Ewing Sarcoma: High-Dose Chemotherapy and Stem Cell Transplant
What is a stem cell transplant?
A stem cell transplant used very high doses of chemotherapy (chemo) to try to kill cancer cells all over the body. This high-dose chemo also destroys the bone marrow. This is the soft, spongy tissue inside the bones where new blood cells are made. Bone marrow (hematopoietic) stem cells are immature cells that are the starter cells for all types of blood cells. After the high-dose chemo, stem cells are "transplanted" or put into the body to replace the bone marrow that’s been destroyed by the chemo.
The healthy stem cells that are put in the body will grow and become new, healthy bone marrow cells. This bone marrow can then make new blood cells. A stem cell transplant lets healthcare providers use much higher doses of chemo than a person would normally be able to tolerate.
When might a stem cell transplant be used for Ewing sarcoma?
High dose chemo followed by a stem cell transplant might be used to treat Ewing sarcomas when:
The sarcoma has spread to other parts of the body
It's no longer responding to other treatments
The cancer has come back after treatment
Experts are working to find out how helpful stem cell transplants are for Ewing sarcoma. Stem cell transplants aren’t a main treatment for Ewing sarcoma. If a stem cell transplant is used, it’s often as part of a clinical trial.
Types of stem cell transplants
There are 2 kinds of stem cell transplants::
Autologous transplant. This means the stem cells are collected from your child's own body and preserved. This is done before he or she gets chemo.
Allogeneic transplant. This means the stem cells come from another person. This may be a brother or sister. Or it may also be from someone not related to your child.
For Ewing sarcoma, autologous transplants are used.
How stem cells are collected
From the blood
This is the most common source of stem cells for a transplant. Your child may get an injection of a growth factor medicine for several days. This medicine helps stimulate stem cells to be made. The process for collecting stem cells from the blood is called apheresis. It’s a lot like giving blood, but it takes longer. A thin, flexible tube (catheter) is used to get blood from your child's vein. The blood goes to a cell separation device to remove the stem cells. The stem cells are then frozen until they’re needed later. Then the extra blood is returned to your child. This process may need to be done more than once to collect the right amount of cells.
From the bone marrow
Stem cells may also be taken from the bone marrow. This process is done while your child is asleep with general anesthesia. A healthcare provider makes several punctures in the pelvic or hip bone to remove marrow. Soreness in the hip bone may last for several days. These stem cells are filtered and frozen until they’re needed. This approach to collecting stem cells is used less often than in the past.
Having the transplant
Your child will likely be admitted to the hospital the day before the transplant. The healthcare provider will go over ways to help your child stay away from germs. This is needed to lower your child's risk for infections.
After chemo or radiation is done, your child will get the stored stem cells through a needle in his or her arm that’s attached to a tube. This is like a blood transfusion.
You then have to wait for your child's new stem cells to start multiplying. The child may have to stay in isolation away from people to prevent getting an infection. Once part of the white blood cell count (absolute neutrophil count or ANC) reaches a safe level, your child can come out of isolation and then eventually go home. This may happen within several weeks. Or it may take longer.
Your child will need to have their blood drawn often to check their blood cell counts for the next several weeks. This can be done as outpatient.
Possible short-term side effects
Most of the short-term side effects of a stem cell transplant are from the high doses of chemo or radiation. These should go away as your child recovers from the transplant. Common side effects can include:
Low blood cell counts
Low blood pressure
Shortness of breath
Chest pain or tightness
Fever or chills
Loss of appetite
Possible long-term side effects
Some side effects of a stem cell transplant may be long-lasting or show up years later. These can include:
Bone pain. This is caused from damage because of too little blood (aseptic necrosis).
Growth of another cancer
Damage to other organs. These can include the heart, kidneys, or liver.
Lack of menstrual periods. This may mean ovary damage. It can cause infertility.
Vision problems. This can be caused by damage to the lens of the eye.
Weight gain. This may be a sign of thyroid gland damage.
Talking with your child's healthcare provider
Before your child has a stem cell transplant, it's important to discuss this procedure with your child's healthcare provider to make sure you understand the possible risks and benefits. A stem cell transplant is a complex procedure. It’s only done by healthcare provider with special training. If you decide this is the best option for your child, it's important to have it done at a hospital that specializes in stem cell transplants, such as a major cancer center. The procedure is also expensive. Check with your insurance provider to see how much of it will be covered.