The goal of stem cell transplantation is to cure the patient’s cancer by destroying the cancer cells in the bone marrow with high doses of chemotherapy and then replacing them with new, healthy blood-forming stem cells. The healthy blood stem cells will grow and multiply forming new bone marrow and blood cells. There are two main types of stem cell transplantation. They are
- Allogeneic—patients receive stem cells from a matched or a partially mismatched related donor or an unrelated donor.
- Autologous—patients receive their own stem cells.
Stem cell transplantation is not used as the first or primary treatment for ALL. It may be used as a treatment for high-risk ALL patients or for patients who do not respond to treatment. Stem cell transplantation is a complex treatment. It can cause serious side effects that can be life threatening so it may not be a treatment option for every ALL patient. Talk to your doctor about whether stem cell transplantation is a treatment option for you.
Allogeneic Stem Cell Transplantation
Allogeneic stem cell transplantation involves transferring stem cells from a healthy person (the donor) to the patient.
The goals of an allogeneic transplant are to:
- Restore the body’s ability to make normal blood cells after high-dose chemotherapy
- Cure the patient of his or her ALL by killing any remaining ALL cells.
To prepare for the transplant, the patient receives high-intensity chemotherapy, either with or without radition, to kill the reamining leukemic cells in the body. Unfortunately, this also destroy normal stem cells in the bone marrow. Then, the patient received infusions of the donor stem cells. The donated stem cells restore the bone marrow's ability to form new blood cells.
Donor stem cells come from an HLA-matched or partially mismatched
- Family member
- Unrelated donor
- Umbilical cord blood unit.
An allogeneic transplant is a high-risk procedure. Doctors are working to make allogeneic transplants safer. An allogeneic transplant may be a choice for an adult ALL patient if
- He or she is not responding well to other treatments
- The expected benefits of an allogeneic transplant exceed the risks
- There is a stem cell donor.
The upper age limit for an allogeneic transplant depends on the treatment center.
A stem cell transplant is usually not considered for a child unless
- Doctors have determined that the child’s type of ALL is not likely to respond well to chemotherapy
- Chemotherapy has not worked well
- The ALL has returned (relapsed).
Reduced-Intensity Allogeneic Stem Cell Transplantation
A reduced-intensity allogeneic transplant uses lower doses of chemotherapy than a standard allogeneic transplant; it does not completely inactivate the patient’s immune system or treat the ALL as aggressively. Some older and sicker patients may be helped by this treatment.
A serious risk of allogeneic and reduced-intensity allogenic stem cell transplantation is graft versus host disease (GVHD), which develops if the donor's immune cells attack your normal tissue. GVHD's effects can range from minor to life threatening.
Autologous Stem Cell Transplantation
An autologous transplant uses the patient’s own stem cells. Your doctor will talk with you about whether an autologous transplant is a treatment option for you. It is not commonly used to treat ALL. This is because of the high relapse rate following this type of transplant.