Stem cell transplants may be autologous, which means the stem cells come from your own body. They may also be allogeneic, which means the stem cells come from a donor. Doctors often prefer to do an allogeneic transplant if a suitable stem cell donor can be found. Doctors do an autologous transplant when it's hard to find an exact match from a donor. It may cause fewer side effects, but there is also concern that the stem cells from your own body could be contaminated with leukemia cells, even after treatment in a lab. Discuss the risks and benefits with your doctor. It's often best to wait for an induced remission and for the chemotherapy side effects to wear off before proceeding, if possible. Here's a description of how doctors do a stem cell transplant:
First, your doctor will remove stem cells. Doctors usually retrieve them during a process called apheresis. It involves receiving a growth factor drug by injection for several days. This drug helps stimulate stem cell production and migration from the bone marrow into the bloodstream. Then a small tube, called a catheter, is used to obtain 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. Then the extra blood is returned to you or the donor. You may need to have this process repeated more than once. The stem cells are then frozen until needed later.
An alternative procedure requires retrieving stem cells from the bone marrow of either you or your donor. You or the donor receive general anesthesia. 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.
You are admitted to the hospital the day before your transplant. Your doctor or nurse goes over ways to reduce your risk of infection, such as how to keep your gown sterile and how to prepare your food after the transplant.
After the chemotherapy and/or radiation therapy is finished, you receive the stored stem cells through a needle in your arm that's attached to a tube. This is similar to a blood transfusion.
You then wait for your stem cells to start multiplying. You may need to remain in isolation to help prevent getting an infection. Once the part of your white blood cell count called the ANC reaches 500, you can usually come out of isolation. Once it reaches 1,000, you may be able to return home.
You will need to have a standard tube of blood withdrawn daily to monitor your blood cell count for the next several weeks. You can do this on an outpatient basis.
Mini-transplants, also called nonmyeloablative transplants, are sometimes used for people with acute myeloid leukemia who could not tolerate a standard stem cell transplant. For it, you receive a lower dose of chemotherapy or radiation. This doesn't completely destroy the cells in your bone marrow, but it is enough to suppress your immune system. Then you receive donor stem cells. These later develop an immune reaction to the cancer cells, killing them off.
This treatment uses lower doses of chemotherapy or radiation. Therefore, it kills cancer cells with much less toxicity. Older people or those with other health problems can better withstand this treatment.