The impact of second allogeneic hematopoietic stem cell transplantation as salvage therapy for hematologic diseases after a first allogeneic transplantation

Background and objectives: Acute leukemia patients who relapse after the first allogeneic stem-cell transplantation (HSCT1) have a poor prognosis. Second allogeneic hematopoietic stem-cell transplantation (HSCT2) is a therapeutic option for patients with acute myeloid leukemia (AML)/acute lymphoblastic leukemia (ALL) relapsing after HSCT1. Our aim is to evaluate the efficacy of HSCT2 in acute leukemia patients who relapsed after HSCT1. Material and methods: In the current study, we retrospectively analyzed the data of 72 patients who underwent HSCT2. Forty-six patients with AML and 26 patients with ALL were included in the study. Results: Before undergoing HSCT2, 47 % of patients were in complete remission. Median follow-up was 8 (1-109) months. Mortality at last follow-up was 61.1 %, and the median overall survival was 11 months (95 % CI: 1-22.9). Univariate analysis identified that age, Eastern Cooperative Oncology Group (ECOG), Body Mass Index, chimerism, conditioning regimen, CD34+ infused cell count, post-transplant cyclophosphamide usage, disease type, pre transplant hemoglobin-lymphocyte-lactate dehydrogenase-ferritin might be significant factors. After multivariate analysis ECOG (HR: 2.142; 95 % CI: 1.061-4.326; p = 0.034) was the only independent predictor for survival. Conclusion: HSCT2 remains a feasible but high-risk treatment option for patients with relapsed acute leukemia after HSCT1. Our findings confirm that ECOG performance status is a key determinant of survival despite advances in transplantation techniques.