Photo by Chad McNeeley
HSCT preparation
New research suggests the risk of cognitive impairment after hematopoietic stem cell transplant (HSCT) is greatest among recipients of myeloablative allogeneic (allo) HSCTs.
Compared to healthy controls, patients who received myeloablative allo-HSCT had a significantly higher risk of global cognitive deficit at a few time points after transplant.
There was a trend toward increased global cognitive deficit in recipients of allo-HSCT who had reduced-intensity conditioning (RIC), but there was no increased risk of global cognitive deficit in recipients of autologous (auto) HSCT.
Researchers reported these findings in the Journal of Clinical Oncology.
“With this research from our longitudinal prospective assessment, we are able to deduce that a significant population of allogeneic [HSCT] survivors will experience cognitive impairment that can and will impact different aspects of their lives moving forward,” said study author Noha Sharafeldin, MD, PhD, of the University of Alabama at Birmingham.
“And it’s critical that we as clinicians develop interventions for these patients. This research is just the beginning of our figuring out how we can best care for [HSCT] survivors and enable them to live healthy lives.”
This study included 477 patients who underwent HSCT between 2004 and 2014. There were 236 auto-HSCTs, 128 RIC allo-HSCTs, and 113 myeloablative allo-HSCTs.
Patients underwent standardized neuropsychological testing before HSCT as well as at 6 months, 1 year, 2 years, and 3 years after transplant.
There were 429 patients who completed pre-HSCT testing (89.9%), 341 (81.6%) who underwent testing at 6 months after HSCT, 308 (81.5%) at 1 year, 247 (80.7%) at 2 years, and 227 (81.4%) at 3 years.
Testing was conducted on 8 cognitive domains—executive function, verbal fluency and speed, processing speed, working memory, visual and auditory memory, and fine motor dexterity.
The researchers conducted this testing in 99 healthy control subjects as well.
Before and after HSCT
Prior to HSCT, there were no significant differences in the cognitive domains tested between auto-HSCT recipients and controls or between RIC allo-HSCT recipients and controls.
Recipients of myeloablative allo-HSCT had significantly lower pre-HSCT scores for processing speed (P=0.001), as compared to controls.
After HSCT, there were no significant differences in overall scores between auto-HSCT recipients and controls or between RIC allo-HSCT recipients and controls.
However, recipients of myeloablative allo-HSCT had significantly lower scores than controls for executive function, verbal speed, processing speed, auditory memory, and fine motor dexterity (P≤0.003 for all).
Outcomes over time
For auto-HSCT recipients, there was a significant improvement from pre-HSCT to 6 months post-HSCT in verbal fluency (P<0.001). Meanwhile, there was a significant decrease in verbal processing and fine motor dexterity (P<0.001 for both).
At 3 years, auto-HSCT recipients had a significant increase in verbal fluency (P<0.001) but a significant decrease in visual memory (P=0.001) and fine motor dexterity (P<0.001).
For RIC allo-HSCT recipients, there was a significant decrease from pre-HSCT to 3 years post-HSCT in executive functioning (P=0.003), verbal fluency (P<0.001), and working memory (P<0.001). There were no significant differences between pre-HSCT and 6-month scores.
For patients who received myeloablative allo-HSCT, the only significant difference from pre-HSCT to 6 months or 3 years was a decrease in fine motor dexterity (P<0.001 for both time points).
Global cognitive deficit
There was no significant difference in the prevalence of global cognitive deficit between auto-HSCT recipients and controls before HSCT (22.5% vs 17.2%; P=0.28) or at any time point after—6 months (26.1% vs 16.5%; P=0.07), 1 year (21.4% vs 19.5%; P=0.73), 2 years (21.1% vs 16.4%; P=0.43), and 3 years (18.7% vs 8.7%, P=0.11).
There was no significant difference in the prevalence of global cognitive deficit between RIC allo-HSCT recipients and controls before HSCT (17.2% for both; P=1.0), at 6 months (22.0% vs 16.5%; P=0.35), 1 year (24.1% vs 19.5%; P=0.46), or 2 years (30.6% vs 16.4%; P=0.05) after HSCT.
However, the prevalence was significantly higher for RIC allo-HSCT recipients 3 years after HSCT (35.4% vs 8.7%; P=0.0012).
There was no significant difference in the prevalence of global cognitive deficit between myeloablative allo-HSCT recipients and controls before HSCT (22.3% vs 17.2%; P=0.37) or at 1 year after (28.4% vs 19.5%; P=0.20).
However, the prevalence was significantly higher for myeloablative allo-HSCT recipients at 6 months (31.1% vs 16.5%; P=0.03), 2 years (34.6% vs 16.4%; P=0.02), and 3 years after HSCT (36.0% vs 8.7%; P=0.0015).
“From this data, it’s clear that we have to make strides in supporting allogeneic [HSCT] recipients in their recovery to ensure that we are educating patients and their families on signs of cognitive impairment,” Dr Sharafeldin said. “This data will help us identify patients at highest risk of cognitive impairment and inform the development of interventions that facilitate a patient’s recovery and return to normal life.”