Allogeneic Hematopoietic Stem Cell Transplantation in Therapy Related Acute Leukemia.

Therapy related acute leukemia consists of a unique subset of acute leukemia with an increased frequency of high risk cytogenetic and molecular abnormalities, dismal response to therapy, higher relapse rates and poor overall survival. Therapy related acute myeloid leukemia (t-AML) is a better defined disease entity than therapy related acute lymphoid leukemia (t-ALL). However, in recent times, t-ALL is also being increasingly recognized and extensively studied. Therapy related acute myeloid leukemia is usually classified together with therapy related myelodysplastic syndrome. However, the management of these two diseases maybe different regarding needs of induction chemotherapy and eligibility for upfront allogeneic hematopoietic stem cell transplantation (Allo HSCT). There is also evidence regarding differences in prognosis and outcomes between these two entities. Allo HSCT offers a potential for cure in t-AML and t-ALL. However, existing literature on the same is confounded by inclusion of t-MDS and secondary acute leukemias. Here we review the current evidence on the outcomes and predictors of outcomes of Allo HSCT in the management of therapy related acute leukemias. We also shed light into the under-representation of therapy related leukemias in clinical trials. This stresses the need for prospective trials incorporating measurable residual disease monitoring and sequential next generation sequencing based genomic data for accurate prognostication and management of therapy related acute leukemia.