Blood stem cells are immature cells that are the "starter" cells for all types of blood cells. When you have leukemia, a stem cell transplant helps your body make new healthy blood cells. It replaces the leukemia cells and stem cells that are killed during high-dose chemotherapy, allowing your doctor to give you more intensive treatment. Immune cells derived from the stem cells from a donor also help kill leukemia cells that may have survived the chemotherapy.
This treatment is done less often for chronic myeloid leukemia (CML) since the introduction of the targeted therapies, such as imatinib, but it is still a valuable choice for many people. Stem cell transplants may be expensive. And they have many risks. So many doctors now prefer to take a wait-and-see approach to see how people respond to targeted therapy before doing a stem cell transplant.
You should know that stem cell transplants are controversial. Although they may cure you from CML, the benefit has to be weighed against the risks. And the risks may include dying of complications of the transplant. Your doctor may recommend a stem cell transplant, though, for these reasons:
Your disease is in the chronic phase, targeted therapy is not working, and you're younger than age 60 to 65 (doctors' opinions vary about this). Most people with CML are offered treatment with targeted therapy first. But transplant may be offered if targeted therapy does not work (or stops working), particularly to the youngest people.
Your disease is in the accelerated phase, and you're younger than age 60 to 65. Targeted therapy is less successful for people in the accelerated phase. Although the same is true for transplant.
Your disease is in the blast phase, and you're younger than age 60 to 65. Targeted therapy by itself is unlikely to be effective in the blast phase.
You've thoroughly talked about the risks and potential side effects with your doctor and feel you are willing to proceed.
Stem cell transplants are complex procedures. If you have one, you'll need to see a doctor called a stem cell transplant specialist. And you'll want to be sure to have the procedure done in a hospital that specializes in stem cell transplants. These are hospitals accredited by the Foundation for the Accreditation of Cellular Therapy (FACT).
Another potential choice is a newer treatment called nonmyeloablative transplantation. It may also be called either of these names:
Reduced intensity allogeneic transplant
Lower doses of chemotherapy and radiation are used for a nonmyeloablative transplant. This doesn't completely kill the cells in the bone marrow. But it is enough to suppress your immune system so that you are receptive to stem cells. Then you get donor stem cells, which later develop an immune reaction to leukemia cells, killing them off. Because this "mini-transplant" uses lower doses of chemotherapy and radiation, it is less toxic to your body. This makes it an option for older people or people with illness who would otherwise be unable to get a transplant.
Many doctors still consider mini transplants to be experimental for CML and believe that they are best done as part of a clinical trial.