Stem Cell Transplants for Leukemia
A stem cell transplant replaces diseased or damaged stem cells with healthy ones. This procedure restores the body’s ability to make blood cells after intensive leukemia treatments. In some cases, transplanted stem cells attack cancer cells. A stem cell transplant is also known as a bone marrow transplant. This highly advanced leukemia treatment only takes place at select medical centers with specialized transplant centers.
How does a stem cell transplant (bone marrow transplant) treat leukemia?
Bone marrow (the soft, spongy substance inside bones) makes billions of stem cells every day. These stem cells develop into oxygen-carrying red blood cells, disease-fighting white blood cells, and blood-clotting platelets. Leukemia and certain leukemia treatments can damage or destroy stem cells, affecting their ability to make blood cells. Low blood cell counts can lead to potentially life-threatening infections, bleeding, and other problems.
A stem cell transplant helps people with leukemia by:
- Restoring the body’s ability to make blood cells: A stem cell transplant takes place after a person undergoes high doses of chemotherapy, radiation therapy, or both treatments to treat aggressive cancers. The goal of these intensive treatments is to destroy as many cancer cells as possible. But the high dosages also wipe out stem cells and may cause bone marrow to stop making stem cells. A transplant replenishes stem cells, helping the body to recover so it can make blood cells again.
- Attacking cancer cells: After high-dose cancer treatments, transplanted stem cells from a donor (known as “the graft”) can attack lingering cancer cells (“the tumor”). This response is known as the graft-versus-tumor, graft-versus-cancer, or graft-versus-leukemia effect.
What are the types of stem cell transplants for leukemia?
The two main types of stem cell transplants for people with leukemia include:
- Allogeneic stem cell transplant: Healthy stem cells come from a donor. The odds of a successful transplant are best when the donor is a close relative like a sibling. A matched unrelated donor (MUD) transplant can also work, but it increases the risk of a complication called graft-versus-host disease (GVHD).
- Autologous stem cell transplant: Donor stem cells come from the person who has leukemia. This type of transplant is only an option when there are enough healthy stem cells to use.
What steps take place during a stem cell transplant (bone marrow transplant)?
Most people with leukemia undergo allogeneic stem cell transplants, receiving healthy stem cells from a donor. The procedure involves:
- Conditioning: The transplant recipient undergoes up to two weeks of high doses of chemotherapy, radiation therapy, or both treatments. These treatments destroy cancer cells to make room in the bone marrow for the donor cells. The treatments also weaken the immune system to lower the risk of transplant (graft) rejection.
- Harvesting: Doctors remove stem cells from bone marrow in a donor’s hip bone. This procedure takes place in an operating room while the donor is under general anesthesia. Doctors can also collect stem cells directly from a donor’s blood. An IV and catheter (flexible tube) send the donor’s blood through a machine. The machine removes stem cells from the blood and returns the filtered blood back to the donor.
- Transplantation (infusion): The transplant recipient receives the donor cells through a central venous catheter. This thin, flexible tube goes directly into a large vein above the heart. An infusion may take one to five hours.
- Engrafting: The transplanted stem cells enter the recipient’s bone marrow, where they start making cancer-free blood cells. During the engrafting period (which can take up to six weeks), the recipient either stays in the hospital or visits the cancer center daily to catch any complications quickly.
- Rehabilitation: It can take up to a year or longer for blood counts to return to normal. Transplant recipients may need daily or weekly examinations and blood tests. Due to low blood counts, many recipients need antibiotics for infections and blood transfusions.
Who needs a stem cell transplant for leukemia?
For some people, a stem cell transplant can improve quality of life. Stem cell transplants may also be helpful in these situations:
- Leukemia comes back after treatments end (cancer relapse).
- There’s a high risk of a cancer relapse after undergoing less intensive treatments.
- Leukemia cells don’t respond to initial treatments (refractory cancer).
- Leukemia cells develop drug resistance during treatments (refractory cancer).
What types of leukemia do stem cell transplants treat?
- Acute lymphoblastic leukemia (ALL)
- B-cell acute lymphoblastic leukemia (B-ALL)
- T-cell acute lymphoblastic leukemia (T-ALL)
- Acute myeloid leukemia (AML)
- Childhood leukemia
- Chronic lymphocytic leukemia (CLL)
- Chronic myeloid leukemia (CML)
- Chronic myelomonocytic leukemia (CMML)
- Myelodysplastic syndromes
How do stem cell transplants cause graft-versus-host disease (GVHD)?
People who receive donor cells through an allogeneic stem cell transplant are at risk for graft-versus-host disease (GVHD). This reaction occurs when the donor cells (graft) view the transplant recipient’s ("host’s”) healthy cells as foreign. The donor cells attack the transplanted cells, which can damage the digestive system, liver, skin, and other organs.
There are two types of graft-versus-host disease:
- Acute graft-versus-host disease
- Chronic graft-versus-host disease
Acute graft-versus-host disease
Acute graft-versus-host disease typically occurs within three to four weeks after a stem cell transplant (but symptoms may appear up to 90 days afterward). It affects up to half of all transplant recipients. Immunosuppressants can lower the risk of acute GVHD, while steroids ease symptoms.
Symptoms of acute GVHD include:
- Burning, red skin rash on the palms of the hands and soles of the feet
- Digestive problems like cramping, diarrhea, and vomiting
- Liver issues that cause jaundice (yellow tint to the skin and eyes)
Chronic graft-versus-host disease
Chronic graft-versus-host disease can occur within three months to two years after a transplant. It causes similar symptoms as acute GVHD, including rash and digestive issues. The rash may itch, blister, and peel. The skin may feel tight. Other symptoms include mouth sores, dry eyes, breathing problems, and burning sensations when eating. Immunosuppressants and steroids can help.
What are other side effects of stem cell transplants for leukemia?
In addition to graft-versus-host disease, a stem cell transplant can cause other side effects. You can take steps to manage these treatment side effects.
Potential side effects of a stem cell transplant include:
- Increased bleeding and bruising, including nosebleeds and bleeding gums
- Lung inflammation (pneumonitis) and infections (pneumonia)
- Mouth sores
- Nausea and vomiting