Photo by Todd McNaught
Many patients who undergo bone-marrow or stem-cell transplantation experience a decline in mental skill and physical coordination after treatment. A new study led by scientists in the Clinical Research Division shows that these effects are largely temporary and that most patients can expect a return to normal function within a year of their transplant.
Any lingering physical or mental impairments likely are not the result of the transplant process for most patients, according to a study published in the July 13 issue of Blood.
"In all areas except coordination, function is back to normal within a year. Most people do recover well from their transplant treatment," said Dr. Karen L. Syrjala, head of the center's biobehavorial sciences group and lead author of the study.
Researchers know that the powerful chemotherapy drugs leukemia and lymphoma patients take to prepare for bone-marrow or stem-cell transplantation — or later to fight graft-vs.-host disease — can impair neurocognitive function. What hasn't been known, until now, is whether impacts such as decreased memory or the ability to write with a pencil are long lasting.
The results of this study have major implications for advising health-care professionals, patients and their families about expectations after transplant. Overall, the authors concluded that providers can confidently advise patients that while short-term neurocognitive effects of chemotherapy can be severe, most patients return to their pretransplant levels of cognitive function by one year after transplant.
Syrjala and colleagues from the University of Washington departments of Psychiatry and Behavioral Sciences and Rehabilitation Medicine conducted what they believe was the first prospective, longitudinal research to determine the long-term effects of transplantation on cognition and coordination. Impetus for the study was patient complaints of cognitive difficulties following bone-marrow or stem-cell transplantation.
Patients reported problems
"We were hearing from patients that they thought their brains weren't working the same way they did before their transplant," Syrjala said.
"Some patients were reporting difficulties with memory and concentration, for example. Cancer patients often call this 'chemo-brain.' We didn't know if this was part of the normal aging process or a result of their treatment. And we wanted to know if they got better after treatment was finished."
The researchers gave a series of neuropsychological tests to 142 patients at Fred Hutchinson who were about to undergo an allogeneic (from another donor) hematopoietic cell transplant. The same tests were administered 80 days after transplant and again at one year. The tests examined a range of functions from gross and fine motor strength to cognitive flexibility and verbal fluency, and were adjusted for age, gender and education.
The results showed that performance on all the tests declined from pretransplant to 80 days after transplant. By one year, the patients had returned to their pretransplant levels of attention, speed of information processing, learning, visual-motor integration, verbal fluency and verbal memory. In contrast, grip strength and motor dexterity remained below pretransplant levels at one year.
Although verbal skills returned to pretransplant levels, verbal test scores generally were below population norms.
The researchers concluded that long-term cognitive problems were likely related to disease or treatment effects that occurred before transplant. On the other hand, coordination and strength difficulties at one year were related to transplant treatments. Many patients remain on medications at one year. Researchers hypothesized that these patients will continue to improve as they complete their treatments. The researchers are following the patients up to five years after treatment to find out whether they continue to improve.