Predictors of Outcomes in Adult Patients with Therapy Related Acute Myeloid Leukemia Undergoing Allogeneic Hematopoietic Stem Cell Transplant - Twenty Year Experience from a Tertiary Care Centre

Background Therapy related acute myeloid leukemia (t-AML) constitutes a subset of AML that has an increased proportion of high risk cytogenetic and molecular features, poorer response to therapy, higher relapse and decreased overall survival. Allogeneic hematopoietic stem cell transplantation (HSCT) offers a potential for cure in t-AML, with survival up to 40% at 2 years. Most studies on HSCT in t-AML have limited number of patients and are confounded by the inclusion of patients with secondary AML and t-MDS. We aim to report our 20-year experience of HSCT in t-AML. Patients and Methods All cases of t-AML who underwent HSCT at our centre from June 1999 to July 2019 were reviewed. Demographic characteristics, prior malignancy, cytogenetic and molecular characteristics of AML, induction treatment received, transplant details as well as post-transplant complications were collected. Primary outcome evaluated was overall survival and secondary outcomes were relapse rate and relapse free survival (RFS). Predictors of survival was identified using Cox-proportional hazards regression model. Results Fifty-two patients underwent HSCT for t-AML. 58% were male (n=30) and median age at HSCT was 55.5 years. Performance status prior to transplant was ECOG score 0/1 in 71.2% (n=37) and score 2 in 28.8% (n=15) patients. Myeloablative conditioning was given for 30.8% (n=16) and reduced intensity conditioning was given for 69.2% (n=36) patients. Transplant related mortality before day+100 was 21.1% (n=11). Acute and chronic GVHD occurred in 61.5% (n = 32) and 28.8% (n=15) patients respectively. Cumulative incidence of relapse at 2 years was 17.3%. OS and RFS at 2 years were 44.1% and 41.3% respectively (Figure 1 a,b). Significant predictors of reduced OS (Figure 2 a,b,c) after day+100 of HSCT by Cox regression were ECOG performance status 2 (Hazard ratio(HR) Ð 6.1), GVHD prophylaxis CSA/methotrexate (HR Ð 4.5) and haploidentical donor transplantation (HR Ð 34). Cytogenetic risk stratification (ELN 2017) was a predictor of OS in univariate analysis but not in multivariate regression analysis. Conclusions Patients with favourable cytogenetic profile, good performance status and having HLA matched donor may have better outcomes after allogeneic HSCT in t-AML. However, overall outcomes of patients with t-AML remain suboptimal and more research is needed in this sub-group of AML.