Patients with breast cancer have quantifiable declines in cognitive function compared with age-matched controls, and this chemotherapy-related cognitive decline correlates with molecular immune biomarkers, genetic aging, and neurotransmitter markers. These study results were presented at the 2015 American Society for Clinical Oncology Annual Meeting in Chicago, IL.
Up to 80% of patients experience chemotherapy-related cognitive impairment (CRCI) during therapy, along with 35% of patients after treatment.1 Common problem areas include executive function, memory, concentration, attention, verbal fluency, and processing speed. This negatively impacts quality of life and performance at work, explained the presenter, Michelle C. Janelsins, PhD, MPH, of Wilmot Cancer Institute and the University of Rochester Medical Center in Rochester, New York. The causes of CRCI are likely multifactorial and may include clinical, demographic, psychological, and biological factors.
The primary aim of the study was to quantify the difference in cognitive function in patients with breast cancer from prechemotherapy to postchemotherapy compared with a control comparison group of the same age and gender.
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The patients who enrolled had invasive, nonmetastatic breast cancer of stage 1-3c, were chemotherapy-naïve and were scheduled to begin chemotherapy, and were 21 years old or older. The patients and the control individuals could not have any history of psychiatric illness, any neurodegenerative disease or primary central nervous system disease or disorder, and they could not be receiving concurrent radiation during chemotherapy.
The patients were assessed by neuropsychological assessments, self-reports, and blood collections. The study enrolled 366 women with breast cancer and age-matched them with 366 healthy control women. The patients and control group were well matched in terms of age, race, and education level.
Chemotherapy is known to cause increases in cytokines and chemokines, which affect the blood-brain barrier. These may negatively impact cognitive function. So, in the blood, the study examined these inflammation-related biomarkers: monocyte chemoattractant protein one (MCP-1), the cytokine interleukin-one-beta (IL-1β), and soluble tumor necrosis factor receptor 1 (sTNFR1). The genes for catechol-o-methyltransferase (COMT), related to neurotransmitter signaling, and forkhead box protein O3 (FOXO3), related to aging, were also examined.
Neuropsychological testing found that, on all measures, the patients with breast cancer performed worse than the control individuals without cancer (P<0.01 for all measures). Also, patients with breast cancer had declines in cognitive function from the prechemotherapy to postchemotherapy period, while the control individuals had improvements.