Prognostic Factors Contributing to the Survival of Hematopoietic Stem Cell Transplantation in the General Population with Leukemia: a Systematic Review

Purpose: Hematopoietic stem cell transplantation (HSCT) offers new hope for improving the outcome of leukemic patients who have failed chemotherapy or irradiation therapy. To our knowledge, there was no comprehensive systematic review discussing the prognostic factors for a successful HSCT. We conducted a systematic review to summarize all survival prognostic factors in leukemic patients receiving HSCT as a reference for personalized cancer therapy. Methods: A systematic literature search was performed using PubMed and ScienceDirect databases. The bias and qualities of the studies were assessed using Cochrane risk-of-bias tool and the Newcastle–Ottawa scale (NOS) after assessing the duplicated publication, studies inclusion, and exclusion. The protocol used in this study was registered in PROSPERO. Results: Six cohort studies from 3 continents (America, Europe, and Asia) were selected. The survival outcome parameters included in our review were overall survival (OS), graft versus host disease (GVHD) relapse-free survival (GRFS), disease-free survival (DFS), non-relapse mortality (NRM), progression-free survival (PFS), and relapse incidence (RI). Our analysis found that 12 prognostic factors contributed to HSCT survival were age, gender, donor type, human leucocyte antigens (HLA) matching status, disease type, disease risk, cytomegalovirus (CMV) serostatus, Kanofsky/Lansky score, patient comorbidity, HSC source (peripheral blood vs bone marrow), immune marker, and GVHD prophylaxis. HSC source was the only factor among all prognostic factors that contribute to varied HSCT outcomes. HSCT with bone marrow–derived hematopoietic stem cells (BM-HSCs) resulted in superior outcomes than those from peripheral blood (PB)-derived HSCs, in terms of OS, GVHD, and GRFS. Conclusion: 12 prognostic factors significantly contributed to HSCT survival in patients with leukemia. The different HSC sources resulted in conflicting outcomes among the selected studies, thus opening up an opportunity for future studies with a larger number of patients. By anticipating these factors, physicians can reduce unwanted outcomes and increase patients’ quality of life through HSCT. Lay Summary: This paper summarizes all survival prognostic factors in leukemic patients receiving hematopoietic stem cell transplantation (HSCT) as a reference for personalized cancer therapy. Based on the data from 4 retrospective and 2 prospective cohort studies across 3 continents (America, Europe, and Asia), it was found that 12 prognostic factors contributed to the survival rates after HSCT were recipient/donor age, gender, donor type, HLA-matching status, disease type, disease risk, comorbidity, cytomegalovirus serostatus, Kanofsky/Lansky score, immune markers, HSC source, and graft versus host disease prevention. Disease risk and source of HSC were the most discussed significant factors (3 studies), followed by age, gender, type of leukemia, comorbidities, and Karnofsky score (2 studies). Almost all of the prognostic factors discussed above have been confirmed to have similar outcomes by multiple studies. However, the difference in HSC sources still has conflicting results between studies, suggesting the necessity of future studies with a larger number of patients. By anticipating these factors, physicians can reduce unwanted outcomes and increase patients’ quality of life through HSCT.