A Prospective Neuroimaging Study of Chemotherapy-Related Cognitive Impairment in Breast Cancer Patients

Abstract

Complaints of reduced cognitive abilities are frequent following chemotherapy. Research in the breast cancer population has revealed some patients may experience treatment-related decline in cognitive domains such as executive function, information processing speed, memory and learning, attention and concentration, and working memory. The extent and mechanism of action of this phenomenon remain poorly understood. Neuroimaging research can characterize the neural underpinnings of chemotherapy-related cognitive impairment; however, with few longitudinal studies, more prospective studies are needed to elucidate this important topic. The aim of this thesis was to use magnetic resonance imaging and contemporary analysis techniques to better understand the influence chemotherapy exerts on both the brain and cognition. This was achieved in two studies that measured cognitive function and brain structure and function at three time points: pre-treatment, one month post-chemotherapy, and at one-year follow-up. In the first study, the association between regions of brain structural changes and cognitive function was examined. The second study took a narrower approach and investigated the functional profile of brain activity during a working memory task. Patients had more pronounced structural and functional disruptions shortly after treatment, relative to both pre-treatment and one-year post-chemotherapy intervals. Regions of structural compromise were largely associated with information processing speed. Functional disruptions occurred in a frontoparietal network. Overall, this thesis provides more evidence of the injurious role chemotherapy plays on cognition, particularly in the short term. This thesis also provides the first longitudinal neuroimaging study to illustrate a complete resolution of working memory related brain disruption one year post-treatment.