Stem Cell Transplant for Acute Lymphocytic Leukemia (ALL)

A stem cell transplant, also known as a bone marrow transplant, lets doctors give higher doses of treatment to try to cure ALL (acute lymphocytic leukemia, also known as acute lymphoblastic leukemia).

This treatment is intense, and not everyone with ALL is a good candidate for it.

• Note: This information is about treating acute lymphocytic leukemia (ALL) in adults. To learn about ALL in children, see Leukemia in Children.

Why are stem cell transplants used for ALL?

Standard doses of chemotherapy (chemo) or other medicines aren’t always able to cure ALL. Higher doses might be more effective, but these doses can also severely damage your bone marrow (the spongy center of some bones, where new blood cells are formed).

This could lead to life-threatening infections, bleeding, and other problems due to low blood cell counts.

A stem cell transplant (SCT) allows doctors to use these high doses of chemo (sometimes along with immunotherapy and/or radiation therapy) by putting healthy blood stem cells back into your body after your bone marrow has been destroyed by treatment.

During a stem cell transplant, you get an infusion (transplant) of blood-forming stem cells to restore your bone marrow.

When are stem cell transplants used for ALL?

A stem cell transplant is an intensive treatment. It offers the best chance to cure ALL, but it can also have serious side effects. Some of these can even be life-threatening.

Because of this, not everyone with ALL is a good candidate.

Stem cell transplant is more likely to be a good option if you are younger and don’t have other serious health conditions, especially if your ALL has features that put it at higher risk for coming back. It’s also important to find a matched stem cell donor (see below).

When a stem cell transplant is an option, it’s usually done as part of the second (consolidation) phase of treatment, once the ALL is in remission.

See Typical Treatment of Acute Lymphocytic Leukemia (ALL) for more about this phase.

A stem cell transplant might also be an option if the leukemia returns after treatment and can be put into remission again.

Types of stem cell transplant

The main types of stem cell transplant are:

• Allogeneic transplant (the type most often used to treat ALL)
• Autologous transplant (may be an option for some people)

Allogeneic stem cell transplant

This is the type of transplant most often used to treat ALL. In an allogeneic stem cell transplant, the stem cells come from someone else (a donor). They can come from the donor’s:

• Blood (called a peripheral blood stem cell transplant or PBSCT)
• Bone marrow (called a bone marrow transplant or BMT)
• Umbilical cord blood

Bone marrow transplant was more common in the past, but today it has largely been replaced by PBSCT.

Finding a donor

To help prevent the risk of major problems, your donor’s tissue type (HLA type) should closely match yours. You can learn more about HLA matching in Finding a Stem Cell Donor.

A well-matched donor might be:

• A close relative, such as a sibling (often the best option)
• A matched unrelated donor (MUD), if no close relative is a good match (may cause more complications than a related donor)
• Matched umbilical cord stem cells (taken from umbilical cord blood and placenta after a baby is born and the umbilical cord is cut)

If a fully matched donor isn’t available, other options might include:

• A partially matched unrelated donor (called a mismatched unrelated donor, MMUD)
• A half-matched family member (haploidentical donor). This is a close family member (including a parent or child) who shares one-half of your ΗLΑ type.
• Umbilical cord stem cells from a haploidentical or partially matched donor

Reduced intensity allogeneic stem transplant

Allogeneic transplants are not an option for everyone. This type of transplant can have serious side effects, which are often too severe for people who are older or have other health problems.

A reduced intensity transplant might be an option instead. You might also hear this called a reduced intensity conditioning (RIC) transplant, a non-myeloablative transplant, or a mini-transplant.

This type of SCT uses lower doses of treatment that don’t completely destroy the cells in your bone marrow. It relies on the donor cells (instead of the chemo and radiation) to kill the leukemia cells.

This is known as a graft-versus-leukemia effect:

• When the donor immune cells are infused into your body, they see any remaining leukemia cells as foreign and attack them.

Autologous transplant

An autologous transplant isn’t often used to treat ALL. But it may be an option for people who can’t have an allogeneic transplant, either because they don’t have a matched donor or for some other reason.

For an autologous stem cell transplant, your own stem cells are removed from your bone marrow or blood.

• The cells are frozen and stored while you get treatment (high-dose chemotherapy, immunotherapy, and/or radiation).
• The lab may use a process called purging to try to remove any leukemia cells from the samples.
• The stem cells are then put back (re-infused) into your blood after treatment.

Limitations of autologous transplant for ALL

One problem with this type of transplant is that leukemia is a disease of the bone marrow and blood. Even after purging, there is a danger that leukemia cells could be put back in your body along with the stem cells.

Another reason allogeneic transplants are preferred is because of the graft-versus-leukemia effect (see above). This effect doesn’t happen with an autologous SCT.

Deciding to get a stem cell transplant for ALL

A stem cell transplant is an intensive and complex treatment that can cause life-threatening side effects.

If your cancer care team thinks you might benefit from a transplant, it’s important to discuss:

• What kind you will have
• The possible side effects
• How long it may take for you to recover

Stem cell transplants should be done at a center where the staff has experience with the procedure and with managing the recovery phase.