Breast cancer patients have reported nonspecific neurologic symptoms such as fatigue, depression, and cognitive concerns while undergoing adjuvant therapy. Few neuroimaging studies have examined hormone therapy, an adjuvant therapy, and more research is needed to determine possible neurologic and cognitive effects. Previous estrogen research has found alterations in gray matter volume and cortical thickness. The nature of the neurological and cognitive effect of hormone therapy as an adjuvant therapy for breast cancer is unclear due to sparse and conflicting literature. Based on the widespread effects of estrogen in the brain, we expect there to be structural differences in patients who have undergone hormone therapy in comparison to healthy controls. Structural and functional MRI were acquired from a sample of breast cancer patients who were undergoing hormone therapy at the time of the study, but who had not received chemotherapy, and a sample of healthy age-matched controls without a history of cancer. Resting-state functional connectivity (rsFC) was calculated between brain regions. Fractional amplitude of low frequency fluctuations (fALFF) was computed within a rsFC-derived mask to describe the regional properties within sites of dysconnectivity. Objective measures of cognition were obtained using neuropsychological tests and correlated with rsFC. Cortical thickness was calculated with a 10 mm smoothing kernel, using ComBat harmonization for scanner effects, and correcting for multiple comparisons with a Monte Carlo simulation. A priori analyses did not yield any significant findings that survived multiple comparison correction. Following this, a series of ad hoc analyses were conducted using two additional cortical metrics, four methods of data harmonization, six smoothing kernels, and two methods of multiple comparison correction. Patients demonstrated extensive dysconnectivity relative to controls, largely characterized by parietal-occipital hypoconnectivity. Reduced rsFC occurred primarily between regions with increased fALFF. A modest relationship between rsFC and visual working memory was observed in breast cancer patients but not in controls. Differences in cortical structure were far subtler in comparison. This study is the first to examine whole-brain rsFC, fALFF, and vertex-wise measures of cortical structure in breast cancer patients undergoing hormone therapy. We found robust hypoconnectivity in patients, which demonstrated modest relationships with cognition. Cortical structure remained largely preserved. Identifying the pattern by which breast cancer and hormone therapy affect brain networks may aid in the development of therapeutic options for patients experiencing negative effects of hormone therapy, thus improving quality of life for cancer survivors. Further, the detection of abnormal brain function may allow for the identification of treatment-associated decline prior to the emergence of cognitive impairment in patients.

Creator

• Petersen, Julie

DOI

• https://doi.org/10.21985/n2-5jmv-dy22

Subject

• Cognitive psychology
• Clinical psychology
• Neurosciences

Language

• en

Alternate Identifier

• etdadmin_upload_1015189
• http://dissertations.umi.com/northwestern:16790

Keyword

• Breast cancer
• Neuroimaging
• Cancer treatment
• Neuropsychology

Date created

• 2023-01-01

Resource type

• Dissertation

Rights statement

• In Copyright