By Charlene Laino
WebMD Health News
Reviewed by Louise Chang, MD
Nov. 29, 2012 (Chicago) -- For cancer patients undergoing chemotherapy who have found their complaints of general mental fogginess and haziness dismissed by their doctors as not being a real medical condition, vindication has arrived.
Using brain imaging, researchers have found physiological evidence of "chemo brain," the problems with memory, concentration, and planning that often plague cancer patients during treatment with chemotherapy drugs.
A combination of positron emission tomography and computed tomography (PET/CT) showed chemotherapy can induce changes in the brain that may affect concentration and memory, says researcher Rachel A. Lagos, DO, a resident in diagnostic radiology at the West Virginia University School of Medicine and West Virginia University Hospitals in Morgantown.
"We were surprised at how obvious the changes were," Lagos says. "Chemo brain phenomenon is more than a feeling. It is a change in brain function observable on PET/CT brain imaging."
Chemo Fog Common
In a 2006 study, University of Rochester researchers found that 82% of 595 people with cancer given chemotherapy reported problems with memory and concentration.
Still, the cause of chemo brain has been difficult to pinpoint, leading some doctors to doubt its existence. Some studies using magnetic resonance imaging (MRI) have found small changes in brain volume after chemotherapy, but no definitive link has been found.
So Lagos and colleagues took a different tactic, using a combination of PET and CT imaging to look for changes in brain metabolism in 128 patients who had undergone chemotherapy for breast cancer.
"PET/CT imaging shows how the brain is using energy. So it gives you an earlier look at regions of the brain that are being affected by chemotherapy, as they start to use less energy. That happens long before you can see structural changes in the brain on MRI," she says.
PET/CT imaging revealed changes in metabolism in brain regions involved in long-term memory, mental agility, decision making, problem solving, and prioritizing.
The findings were presented here at the annual meeting of the Radiological Society of North America.
Chemo Brain: Outside Perspective
"Importantly, the regions of the brain that were affected made sense in terms of the symptoms that patients report," says Max Wintermark, MD, engineering chief of neuroradiology for the University of Virginia.
"They have difficulty remembering things and carrying out simple daily tasks such as planning the week's meals," he says. Wintermark was not involved in the study, but moderated a news briefing to discuss its findings.
The results may be reassuring for women who experience chemo brain, Wintermark says.
"Just being able to show something is going on in the brain lets patients know they are not inventing the symptoms. That will help them go through this horrible experience," he says.
The good news: Chemo brain tends to get better on its own once chemotherapy is finished, Lagos says. She came to that conclusion after comparing imaging scans taken during treatment and after it was completed.
And in the meantime? Having family members or friends help you make lists and plan can help you get through the period of mental fog, Lagos says.
While the researchers only studied breast cancer patients, chemo brain has been reported in patients undergoing chemotherapy for other cancers as well.
These findings were presented at a medical conference. They should be considered preliminary, as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.
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