Brain Imaging and Overall Survival after Allogeneic Hematopoietic Cell Transplantation

Aim: We conducted a retrospective review of all brain imaging studies in the first year after allogeneic haematopoietic cell transplantation (HCT) to determine (a) the percentage of patients with CNS neurological complications based solely on undergoing brain imaging, (b) transplant-related risk factors of undergoing brain imaging, and (c) overall survival in the patients with neurological complications compared to those transplant patients who did not have brain imaging.
Methods: Subjects were 543 consecutive recipients (August 2004-August 2007) of allogeneic HCT followed for overall survival for up to 6 years after HCT. Comparisons between patient groups with brain imaging and without brain imaging were tested using the Pearson chi-square test. Survival analyses with outcome time-to-brain-scan started at date of transplant and used Kaplan-Meier methods.
Results: Of 543 HCT recipients, 128 patients (24%) underwent brain imaging during the first year after transplantation. There was a greater risk of brain imaging in unrelated donor transplants and in lymphoid as opposed to myeloid malignancies (respective hazard ratios 1.45 and 1.43, P=0.04). Overall survival was significantly worse in unrelated donor transplants (hazard ratio 1.42, P=0.003) and in cord blood transplants (hazard ratio 1.68, P=0.02). Landmark survival analysis of patients alive 1 year after HCT showed worse survival over the next 5 years in those who had brain imaging in the first post transplant year (P<0.0001).
Conclusion: These results suggest that development of neurological symptoms or a sign sufficient to prompt clinicians to order brain imaging early after HCT identifies a poor prognosis in transplant population.