Stem cell transplant is sometimes used to treat people with leukemia. The majority of people with leukemia who undergo stem cell transplant receive an allogeneic stem cell transplant (allo-SCT), which means that the stem cells are harvested from a donor who may be a sibling or other close blood relative of the recipient or an unrelated person who is a good genetic match. Less commonly, an autologous stem cell transplant may be considered. In an autologous stem cell transplant, the stem cells are harvested from the person’s own body.
One purpose of an allogeneic stem cell transplant in leukemia is to compensate for higher doses of chemotherapy that will destroy bone marrow. The transplanted stem cells will form healthy bone marrow, replacing the destroyed cells after chemotherapy is complete. The other purpose of allogeneic stem cell transplant is to trigger a process known as graft-versus-tumor or graft-versus-leukemia effect in which the transplanted cells help attack the cancer cells. In some cases, allogeneic stem cell transplant can cure leukemia.
Allogeneic stem cell transplants are used to treat acute lymphoblastic leukemia (ALL) in adults, but only considered as a treatment for children after a relapse or when chemotherapy is ineffective. Allogeneic stem cell transplants are also used in cases of acute myeloid leukemia (AML), chronic myeloid leukemia (CML), chronic myelomonocytic leukemia (CMML), and juvenile myelomonocytic leukemia (JMML). Stem cell transplants are not commonly recommended to treat chronic lymphocytic leukemia (CLL).
Due to the risk of severe side effects, allo-SCT is most likely to be considered in cases of leukemia that have relapsed, failed to respond to other treatments, or are deemed high-risk based on genetic characteristics. Eligibility criteria for allogeneic stem cell transplants differ based on type of leukemia and individual medical centers, but there are often age limits. In general, a good candidate for allogeneic stem cell transplant is otherwise healthy, has failed on other treatments, and has a closely matched donor.
Allogeneic stem cell transplants carry a significant risk of life-threatening side effects that make it necessary for doctors and people with leukemia to carefully weigh the benefits against the risks of the procedure.
What does it involve?
Most people with leukemia undergo a course of chemotherapy prior to receiving a stem cell transplant. People with ALL often receive radiation therapy before stem cell transplant as well.
In the past, cells for transplant were taken from bone marrow. For this reason, some people still refer to stem cell transplants as bone marrow transplants. However, blood is now the most common source for hematopoietic (blood cell producing) stem cells for transplant in cases of leukemia. Stem cells sourced from the blood may be referred to as peripheral blood stem cells.
For allo-SCT, stem cells are usually harvested from a donor who is a close blood relative, such as a sibling. The donor may also be someone unrelated who is a good genetic match. Blood from donated infant umbilical cords is another potential source for stem cell transplants.
The process of receiving a stem cell transplant is similar to receiving a blood transfusion. Stem cell transplants for leukemia may be administered on an outpatient or inpatient basis. The majority of people will be admitted to the hospital during the stem cell transplant process. Those admitted to the hospital for stem cell transplant can expect to stay two to three weeks during recovery.
During the first weeks of recovery from stem cell transplant, people with leukemia may receive antibiotics and antiviral or antifungal medications to help protect them against infection. They may also require transfusions of red blood cells or platelets (cell fragments involved in the clotting process) to replace those destroyed by chemotherapy. Those who have undergone stem cell transplant for leukemia may also be given hematopoietic growth factors – substances that encourage and speed the growth of blood cells.
After receiving a stem cell transplant, most people with leukemia will receive maintenance medications to sustain the treatment response.
Allogeneic stem cell transplant can extend survival and provide a cure in some people diagnosed with leukemia.
Allogeneic stem cell transplant is the most successful curative treatment for CML. About 90 percent of people with chronic-phase CML who undergo the procedure will be disease-free at five years. In people with accelerated-phase CML, between 40 and 50 percent are disease-free at five years, while 10 to 20 percent of those who receive treatment for CML in the blast phase are alive and cancer-free at five years.
In people with AML who receive an allogeneic stem cell transplant during their first remission, between 30 and 50 percent are living disease-free after five years.
Allogeneic stem cell transplant is the only cure for JMML. Allo-SCT has been shown to cure JMML in about 50 percent of cases.
Allogeneic stem cell transplant can sometimes cure CMML.
One of the most dangerous risks of allogeneic stem cell transplant is graft-versus-host disease (GVHD). In GVHD, the transplanted donor cells attack the host’s tissues. Graft-versus-host disease ranges from mild to potentially life-threatening. Acute GVHD is very dangerous and must be treated with powerful immunosuppressant medications such as corticosteroids. Chronic GVHD may also threaten life, but in milder cases, chronic GVHD may cause limited symptoms and improve overall survival in people who receive allogeneic stem cell transplant for leukemia. For people who receive allogeneic stem cell transplants, the threat of graft-versus-host disease never fully disappears. Those who receive allogeneic stem cell transplants and show signs of GVHD may need to take immunosuppressant medications throughout their lives. Chronic GVHD can cause symptoms that affect the eyes, lungs, liver, digestive tract, genitals, and skin, hair, or nails. In severe cases, GVHD can be fatal.
A combination of allogeneic stem cell transplant, chemotherapy performed before the procedure, and maintenance medications can compromise the immune system. There is a risk for developing serious or even life-threatening infections.
Short-term side effects of stem cell transplant can include fatigue, headaches, fever and chills, nausea, vomiting, diarrhea, loss of appetite, weight loss, trouble sleeping, and skin rashes. Some people develop mucositis, inflammation of the digestive tract that can cause pain and make it difficult to eat. Some side effects, such as nausea, can be eased with other medications. Fatigue may be longer-lasting, persisting beyond the immediate recovery period. It may take months to fully recover after receiving a stem cell transplant.
In some people, leukemia fails to respond to stem cell transplant and relapses soon after the transplant.
For more details about this treatment, visit:
Acute myelogenous leukemia – Canadian Cancer Society
CML: Stem Cell Transplantation – Leukemia & Lymphoma Society
ALL: Stem Cell Transplantation – Leukemia & Lymphoma Society
AML: Stem Cell Transplantation – Leukemia & Lymphoma Society
Stem Cell Transplant for Acute Myeloid Leukemia (AML) – American Cancer Society
CMML: Stem Cell Transplantation – Leukemia & Lymphoma Society
JMML: Treatment – Leukemia & Lymphoma Society
Stem Cell Transplantation – Leukemia & Lymphoma Society
Graft-Versus-Host Disease – Leukemia & Lymphoma Society https://www.lls.org/treatment/types-of-treatmen...
What are the Side Effects of a Stem Cell Transplant? – Dana-Farber Cancer Institute https://blog.dana-farber.org/insight/2018/02/si...