Stem cell transplant for acute myeloid leukemia

A stem cell transplant replaces stem cells. It uses chemotherapy at very high doses to kill all of the cells in the bone marrow. This includes both healthy cells and cancer cells. Sometimes whole body radiation therapy is also used. After high-dose chemotherapy, healthy stem cells are given to replace the ones in the bone marrow that were killed.

Stem cells are found in the bone marrow, blood and umbilical cords. They are basic cells that develop into different types of cells that have different jobs. For example, all our blood cells develop from blood stem cells.

This treatment is used to replace stem cells when stem cells or bone marrow or both are damaged. A stem cell transplant is very risky and complex, and it must be done in a special transplant centre or hospital.

You may be offered a stem cell transplant to treat acute myeloid leukemia (AML):

• during the first complete remission
• after an early relapse and second complete remission is reached

The following types of stem cell transplant may be used with AML.

The stem cells are taken from one person (the donor) and given to another person (the recipient). The donor and recipient may or may not be related. The donor and recipient are matched through a process called human leukocyte antigen (HLA) typing.

An allogeneic transplant is the most common type of stem cell transplant used to treat AML. But not everyone can have an allogeneic transplant because they need to have a matched donor.

A mini-transplant uses lower doses of chemotherapy or radiation therapy before the transplant. The lower doses don't completely destroy the recipient's bone marrow, so blood cell counts don't drop as low as they do in standard stem cell transplants. Healthy stem cells are then given. Over time, the donor cells take over the bone marrow and replace your own bone marrow cells. A mini-transplant may also be called a reduced-intensity allogeneic transplant or non-myeloablative transplant.

A mini-transplant has a lower risk for complications and can be used for older adults who can't tolerate the higher doses of chemotherapy and radiation normally used with stem cell transplants. People in this age group may also have other health conditions that won't allow them to have an allogeneic transplant.

A half-matched (haploidentical) stem cell transplant is a newer type of stem cell transplant. To do a stem cell transplant, the donor and recipient are matched through a process called human leukocyte antigen (HLA) typing. Usually the antigens on the donor’s and recipient’s stem cells need to be a perfect or nearly perfect match. But a half-match stem cell transplant can be done if only half of the donor’s and recipient’s stem cells match. All parents and children, and about 50% of siblings, are half-matched. A half-matched stem cell transplant may be an option for adults with AML who do not have a matched donor.

A cord blood stem cell transplant uses stem cells collected from blood in the placenta and umbilical cord of newborn babies. Cord blood seems to be a good alternate source for stem cells for people who don’t have a suitable related or unrelated donor. Cord blood stem cell transplants are also linked with a lower risk of a life-threatening condition called graft-versus-host disease (GVHD).

A donor lymphocyte infusion (DLI) may be given if AML relapses after a stem cell transplant. The lymphocytes usually come from the original stem cell donor. DLI causes an intense immune reaction against the AML cells. It may be able to remove leukemia cells that are still in the blood and bone marrow.

Side effects of stem cell transplant will depend mainly on the type of chemotherapy or drug combination given, if radiation therapy was given, the type of transplant and your overall health. Tell your healthcare team if you have side effects that you think are from a stem cell transplant. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Side effects of a stem cell transplant include:

• low blood cell counts, which can cause infection, bleeding and anemia
• graft-versus-host disease (GVHD)
• veno-occlusive disease (VOD)
• digestive system problems, including sore mouth and throat, loss of appetite and diarrhea
• skin problems
• pain
• organ problems, such as kidney, lung or heart problems
• fertility problems
• graft failure or graft rejection
• osteoporosis
• a second cancer

Find out more about a stem cell transplant and side effects of a stem cell transplant. To make the decisions that are right for you, ask your healthcare team questions about a stem cell transplant.