What Happens During a Stem Cell Transplant for CML
Stem cell transplants may be autologous, which means the stem cells come from your own body. Or they may be allogeneic, which means the stem cells come from a donor. Donor (allogenic) transplants are the only known cure for CML and doctors prefer to use a donor (allogeneic) transplant for these two reasons:
Your own leukemia cells may not be completely separated out from your stem cells. So if you use your own stem cells, it is possible some leukemia cells will be given back to you after treatment.
Donor cells cause an immune reaction, which may be helpful in fighting the leukemia. Using your own stem cells would not cause such an immune reaction.
Discuss the risks and benefits with your doctor beforehand.
Here’s a general description of how a stem cell transplant is done.
Retrieving the needed stem cells
Stem cells may be collected in one of two ways:
For a bone marrow transplant, your doctor removes stem cells from either your bone marrow or that of your donor. You or the donor receives general anesthesia to fall asleep. A doctor makes several punctures in the pelvic bone to remove marrow. Soreness may last for several days. These stem cells are filtered and frozen until needed later. This type of transplant is used less often than in the past.
For a peripheral blood stem cell transplant, you or the donor gets a procedure called apheresis. This involves receiving a growth factor drug by injection for several days. This drug helps stimulate stem cells to multiply and enter the blood. Then a small tube, called a catheter, is used to get blood from your vein or that of the donor. This is similar to donating blood, but takes several hours. The blood goes to a cell separation device to remove the stem cells needed, which are then frozen and stored for later use. The rest of the blood is returned to you or the donor. This process may need to be repeated more than once.
Receiving the transplant
Here’s a general overview of what happens during a transplant:
During the next few days, you may receive total body radiation or additional high dose chemotherapy. During the total body radiation, you will have protective shields over your lungs, heart, and kidneys.
You then have to wait for the stem cells to get into the bone marrow and start multiplying. You may have to remain in isolation to help prevent infections. Usually, once part of your white blood cell count, called the absolute neutrophil count (ANC), reaches 500, you can come out of isolation. Once it reaches 1,000, you can return home. This typically takes about three weeks.
If you relapse after an allogeneic stem cell transplant, you may have a treatment called donor lymphocyte infusion (DLI). The goal is to put your disease back into remission or to keep it there. Remission is when there is no longer a sign of the disease. This treatment involves removing lymphocytes (a type of white blood cell) from the original stem cell donor’s blood and freezing them. The lymphocytes are later thawed and given to you in one or more infusions. The lymphocytes will see your cancer cells as not belonging to your body and will attack them.
What to expect after a stem cell transplant for CML
The early side effects of a stem cell transplant are from the high-dose chemotherapy and radiation, not the transplant. These should go away as you recover from the transplant. You may also experience a strange taste in your mouth from the preservative used to freeze the stem cells. These are some common side effects:
Some side effects may be long-lasting or appear years later. These are possible long-term side effects:
Shortness of breath, often caused by radiation damage to the lungs
Skin rashes with itching, severe diarrhea, fatigue, and muscle aches. These symptoms may indicate graft-versus-host disease (GVHD), a condition that occurs if the immune system cells from the donor attack your skin, liver, gastrointestinal tract, mouth, or other organs. GVHD can occur only after an allogeneic (donor) transplant, not an autologous transplant. GVHD can be serious, sometimes even life-threatening, and may require treatment with immune-suppressing drugs.
Lack of menstrual periods, which may indicate ovary damage and cause infertility
Vision problems, such as blurriness or cloudiness, caused by damage to the lens of the eye
Bone pain caused from damage due to lack of blood supply to the bone called aseptic necrosis