Late cognitive outcomes among allogeneic stem cell transplant survivors: follow-up data from a 6-year longitudinal study.

CONTEXT Survivors of allogeneic hematopoietic stem cell transplantation (alloHCT) may experience cognitive impairment over time post-treatment, but early identification of these individuals is limited. OBJECTIVES We previously reported a prospective evaluation of cognitive functioning over the first 6 months of alloHCT. Here, we report an extension of this study, with specific aims to (1) evaluate the trajectory of cognitive outcomes over the first 6 years post-alloHCT, and (2) determine the extent to which late cognitive impairment is predicted by earlier impairment. METHODS Participants completed objective and subjective cognitive measures before alloHCT, and at 100 days, 6 months, and 6 years post-alloHCT. Outcome trajectories were determined using linear mixed effects models. Relationships between early and late cognitive impairment were assessed using logistic regression and receiver operator curves. RESULTS This analysis is based on longitudinal data from 59 participants, of whom 20 provided data at 6-year follow-up. Longitudinal models revealed an overall stability of cognitive outcomes over time, except for psychomotor efficiency/processing speed performance, which significantly improved (p = .049). However, poor learning/memory and cognitive complaints were persistently observed. At 6 years, 40% of relapse-free survivors met the impairment criteria. Impairment at 100 days was associated with impairment 6 years (OR = 20.00, p = .028) and demonstrated good accuracy in classifying those who were impaired and not impaired at 6 years (AUC = .79; 95% CI = .56-1.00). CONCLUSION Poor cognitive outcomes among long-term alloHCT survivors are associated with cognitive functioning during the early post-treatment period. Early identification of survivors likely to experience poor cognitive outcomes may be possible, enabling timely intervention to mitigate long-term negative impacts.