Stem cells are immature cells that are the "starter" cells for all types of tissues. When you have leukemia, a stem cell transplant may be used to help your body make new healthy blood cells. It replaces the blood stem cells that are killed during high-dose chemotherapy, allowing doctors to give you more intensive treatment. Research is ongoing to find out how helpful stem cell transplantation is for chronic lymphocytic leukemia (CLL).
You should know that stem cell transplants aren't considered the first line of treatment for CLL. When they are used, they are commonly part of a clinical trial. However, your doctor may suggest one in cases like these:
Your leukemia is no longer responding to standard treatments, or the time between the response and when the leukemia returns is short.
Your leukemia has certain prognostic factors that make it likely that it will progress more rapidly.
A stem cell transplant is an intensive procedure that is most likely to be successful in people who are younger and healthy enough to withstand it. Whenever possible, using stem cells from a matched donor is preferred over using your own stem cells. This requires having a matched donor available to provide the stem cells for the transplant. In many cases this may be a family member, but stem cells may also come from a matched, unrelated donor if no family member has the same tissue type as you. It's also important to discuss the procedure thoroughly with your doctor beforehand to make sure you understand the possible risks and benefits.
Although still considered experimental, mini-transplants (also called nonmyeloablative transplants) are sometimes used for people with CLL. People receive a lower dose of chemotherapy and radiation, which doesn't completely destroy the cells in the bone marrow. But it is enough to suppress the immune system. Then people receive donor stem cells, which later develop an immune reaction to the cancer cells, killing them off.
Because this treatment uses lower doses of chemotherapy and radiation, it kills cancer cells with much less toxicity. Older people or those with other health problems can therefore better withstand this treatment.