New Hutchinson Center Study Helps Lift the Fog on Chemobrain

May 6, 2011
Ignacio Lobos
Ignacio Lobos

Because there has been little empirical evidence to back up patients’ stories, chemobrain has been met with skepticism by the medical community and has been a painful puzzle for many patients who couldn’t quite put a name to what they were feeling. This cognitive impairment-characterized by loss of memory and stumbling on words, among other symptoms-has come to be known as “chemobrain” or “chemofog.”

ABSTRACT: Petri Dish is a blog written and produced by the external relations and communications staff at Fred Hutchinson Cancer Research Center. The blog delivers science and biomedical information to the world by highlighting and illuminating the scientific research at the Hutchinson Center and events and general happenings relevant to the center and our larger community.

Last summer, Colleen Steelquist, a science editor at the Hutchinson Center, wrote about many cancer survivors who felt as if their brains were trapped in a fog after treatment.

This cognitive impairment-characterized by loss of memory and stumbling on words, among other symptoms-has come to be known as “chemobrain” or “chemofog.”


Dr. Karen Syrjala

But because there has been little empirical evidence to back up patients’ stories, chemobrain has been met with skepticism by the medical community. And it certainly has been a painful puzzle for many patients who couldn’t quite put a name to what they were feeling.

But this week, a new Hutchinson Center study confirms what patients have been reporting all along: among people who undergo a bone marrow or blood stem cell transplant to treat blood cancers, many go on to experience a decline in mental and fine motor skills.

But there’s also good news in the study: chemobrain’s symptoms are largely temporary for most patients, and they are likely to return to normal motor and memory functions within five years.

The Center’s Dr. Karen Syrjala, who led the study, has been trying to confirm whether the powerful chemotherapy agents involved in transplantation also had an impact on motor and memory skills.

“We were thrilled to see that people recovered substantially, but we also were surprised that so many people did continue to have measurable deficits in some areas even after five years,” she said.

This is the first study of its type to follow patients to ascertain whether they recover from cognitive losses, and it builds on earlier work by Syrjala and colleagues.

Syrjala said she was surprised to also discover that for some patients, cognitive problems don’t go away as quickly. She said it’s not known why these conditions persist in some patients, and more research is needed.

One potential culprit: some cancers, especially leukemia and lymphoma, are “whole-body” cancers because blood circulates throughout the body. These diseases may cause their own neurocognitive impacts, in addition to what chemotherapy may contribute.

“The major clinical implication of this research is to assure (transplant) recipients and their health care providers that further progress will occur in their information-processing capacity between one and five years after treatment,” the study said.

“However, it is equally important to validate for long-term survivors that not all (transplant) recipients fully recover neurocognitive function by five years.”

For these patients, the study concluded, there’s a need for continued rehabilitation to deal with any residual deficits of chemobrain.

This article was reprinted from thePetri Dishblog with permission from the Fred Hutchinson Cancer Research Center.