Date

9-15-2015

Document Type

Dissertation

Degree Name

Ph.D.

Institution

Oregon Health & Science University

Abstract

Background: Symptom cluster research in cancer has linked reports of cognitive problems, depression, and fatigue, along with sleep disturbance, anxiety, and pain in a psychoneurologic symptom cluster, potentially with a shared underlying inflammatory cytokine mechanism. Better understanding of the levels and trajectories of attentional function, depression, and fatigue and the relationships among these variables is needed to pursue knowledge of underlying mechanisms and to develop interventions targeted at helping to manage cancer-related symptoms. The purpose of the study was to describe how levels of attentional function, fatigue, and depression change over time and whether levels and trajectories of fatigue and depression predict levels and trajectories of attentional function in women with breast cancer being treated with chemotherapy.

Methods: This study is a secondary analysis of data from two prospective longitudinal studies of women with early stage breast cancer (Stage I – III) being treated with chemotherapy. Attentional function was measured with the Attentional Function Index (AFI), depression with Center for Epidemiologic Studies – Depression (CESD), and fatigue with two instruments: Patient-Reported Outcomes Measurement Information System – Fatigue (PROMIS) and the Schwartz Cancer Fatigue Scale (SCFS). Sample 1 (N = 24) was from the NW U.S. and Sample 2 (N = 44) was from the NE U.S. Study data was collected at clinically significant measurement times: before the first day of chemotherapy, at mid-treatment, at the end of treatment with chemotherapy and 3 to 6 months after the end of treatment with chemotherapy. Depending on chemotherapy regimens, participants were in the study for 9 to 12 months. Assessments were timed to be just prior to a dose of chemotherapy to control for confounding medication effects. Attentional function was the primary outcome variable. Longitudinal multilevel modeling was used to accommodate exploration of time-varying covariates in a model with a time-varying primary outcome variable.

Results: Most of the participants were in their early 50s, non-Hispanic Caucasian, and married or partnered. Compared to the women in Sample 2, the women in Sample 1 were less likely to be employed full time (p < .001), more likely to have an income at or below U.S. median income (~$53,000) (p < .001), and more likely to have a high school education or less (p < .05). Sample 1 reported consistently worse levels of attentional function, depression, and fatigue across time. In a longitudinal multilevel model for attentional function, a fixed quadratic model fit the Sample 1 data better than a fixed linear model (χ2 (2) = 5.14, p = .0233). The model adding a random slope was nonconforming. In Sample 2, a fixed quadratic model provided the best fit to the data (χ2 (2) = 3.13, p = .0768) and the addition of a random slope did not improve the model fit (χ2 (2) = 2.06, p = .3474). Similarly, depression and fatigue were fit to fixed quadratic models. Adding depression as a time-varying covariate to a model with attentional function resulted in a significant coefficient for depression (Sample 1, β = -.76, SE = .19; z = -3.87, p < .001; and Sample 2, β = -.91, SE = .13; z = -6.96, p < .001).

Conclusions: These results suggest that the trajectories of attentional function, depression, and fatigue in a population of women with breast cancer receiving chemotherapy each exhibit a quadratic curve such that after start of chemotherapy each symptom worsens until mid-treatment and starts to improve before the end of treatment, returning to pretreatment levels by 3 to 6 months after the end of treatment. In a model with attentional function, the trajectory of fatigue predicts the trajectory of attentional function such that a worsening of fatigue predicts a worsening of attentional function. In a model with attentional function, the trajectory of depression predicts the trajectory of attentional function such that a worsening of depression predicts a worsening of attentional function. The science of symptom management, specifically of symptom cluster science, will benefit from this new knowledge related to trajectories of and relationships between attentional function, depression, and fatigue in women with breast cancer receiving treatment with chemotherapy. Author: Ginger Payne Keller Approved:

Identifier

doi:10.6083/M4WM1CCZ

School

School of Nursing

Included in

Nursing Commons

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