Biologic vs physiologic age in the transplant candidate.

Hematopoietic cell transplantation (HCT) remains a cornerstone of treatment of many hematologic malignancies but transplant-associated morbidity and mortality limit application to older patients. Biologic or chronologic age barriers to HCT have fallen, because patients in their 8th decade of life comprise the group with the greatest rise in transplant use over the past decade. Evaluating physiologic age or general health in older transplant candidates requires a systematic approach inclusive of functional and comorbidity assessment, which typically is accomplished through geriatric assessment (GA). GA incorporates measures of comorbidity, function, nutrition, social support, and other health-related domains to better describe physiologic age. Older allogeneic transplant patients have a surprisingly high prevalence of vulnerabilities by GA prior to transplant, and significant comorbidity or functional limitations heighten the risks of transplant-related mortality. Ultimately, incorporation of physiologic age can improve estimates of nondisease life expectancy, prognostic survival after HCT, and inform HCT candidacy. Future research on the optimal tools to characterize physiologic age and appropriate interventions in the context of transplant are needed.