Pediatric Acute Lymphoblastic Leukemia

Hematopoietic Stem Cell Transplantation

Allogeneic
hematopoietic
stem cell
transplantation

Allogeneic hematopoietic stem cell transplantation

In pediatric acute lymphoblastic leukemia (ALL), the achievement of a disease-free survival rate surpassing 85% is possible with standard chemotherapy protocols. Consequently, allogeneic hematopoietic stem cell transplantation is usually reserved for patients who experience a relapse and enter a second remission. Nonetheless, for cases with a poor prognosis where the chance of cure falls below 40% with chemotherapy alone, this form of transplantation might be recommended during the initial remission phase to improve long-term outcomes.

If the patient is an infant under the age of 1 at the time of diagnosis and has an MLL gene rearrangement
If findings such as hypodiploidy (less than 44 chromosomes) or Philadelphia chromosome positivity are present in chromosome tests
If remission induction fails during the first cycle after diagnosis

In pediatric Acute Lymphoblastic Leukemia (ALL), hematopoietic stem cell transplantation is most strongly indicated in scenarios where achieving a cure with chemotherapy alone is challenging. Such scenarios include an early bone marrow relapse, which occurs within 6 months after completing treatment or within 36 months from diagnosis, and cases where there is a failure to achieve initial remission with induction chemotherapy.

Until recently, the disease-free survival rate for pediatric ALL patients who underwent HLA-matched sibling transplantation during their second remission ranged between 32-65%. Outcomes from transplants with non-sibling donors have shown comparable results. However, if the transplantation is carried out during active relapse without achieving a remission state, the success rates drop significantly, often to less than 10%.