Effects of Chemotherapy on Neural Processes During Cognitive Functioning in Early-Stage Breast Cancer Patients: An fMRI Study

Abstract

Functional Magnetic Resonance Imaging (fMRI) was used to examine brain activity in women with early stage Breast Cancer (BC) and to compare their neural profiles to a matched control group. This was accomplished as participants performed two working memory tasks, before and at two time points following the chemotherapy intervention of the BC group. Nineteen BC patients between the ages of 18 and 65 years were recruited from the Ottawa Hospital Regional Cancer Centre. The nineteen control participants were matched on sex, language, age and education. The results, from whole brain analyses, show significant differences in neural activity between BC patients and matched control participants during both verbal and visuospatial working memory tasks, before and right after chemotherapy. However, these differences were no longer observed one year post chemotherapy for verbal WM processing. Performance results were not significantly different between groups until the third imaging sessions when patients made significantly more errors of omission than controls for both tasks. Importantly, mood, anxiety and fatigue all played significant roles in the observed findings demonstrating the multifaceted nature of the impact of both cancer and chemotherapy on neural function during working memory. This is one of the first fMRI studies to measure neural activations during cognitive performance both before and after chemotherapy in BC patients and a control group while controlling for many potentially confounding variables. While BC patients should be made aware of the potential cognitive challenges they might face before, during and shortly after treatment, they can also feel reassured that these impairments may not be long lasting.