Chemo damage

Chemotherapy not only causes the phenomenon called “chemobrain,” there now is evidence of subtle changes in specific brain regions explaining why some patients can’t remember where they’ve placed their keys or lose their way along well traveled routes.

Chemotherapy not only causes the phenomenon called “chemobrain,” there now is evidence of subtle changes in specific brain regions explaining why some patients can’t remember where they’ve placed their keys or lose their way along well traveled routes.

Despite a few past studies suggesting chemobrain—a feeling reported by cancer patients of forgetfulness, confusion and disorientation—was more imagined than real, a team of medical investigators in Japan found the condition indeed is genuine and substantially affects cognition. Reported in the current issue of Cancer, the analysis provides concrete evidence that chemotherapy affects regions involved in thinking, reasoning and remembering.

“Prevention is not right around the corner” and remains years down the road, said Dr Stewart Fleishman, director of cancer supportive services at Beth Israel and St. Luke’s-Roosevelt medical centers in Manhattan. “But now we can tell patients and their families what to expect,” Fleishman said.

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Dr. Masatoshi Inagaki of Japan’s National Cancer Center Hospital explored specific brain regions through magnetic resonance imaging. He compared two groups: those who underwent chemo and those who did not.

Chemobrain has been reported among patients who have undergone chemotherapy for virtually all forms of cancer but has been a particular complaint among breast cancer patients. Some studies have suggested that up to 40 percent of women who undergo chemotherapy for breast cancer are affected by cognitive problems.

Some doctors have suggested that chemotherapy might alter the effects on hormones on the brain, which in turn has an effect on cognition. Not until now had a team produced evidence of specifically affected brain sites.

Inagaki observed in the 51 women who underwent chemo, there were dramatically smaller volumes of brain tissue in specific sites one year after treatment compared with the 54 patients who were not exposed to the drugs. Brain sites most affected included the prefrontal lobe, parahippocampal, cingulate gyrus and precuneus regions. Each is intimately involved in cognition.

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Yet three years later, there were no significant differences in tissue volume between the two groups of patients, suggesting the brain is capable of bouncing back.

Dr. Arnold Baskies of the American Cancer Society’s Eastern Division said the study proves what patients have reported anecdotally for years: Chemobrain is real. “This is a very interesting study because of the way it was done,’’ Baskies said. “It was a controlled study of patients who had the same disease and either received chemo or didn’t receive chemo. It demonstrated something that many of us suspected for some time, that chemobrain does exist.”

He said the powerful drugs used to fight cancer are capable of diffusing through the blood-brain barrier, a protective sheath that keeps most harmful substances out of the brain. Many chemo drugs are made up of molecules small enough to breach the barrier.

—Newsday / Delthia Ricks