Up-to-date tools for risk assessment before allogeneic hematopoietic cell transplantation

Cure of malignant and non-malignant hematological diseases is potentially possible after allogeneic hematopoietic stem cell transplantation (HCT). Accurate evaluation of the risk-benefit ratio for an individual patient could improve the decision-making process about transplant, which ultimately would increase the likelihood of success. Several transplant-related models were designed in an effort to optimize decision-making about suitable candidates for allogeneic HCT. In 1998, The European Society for Blood and Marrow Transplantation (EBMT) developed a five-component pretransplantation risk scoring system for patients with CML. The EBMT score was later tested in patients with various hematological disorders, and it was shown to stratify risks of mortality after allogeneic HCT. More recent research efforts focused on models that assess health status before HCT. A HCT-specific comorbidity index was designed to assign weights to 17 relevant comorbidities that were shown to independently predict non-relapse mortality. Performance status scales and comprehensive geriatric assessment tools might uncover additional overall health limitations that affect long-term survival among older recipients of allogeneic HCT. Other models include the pretransplantation assessment of mortality score that summarizes the impacts of eight different pretransplantation patient- and disease-specific variables into a 50-point model that predicts survival. The disease-risk index captures the impact of primary diagnoses and disease status on relapse and survival following allogeneic HCT. The values and limitations of each model are discussed herein. We also provide insight on how to use these models in the clinic to decide about offering allogeneic HCT with the most suitable conditioning regimen intensity.