There are two basic types of stem cell transplants and several good sources for these cells. You and your doctor will decide together on the best choice for you. The main types are:
Autologous ("Auto") Stem Cell Transplant
Advantages: Less risk of rejection or graft-versus-host disease, in which the new donor cells think your cells are foreign and attack them. Quicker engraftment. Fewer side effects.
How It Works:
- Your own stem cells are collected, frozen, and stored.
- You have "conditioning treatment" with chemotherapy and possibly radioimmunotherapy to kill the cancer cells and the immature stem cells left in your bone marrow.
- Your previously collected stem cells are thawed and transplanted back into you.
In a tandem (double autologous) transplant, you go through the above process twice instead of once, with a three- to six-month break in between. For multiple myeloma, a tandem transplant has a slightly higher success rate than a single transplant. However, recent clinical trials show that using your own cells once, followed by reduced intensity conditioning treatment and then a transplant from a sibling, offers even longer remissions than tandem.
Allogeneic ("Allo") Stem Cell Transplant
This type of transplant uses a donor's stem cells, either from a relative or a volunteer registered with the National Marrow Donor Program or other registry. It is less common than autologous transplants. It's used for many leukemias, aggressive lymphomas, and failed autologous transplants.
Advantages: The transplanted stem cells are cancer-free. Because the transplant creates a new immune system, the cancer-killing effect continues after the transplant.
Disadvantages: Your body may see the donor stem cells as foreign and reject or react against them. Slower engraftment. More side effects
How It Works:
- The stem cells come from the bone marrow or peripheral stem cells of a matched donor or from umbilical cord blood.
- You receive conditioning treatment with chemotherapy and radiation. This kills the cancer cells and destroys or weakens your own immune system so the donor's immune system can take over.
- You receive the transplant of the donor stem cells.
Sources of Stem Cells for Transplants
Here's a summary of how stem cells from different sources are harvested.
- Your own peripheral cells (stem cells in your bloodstream)
- The blood is collected in three to five appointments when your cancer is not active.
- The blood is spun in a machine like a centrifuge to separate the stem cells.
- The stem cells are purged or cleaned to remove any remaining cancer cells.
- You receive back the other portions of your blood.
- The stem cells are frozen to be placed back into your body after you have had chemotherapy and/or radiation.
- Enough cells are usually collected for two transplantation procedures, especially for multiple myeloma.
- Your own bone marrow
- Stem cells are taken from a site near your hip, under general anesthesia. (This is rarely done in autologous donation.) This is not commonly performed anymore.
- Donor peripheral cells
- Peripheral stem cells from another person are collected from blood drawn over two to three days.
- The blood is spun in a machine like a centrifuge to separate the stem cells, and then the donor receives back the other portions of blood.
- Donor bone marrow
- Stem cells are taken from the donor's hip under general anesthesia. This is not commonly performed anymore.
- Umbilical cord blood
- In the past few years, more parents have been donating their children's umbilical cords to cord banks. Because the blood in an umbilical cord contains immature stem cells, a partial match can be made from this blood. Adults may need more than one cord donation to get enough stem cells for a transplant.
How do you decide which type and source is right for you? There are many factors, which you must discuss with your doctor:
- The type and stage of your disease
- Your age and overall health
- The amount of damage to your own bone marrow caused by earlier chemotherapy/radiation
- Whether you have siblings or will need a non-related donor or umbilical cord blood