Gray and white matter shrinkage could explain 'chemobrain'
Cognitive impairments noted in breast cancer survivors treated with adjuvant chemotherapy could be a result of a temporary reduction in the volume of gray and white matter in the brain, researchers believe.
Analysis of magnetic resonance images revealed smaller volumes of gray and white matter in the prefrontal, parahippocampal, and cingulate gyrus, as well as the precuneus in patients who underwent adjuvant chemotherapy, compared with those who did not, within a year of treatment, but the difference was lost after 3 or more years.
"Results lead to the idea that adjuvant chemotherapy could have a temporary effect on brain structure," the team, led by Yosuke Uchitomi, from Research Center for Innovative Oncology in Chiba, Japan.
Impairments in cognitive function have recently been recognized as a possible adverse effect of adjuvant chemotherapy, giving rise to the term "chemobrain," the researchers explain. But while the link has been shown in most studies, the neural mechanisms have not been fully explored.
A previous study that reported regional brain volumes in breast and lymphoma cancer survivors suggested that chemotherapy may reduce regional brain volume, but it failed to control for the effects of a cancer diagnosis.
Now, Uchitomi et al report in the journal Cancer that multiple regions of gray and white matter were significantly smaller in 51 breast cancer survivors who underwent cyclophosphamide, methotrexate, and 5-fluorouracil chemotherapy than in 55 not exposed to adjuvant chemotherapy within a year of surgery.
A parallel study of 73 patients given adjuvant chemotherapy and 59 control patients 3 or more years after surgery for breast cancer revealed no significant differences in brain volumes.
A comparison of MRI scans from both the 1- and 3-year studies with scans from healthy controls also revealed no significant differences in regional brain volumes, supporting the idea "that cancer had little influence on the main analyses of the current study," the team claims.
"These findings can provide new insights for future research to improve the quality of life of cancer patients who receive adjuvant chemotherapy," the researchers conclude.
Cancer 2007; 109: 146-156
http://www3.interscience.wiley.com/c...89209/ABSTRACT
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