received someone else's bone marrow, you
will need treatment with medicines to prevent your
immune system from attacking the donor marrow as
though it were a foreign substance. You may also take medicine to help prevent
the donor cells from attacking your body. Most people who do not have an immune
system reaction take these medications for 2 to 6 months.
Serious complications can develop after a stem cell transplant.
They include:
- Graft-versus-host disease. The new cells may
destroy other cells in your body. They most commonly attack the skin, liver,
and digestive system. This happens less often when umbilical cord stem cells
are used. Stem cells from umbilical cord blood are usually used to treat
disease in a sibling or child who would otherwise not have a stem cell donor.
Since there are so few stem cells found in cord blood, these cells are not
usually used to treat adults.
- Graft rejection. Your body may not
accept the new stem cells.
- Severe life-threatening infection. When
your immune system has been weakened, even the most minor infection can be
dangerous.
- Veno-occlusive disease. This is a serious liver problem
caused by the high dose of chemotherapy or radiation given before a transplant.
Symptoms will usually appear within 3 weeks of your transplant and include
swelling and tenderness of the liver, weight gain,
jaundice, and fluid buildup in the belly.
When stem cells are collected from another person, the cells are
tested to make sure they match your cells.
Although a transplant from an unrelated donor is more likely to
cause problems, improvements in the way the cells are prepared and matched and
in the care of the person after the transplant have cut down on problems. But
it can take 4 months or longer to find a match from an unrelated donor.
Why It Is Done
Allogeneic transplants are used to treat:
Allogeneic transplants are also used experimentally for other
diseases, such as:
How Well It Works
The success of a stem cell transplant depends on your age and
general health, the type and stage of disease, and how well the donor matches.
Serious complications can develop after a stem cell transplant.
The original disease often comes back, or relapses, after an
allogeneic transplant. If relapse occurs, it can be treated with a second
transplant, chemotherapy, or other treatments.
Risks
Early complications usually occur within 5 to 10 days and include:
- Mouth sores.
- Hair
loss.
- Bleeding, because of severe reduction in red blood cells,
white blood cells, and platelets.
- Nausea and
vomiting.
- Diarrhea.
- Infection, such as
pneumonia,
shingles, or
herpes simplex.
Other possible complications include:
- Depression.
- Infertility.
- Cataracts.
- Kidney, lung, and heart
complications.
- Recurrence of the disease that the transplant was
used to treat.
- Other cancers.
Serious, long-term complications include:
- Graft failure. The new
stem cells do not work, or they work for a short time and then fail. Once this
occurs, the likelihood of a cure is low.
- Graft-versus-host disease (GVHD). The new stem cells attack
other cells in your body. If it happens within 3 months, it is called acute
GVHD. If it happens after 3 months, it is called chronic GVHD. Once chronic
GVHD develops, it may take as long as 3 years to go away. GVHD affects the
skin, gastrointestinal tract, and liver. It can cause death. GVHD is treated
with medicine that lowers the activity of your
immune system. GVHD does not occur when an identical
twin is the donor.
- Veno-occlusive disease.
This is a serious liver problem caused by the high dose of chemotherapy or
radiation given before a transplant. Symptoms include swelling and tenderness
of the liver, weight gain,
jaundice, and fluid buildup in the belly.
What To Think About
Who can donate stem cells?
Healthy adults between the ages of 18 and 60 can donate stem
cells. About 8 million people worldwide and about 4 million people in the
United States are registered to be stem cell donors. Children may be donors for
themselves or a brother or sister. In some cases, people who are older than 60
can donate.
If you wish to be a stem cell donor, a blood sample is taken from
you and tested for
tissue type. It is then compared with the tissue types
of people needing a transplant. If a match is found, another blood sample will
be drawn to see if your tissue type matches well enough for the
transplant.
If you are selected as a stem cell donor, you will have a
complete physical exam. You will also be asked questions about your health and
your family history of diseases. You will also be asked to sign a consent form
to have the procedure.
If you are a stem cell donor, you will receive injections of a
drug called filgrastim for several days. (It is also called G-CSF, for
"granulocyte colony-stimulating factor"). Filgrastim is a drug that helps your
body move more white blood cells out of your bone marrow and into your
bloodstream. Blood will be removed from your arm, sent through a machine to
remove the stem cells, and returned to your bloodstream through your other
arm.
The bone marrow collection process is a surgical procedure done
under a
local or
general anesthetic. The procedure takes 1 to 2 hours.
Bone marrow is usually removed from the back of your pelvic bone using sterile
needles.
What about umbilical cord blood banking?
Umbilical cord blood banks have been established in some areas of
the United States, Canada, and many countries in Europe to supply stem cells
for related and unrelated people. Using blood from these banks decreases the
time it takes to search for a match, because the samples are already typed for
genetic information (HLA) and blood group and treated for infection. The match
does not need to be as specific as it does with bone marrow or peripheral stem
cells. Umbilical cord blood transplants also cause fewer problems with
graft-versus-host disease.
Specialized hospitals
Not every hospital is able to perform transplants. You may have
to travel to a hospital that has special equipment and specially trained
doctors and nurses. Transplants are very expensive and are not always covered
by insurance.
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