A stem cell transplant (SCT) can sometimes be used for children whose chances of being cured are poor with standard or even intense chemotherapy. SCT lets doctors use even higher doses of chemotherapy than a child could normally tolerate.
High-dose chemotherapy destroys the bone marrow, which is where new blood cells are formed. This could lead to life-threatening infections, bleeding, and other problems caused by low blood cell counts. A stem cell transplant is given after the chemo to restore the blood-forming stem cells in the bone marrow.
The blood-forming stem cells used for a transplant can come either from the blood or from the bone marrow. Sometimes stem cells from a baby’s umbilical cord blood are used.
Allogeneic stem cell transplant
For childhood leukemias, the type of transplant used is known as an allogeneic stem cell transplant. In this type of transplant, the blood-forming stem cells are donated from another person.
The donor’s tissue type (also known as the HLA type) should match the patient’s tissue type as closely as possible to help prevent the risk of major problems with the transplant. Tissue type is based on certain substances on the surface of cells in the body. The closer the tissue match between the donor and the recipient, the better the chance the transplanted cells will “take” and begin making new blood cells.
The donor is usually a brother or sister with the same tissue type as the patient. Rarely, it can be an HLA-matched, unrelated donor – a stranger who has volunteered to donate blood-forming stem cells. Sometimes umbilical cord stem cells are used. These stem cells come from blood drained from the umbilical cord and placenta after a baby is born and the umbilical cord is cut. (This blood is rich in stem cells.) Whatever their source, the stem cells are then frozen and stored until they are needed for the transplant.
To learn about how a stem cell transplant is done, see Stem Cell Transplant (Peripheral Blood, Bone Marrow, and Cord Blood Transplants).
When stem cell transplant (SCT) might be used
Acute lymphocytic leukemia (ALL): In ALL, SCT might be used for a child whose leukemia doesn’t respond well to initial treatment or relapses (comes back) early after going into remission. It’s less clear if SCT should be used for children whose ALL relapses more than 6 months after finishing the initial chemotherapy. These children will often do well with another round of standard dose chemotherapy.
SCT may also be recommended for children with some less common forms of ALL, such as those whose leukemias have the Philadelphia chromosome or those with T-cell ALL that doesn’t respond well to initial treatment.
Acute myelogenous leukemia (AML): Because AML relapses more often than ALL, many doctors recommend SCT for children with AML right after they have gone into remission, if the child has a brother or sister with the same tissue type who can donate stem cells for the transplant. This is especially true if there is a very high risk of relapse (as with some subtypes of AML or when there are certain chromosome changes in the cells). There is still some debate about which children with AML need this type of intensive treatment.
If a child with AML relapses after his or her first round of standard chemotherapy, most doctors will recommend SCT as soon as the child goes into remission again.
In either case, it is important that the leukemia is in remission before getting a stem cell transplant. Otherwise, the leukemia is more likely to return.
Other leukemias: SCT might also offer the best chance to cure some less common types of childhood leukemia, such as juvenile myelomonocytic leukemia (JMML) and chronic myelogenous leukemia (CML). For CML, newer targeted therapies are likely to be used first for most children, but a transplant might still be needed at some point.
A stem cell transplant is a complex treatment that can cause life-threatening side effects. If the doctors think your child can benefit from a transplant, the best place to have this done is at a nationally recognized cancer center where the staff has experience with the procedure and with managing the recovery period.
A stem cell transplant often requires a long hospital stay and can be very expensive (often costing well over $100,000). Be sure to get a written approval from your insurer before treatment if it is recommended for your child. Even if the transplant is covered by your insurance, your co-pays or other costs could easily amount to many thousands of dollars. It’s important to find out what your insurer will cover before the transplant to get an idea of what you might have to pay.
Possible side effects of stem cell transplant
The possible side effects from SCT are generally divided into short and long-term effects.
Short-term side effects
The early complications and side effects are basically those caused by high-dose chemotherapy (see the “Chemotherapy” section of this document), but they can be more severe. They can include:
- Low blood cell counts (with fatigue and an increased risk of infection and bleeding)
- Nausea and vomiting
- Loss of appetite
- Mouth sores
- Hair loss
One of the most common and serious short-term effects is the increased risk of serious infections. Antibiotics are often given to try to prevent this from happening. Other side effects, like low red blood cell and platelet counts, may require blood product transfusions or other treatments.
Long-term and late side effects
Some complications and side effects can last for a long time or might not occur until months or years after the transplant. These can include:
- Graft-versus-host disease (see below)
- Radiation damage to the lungs
- Problems with the thyroid or other hormone-making glands
- Problems with fertility
- Damage to bones or problems with bone growth
- Development of another cancer (including leukemia) years later
Graft-versus-host disease (GVHD) is one of the most serious complications of allogeneic stem cell transplants. This happens when the donor immune system cells attack the patient’s own cells. GVHD can be acute or chronic, based on how soon after the transplant it begins.
The parts of the body most often affected by GVHD include the skin, liver, and digestive tract. The most common symptoms are severe skin rashes and severe diarrhea. If the liver is affected, the damage can lead to jaundice (yellowing of the skin and eyes) or even liver failure. GVHD can also cause lung damage, leading to problems breathing. The patient may feel weak, become tired easily, and have nausea, dry mouth, and muscle aches.
In severe cases, GVHD can be life-threatening. Drugs that weaken the immune system are often given as a part of the transplant to try to prevent GVHD, although they can have their own side effects.
On the good side, GVHD can lead to graft-versus-leukemia activity, in which any remaining leukemia cells are killed by the donor immune cells.
Be sure to talk to your child’s doctor before the transplant to learn about possible long-term effects your child might have. More information on long-term effects can be found in the section “What happens after treatment for childhood leukemia?”
To learn more about stem cell transplants, see Stem Cell Transplant (Peripheral Blood, Bone Marrow, and Cord Blood Transplants).
Last Revised: 02/03/2016