Comparing the long-term outcomes of umbilical cord blood donor versus unrelated donor transplantation in patients with acute myeloid leukemia.

This study compared the long-term outcomes of umbilical cord (UC) blood transplantation versus unrelated donor transplantation (UD) in patients with acute myeloid leukemia (AML). The data showed that long-term outcomes for patients in complete remission two years after transplantation was not impacted by donor type.

AML is a cancer of the blood and bone marrow leading to abnormal white blood cells. It is often treated with powerful chemotherapy. Although chemotherapy results in remission in many older patients, relapse is common and overall survival is poor. Stem cell transplantation is considered the most effective therapy for adults with high-risk AML who have achieved complete remission after primary or secondary treatment (chemotherapy).

Stem cells can be found in the bone marrow and bloodstream, as well as in the umbilical cords (UC) of newborn babies. Stem cells can be harvested from the patient’s own bone marrow or blood, or they can be harvested from a donor. An allogeneic hematopoietic stem cell transplant (allo-HSCT). involves donated stem cells. Ideally, the donor is genetically similar to the patient, such as a brother or sister.

In some cases, stem cells from a related or an unrelated donor (UD) are used. However, there are few studies comparing the long-term outcomes of UC versus UD transplants in patients surviving free of disease recurrence for at least 2 years.

This study involved 3693 patients with AML who were treated with allo-HSCT. Patients were divided into 3 groups. Group 1 included 364 patients who received grafts from UC blood. Group 2 included 2648 patients who received grafts from UD that were completely similar (10/10). Group 3 included 681 patients who received grafts from UD who were partially similar (9/10). The average follow-up time was 6 years.

The occurrence of relapse 3 years after the transplant was similar between groups (9.8% in group 1, 9.3% in group 2, and 11.3% in group 3). The 5-year average overall survival was 88.6% in group 1, 87.9% in group 2, and 89.9% in group 3. The 5-year average survival without cancer progression or worsening after transplantation was 85.7% in group 1, and 84% in groups 2 and 3.

The factors associated with relapse were higher age at transplantation, second complete remission (CR) versus first CR, secondary AML, and genetic abnormalities associated with a poor-risk disease. The donor type had no impact on overall survival, survival without cancer progression, and relapse rate.

The study concluded that long-term outcomes for patients with AML in CR two years after transplantation were not impacted by donor type.

The patients in the 3 groups were not uniformly divided. Important information like minimal residual disease data, genetic mutations data were missing.