Chemotherapy causes brain shrinkage, study finds

A team of researchers led by Dr. Masatoshi Inagaki of the National Cancer Center Hospital East examined high-resolution MRI brain scans of breast cancer survivors treated with adjuvant chemotherapy taken one year after the patients' surgery. The researchers compared those scans to brain scans of adjuvant chemo patients taken three years after surgery, and to scans of healthy control patients.

The researchers found that the patients whose scans had been taken a year after surgery had smaller gray and white brain matter in areas of the brain that are involved in cognition and memory -- the prefrontal, parahippocampal, cingulated gyrus and precuneus regions -- compared to the control patients who had never undergone chemotherapy.

However, Inagaki found that the brain shrinkage seems to be reversible, since there was no difference in brain matter size between patients whose scans were taken three years after surgery and control patients.

"Results lead to the idea that adjuvant chemotherapy could have a temporary effect on brain structure," the researchers wrote. "These findings can provide new insights for future research to improve the quality of life of cancer patients who receive adjuvant chemotherapy."

The researchers did not study the effects of different chemotherapy agents on the brain because interactions between chemo drugs would have made definitive conclusions difficult. However, Inagaki and colleagues wrote that "these results indicate a potential effect of adjuvant chemotherapy on brain structure, and the change of the brain structure may be associated with memory function."

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