Aromatase inhibitor treatment is associated with metabolic changes in the brain

This paper studied the effect of aromatase inhibitors on cognitive function of older patients with breast cancer. 

Aromatase inhibitors are drugs that block the activity of estrogen receptors (proteins on cells that react to the presence of the hormone estrogen). Not only do estrogen receptors promote cell growth and division, they also promote the growth of neurons, cells involved in brain function. Hence, it was suggested that aromatase inhibitors could influence brain function. 

32 patients and 35 healthy participants (to be used as comparison) aged 60 and older were analysed. Patients completed various tests before and after aromatase inhibitor therapy. Healthy participants also completed the same assessments at similar times. 

Functional status (ability to take care of oneself) was higher in healthy participants than breast cancer patients at both the start of study and during follow-up. With regards to neuropsychological assessment (examination of impairment to certain skills, which can identify areas of the brain that are damaged), certain aspects of function improved from start of study to follow-up in breast cancer patients.  At follow-up, patients reported better memory function on a self-rating questionnaire.

PET imaging (positron emission tomography; a scan which measures changes inchemical processess that occur in the brain to provide energy for the brain) found changes at 4 parts of the brain between the start of study and follow-up in patients who underwent aromatase inhibitor therapy. In addition, a region in the brain involved with language showed decreased metabolism after aromatase therapy. These changes did not occur in the healthy participants. 

The authors concluded that there were no significant effects on neuropsychological performance. However, there was changes in metabolic activity of the brain between the start of study and follow-up in patients who received aromatase inhibitors. Studies with longer follow-up are required to assess the implications of this finding. 

PET scans were only performed on a small portion of participants (10 breast cancer patients and 10 healthy participants).