PURPOSE: The term "chemobrain" is sometimes used to denote deficits in 
neuropsychological functioning that may occur as a result of cancer treatment. 
As breast cancer survivors now commonly reach late life, it is not known whether 
previous exposure to chemotherapy may affect long-term risk for cognitive 
impairment. To help address this concern, this study tested whether successfully 
surviving chemotherapy earlier in life was associated with later differences in 
brain metabolic function as an older adult compared to controls. This question 
was examined using positron emission tomography measures of brain glucose 
metabolism in elderly women cancer survivors.
METHODS: Breast cancer survivors (N = 10), currently free of recurrent cancer 
and without a diagnosis of a cognitive disorder, were compared to matched 
healthy controls (N = 10). All subjects were imaged at rest with 
[(18)F]fluorodeoxyglucose. Images were analyzed semi-quantitatively using the 
Alzheimer's Discrimination Tool and a volume of interest-based approach derived 
from co-registered magnetic resonance imaging.
RESULTS: Relative [(18)F]fluorodeoxyglucose uptake (normalized to global) was 
significantly lower in the survivors compared with control subjects in bilateral 
orbital frontal regions, consistent with differences between the groups in 
cognition and executive function (i.e., Trail Making Test, Part B and 
mini-mental state examination) and despite no significant differences with 
respect to age, education, intelligence, or working memory. None of the 
survivors and only one control manifested a global positron emission tomography 
score consistent with an Alzheimer's disease metabolic pattern.
CONCLUSION: Breast cancer survivors treated with chemotherapy may manifest 
long-term changes in brain glucose metabolism indicative of subtle frontal 
hypometabolism, a finding consistent with results from neuropsychological 
testing and other imaging modalities.