Cognitive Dysfunction in Older Breast Cancer Survivors

Abstract

Up to 75% of the more than 3.5 million breast cancer survivors (BCS) living in the United States report cognitive dysfunction. However, little is known about cognitive dysfunction among older BCS, who may be at greater risk. Therefore, the purpose of this dissertation was to characterize cognitive dysfunction in older BCS. Specific aims included: (1) synthesize the literature regarding cognitive dysfunction in older BCS; and (2) examine the relationships between a) objective cognitive function (immediate memory, delayed memory, attention, executive function-working memory, verbal fluency) and subjective cognitive function (attention); b) demographic factors, medical factors, treatment factors, and cancer-related symptoms (depressive symptoms, anxiety, fatigue, sleep disturbance) and cognitive function; and c) comorbidity and cognitive function and physical functioning, and quality of life (QoL) in older BCS. In an integrative review, to address aim 1, 12 studies were identified. Up to 41% of older BCS showed objective cognitive dysfunction on neuropsychological assessment, up to 64% reported subjective cognitive dysfunction concerns pre-treatment, and 50% incurred cognitive decline from pre- to post-treatment. Cognitive dysfunction was associated with older age, multiple comorbidities, chemotherapy, sleep disturbance, neuropsychological symptom cluster, frailty, and poorer QoL. To address aim 2, data were leveraged from a large, nationwide, QoL in younger versus older BCS study (PI: Champion), which included 335 older BCS who were ≥60 years of age, had breast cancer (stage I-IIIa), received chemotherapy, and were 3-8 years post-diagnosis without recurrence. Findings included up to 19% of older BCS had mild-moderate objective cognitive dysfunction on at least one neuropsychological assessment, with 26% reporting poor-moderate subjective attention function. BCS, who were older, had less education and more depressive symptoms had greater cognitive dysfunction. Objective attention and executive function-working memory significantly and positively correlated with subjective attention. In turn, subjective cognitive dysfunction and increased number of comorbidities were related to poorer physical functioning. Subjective cognitive dysfunction was also related to poorer QoL. The findings from this study highlights the prevalence and complexity of cognitive dysfunction in older BCS. Further research is needed to better understand the intersection of aging, cancer, comorbidities and cognitive dysfunction and the negative implications in older BCS.