Frailty: the missing piece of the pre- hematopoietic cell transplantation assessment?

Hematopoietic stem cell transplantation (HSCT) represents a curative option for those afflicted with numerous hematologic malignancies and bone marrow failure syndromes. Advances and refinement of the HSCT process have resulted in increasing number of transplants performed on older patients in the recent years. Pre-transplant assessments (PTA) function to risk stratify patients prior to undergoing HSCT in an effort to predict those at higher risk of treatment-related toxicity, to inform risk/benefit assessments and to aid clinical decision making. Traditionally used risk stratification parameters such as chronologic age, comorbidity and performance status may not fully capture physical function, physiologic fitness, highlighting a need for improvement in PTA. Incorporation of frailty measurements in pre-HSCT assessments, particularly in elderly transplant candidates, may result in improving predictive ability of existing tools such as the Hematopoietic Cell Transplantation Comorbidity Index and Karnofsky performance status. Here, we review existing pre-HSCT assessment tools, measures of frailty that may aid in risk stratification for patients undergoing HSCT and directions for future research using frailty in the pre-HSCT setting.