Patients who suffer a loss of cognitive and motor function as a result of stem cell transplantation for severe blood disorders are likely to see those functions return to previous levels after one year, according to a new study in the November 15, 2004, issue of Blood, the official journal of the American Society of Hematology.
Researchers from the Fred Hutchinson Cancer Research Center and the University of Washington School of Medicine studied 142 patients who had blood disorders, such as chronic myeloid leukemia, myelodysplasia, and myelofibrosis, and who underwent hematopoietic cell transplant (a procedure to replace cancerous cells with new, healthy ones).
In preparation for the transplant, patients underwent high-dose chemotherapy to destroy their diseased bone marrow. Some of the drugs used for this purpose are known to have neurotoxic effects. In addition, medication to decrease the toxicity of the transplant to normal tissues, termed graft-versus-host disease (GVHD), may also lower neurocognitive function.
To test the extent of this type of damage, each patient's cognitive and motor functions, such as problem solving, memory, motor speed and dexterity, attention, and word association, were tested before, 3 months after, and 1 year after the transplant. At three months after transplant, patients experienced a significant decline in all the functions tested. By one year, however, the neuromotor functions for most patients had come back to the level experienced before the transplant, with the exception of two capabilities: grip strength and motor dexterity.
The study also uncovered factors which lowered the risk of patients having impaired neuromotor function. Patients who had no chemotherapy or chemotherapy with only hydroxyurea prior to the transplant and those who did not receive certain immune suppressants (cyclosporine, tacrolimus, or mycophenolate mofetil) to ward off GVHD were better off.
At one year, 70 percent of patients were still receiving treatment for GVHD. Therefore, further improvement might be expected beyond one year as patients continue to recover and are able to discontinue medications.
"The results of this study have important implications for physicians and patients when they have choices about treatments for these diseases. The most immediate value is for patients and their families to know what they can expect after hematopoietic cell transplant," according to Karen Syrjala, Ph.D., head of biobehavorial sciences at the Fred Hutchinson Cancer Research Center and lead author of the study.