American Medical Association Family Medical Guide - American Medical Association [376]
Stem Cell and Bone Marrow Transplants
If a closely matched donor is available, a stem cell or bone marrow transplant with very high-dose chemotherapy offers a chance for a cure for some types of cancer and other diseases. Bone marrow is spongy tissue inside the large bones that contains stem cells, which make all the different types of blood cells in the body. The tissue or cells can be taken either from the patient (an autologous transplant) or from a closely matched donor (an allogeneic transplant). A sibling’s tissue is usually the best match, but bone marrow registries can often find unrelated donors who may be good matches for transplants.
Stem Cell Transplants
For an allogeneic stem cell transplant, stem cells can be collected from the donor’s bloodstream using a procedure called apheresis. In apheresis, blood is drawn from the donor with a needle and syringe and put through a machine that collects stem cells from the blood and infuses the rest of the blood back into the person through another vein. Alternatively, stem cells can be taken directly from the bone marrow while the donor is under general anesthesia.
Before receiving the collected stem cells (either your own or those from a donor), you will be given massive doses of chemotherapy (see page 23), perhaps along with radiation therapy (see page 23), to destroy all the cancerous cells in your body.
Bone Marrow Transplants
A bone marrow transplant is used to replace diseased bone marrow with healthy bone marrow. For an al logeneic bone marrow transplant (which uses bone marrow from a compatible donor), all the bone marrow in your body is first destroyed with high doses of chemotherapy, perhaps along with radiation therapy. Healthy marrow that has been taken from the donor is injected through a needle into one of your veins to replace the bone marrow that was destroyed.
For an autologous bone marrow transplant, some of your bone marrow is taken from you, treated with powerful drugs to kill the cancer cells, and frozen until it is needed. You are then given high-dose chemotherapy (and possibly radiation therapy) to destroy all of your remaining bone marrow. After thawing your frozen, treated bone marrow, the doctor injects it back into your body through a needle into a vein to replace your destroyed, cancerous marrow.
After a Stem Cell or Bone Marrow Transplant
Immediately after the stem cell or bone marrow transplant or intensive chemotherapy, you will have virtually no white blood cells and therefore no ability to fight infections. Because of this, you will be placed in a germ-free environment to avoid the possibility of infection. Once the transplanted stem cells or bone marrow begin to produce white blood cells in adequate numbers, this isolation will no longer be necessary because your immune system will have regained some of its ability to resist infections. You will be given medications derived from human proteins called growth factors to stimulate the growth of healthy blood cells.
Death from infection or severe bleeding can sometimes result after a stem cell or bone marrow transplant or high-dose chemotherapy. A complication of an allogeneic transplant may occur when the donor cells recognize the recipient’s tissues as foreign and react against them. To prevent this graft-versus-host response, you will be given immune-suppressing medications for several months or longer after the transplant.
Treatment
If your leukemia is at an early stage, you do not need any treatment. Your doctor will recommend regular checkups to monitor the progression of the cancer, a flu shot (see page 650) every year, and a vaccination against pneumonia (see page 145) every 5 years. You will need treatment, however, once you start having symptoms, such as a significant