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Scholarly Works (7 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2021)

Background: Younger breast cancer survivors (YBCS) consistently report poorer quality of life (QOL) than older survivors. One potential strategy to improve QOL is through increasing physical activity (PA), but this has been understudied in YBCS. YBCS face unique barriers to PA related to treatment side effects and life stage.

Purpose: This dissertation leveraged a community-academic partnership to evaluate the feasibility, acceptability, and implementation of a 3-month, peer-delivered, fully remote intervention to increase PA and improve QOL in YBCS.

Methods: Participants completed six video sessions with a trained YBCS peer mentor; self-monitored PA with a Fitbit activity tracker; and interacted with a private Fitbit Community for social support. At baseline, 3, and 6-months, participants completed validated QOL questionnaires and PA was measured through accelerometer (objective moderate-to-vigorous PA [MVPA]) and self-report (strength and flexibility). A parallel mixed methods approach (qualitative interviews and quantitative satisfaction survey) explored feasibility and acceptability. One-way repeated-measures ANOVA examined impacts on PA and QOL at 3-and 6-months. A multimethod process evaluation explored peer mentors’ barriers and facilitators to intervention delivery and adaptations.

Results: On average, participants (N=34) were 43.1±5.5 years old, 46±34.4 months post-diagnosis, and self-reported a BMI of 30.2±7.4 kg/m2. The intervention was feasible as evidenced by efficient recruitment, high retention, and adherence to intervention components. Remote delivery was highly acceptable, as were working with a peer mentor and using the suite of Fitbit tools to support behavior change. From baseline to 3-months, participants increased time spent in objectively-measured MVPA, strength, and flexibility exercises, and experienced meaningful improvements to QOL, including body image, fatigue, anxiety, and emotional support. Adaptations to enhance feasibility of study protocols and engagement in the Fitbit Community occurred throughout intervention delivery. Prominent barriers and facilitators to effective delivery were related to communication, preparation and training, complexity of technology, and life circumstances.

Conclusions: A fully remote, peer-to-peer, technology-based intervention is an acceptable and promising strategy to increase PA and improve QOL in YBCS. Refinements to the intervention and its implementation should be assessed in a fully-powered hybrid effectiveness-implementation trial, toward the goal of disseminating an evidence-based, scalable intervention to the growing number of YBCS.

    Cover page: A Remotely Delivered, Peer-Led Intervention to Improve Physical Activity and Quality of Life in Younger Breast Cancer Survivors
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2019)
    PURPOSE: Cancer survivors are highly sedentary and have low physical activity. How physical activity interventions impact sedentary behavior remains unclear. This secondary analysis examined changes in sedentary behavior among breast cancer survivors participating in a physical activity intervention that significantly increased moderate-to-vigorous physical activity (MVPA). METHODS: Insufficiently active breast cancer survivors were randomized to a 12-week physical activity intervention (exercise arm) or control arm. The intervention focused solely on increasing MVPA with no content targeting sedentary behavior. Total sedentary behavior, light physical activity (LPA), and MVPA were measured at baseline and 12 weeks (ActiGraph GT3X+ accelerometer). Separate linear mixed-effects models tested intervention effects on sedentary behavior, intervention effects on LPA, the relationship between change in MVPA and change in sedentary behavior, and potential moderators of intervention effects on sedentary behavior. RESULTS: The exercise arm had significantly greater reductions in sedentary behavior than the control arm (mean - 24.9 min/day (SD = 5.9) vs. - 4.8 min/day (SD = 5.9), b = - 20.1 (SE = 8.4), p = 0.02). Larger increases in MVPA were associated with larger decreases in sedentary behavior (b = - 1.9 (SE = 0.21), p < 0.001). Women farther out from surgery had significantly greater reductions in sedentary behavior than women closer to surgery (b = - 0.91 (SE = 0.5), p = 0.07). There was no significant group difference in change in LPA from baseline to 12 weeks (b = 5.64 (SE = 7.69), p = 0.48). CONCLUSIONS: Breast cancer survivors in a physical activity intervention reduced total sedentary time in addition to increasing MVPA. IMPLICATIONS FOR CANCER SURVIVORS: Both increasing physical activity and reducing sedentary behavior are needed to promote optimal health in cancer survivors. These results show that MVPA and sedentary behavior could be successfully targeted together, particularly among longer-term cancer survivors. CLINICAL TRIAL REGISTRATION: This study is registered at www.ClinicalTrials.gov (NCT02332876).
      Cover page: Breast cancer survivors reduce accelerometer-measured sedentary time in an exercise intervention.
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2019)
      Breast cancer is the most common cancer of women in the United States. It is also proving to be one of the most treatable. Early detection, surgical intervention, therapeutic radiation, cytotoxic chemotherapies and molecularly targeted agents are transforming the lives of patients with breast cancer, markedly improving their survival. Although current breast cancer treatments are largely successful in producing cancer remission and extending lifespan, there is concern that these treatments may have long lasting detrimental effects on cancer survivors, in part, through their impact on non-tumor cells. Presently, the impact of breast cancer treatment on normal cells, its impact on cellular function and its effect on the overall function of the individual are incompletely understood. In particular, it is unclear whether breast cancer and/or its treatments are associated with an accelerated aging phenotype. In this review, we consider breast cancer survivorship from the perspective of accelerated aging, and discuss the evidence suggesting that women treated for breast cancer may suffer from an increased rate of physical and cognitive decline that likely corresponds with underlying vulnerabilities of genome instability, epigenetic changes, and cellular senescence.
        Cover page: Breast cancer treatment and its effects on aging
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2019)

        Purpose

        Cancer survivors are highly sedentary and have low physical activity. How physical activity interventions impact sedentary behavior remains unclear. This secondary analysis examined changes in sedentary behavior among breast cancer survivors participating in a physical activity intervention that significantly increased moderate-to-vigorous physical activity (MVPA).

        Methods

        Insufficiently active breast cancer survivors were randomized to a 12-week physical activity intervention (exercise arm) or control arm. The intervention focused solely on increasing MVPA with no content targeting sedentary behavior. Total sedentary behavior, light physical activity (LPA), and MVPA were measured at baseline and 12 weeks (ActiGraph GT3X+ accelerometer). Separate linear mixed-effects models tested intervention effects on sedentary behavior, intervention effects on LPA, the relationship between change in MVPA and change in sedentary behavior, and potential moderators of intervention effects on sedentary behavior.

        Results

        The exercise arm had significantly greater reductions in sedentary behavior than the control arm (mean - 24.9 min/day (SD = 5.9) vs. - 4.8 min/day (SD = 5.9), b = - 20.1 (SE = 8.4), p = 0.02). Larger increases in MVPA were associated with larger decreases in sedentary behavior (b = - 1.9 (SE = 0.21), p < 0.001). Women farther out from surgery had significantly greater reductions in sedentary behavior than women closer to surgery (b = - 0.91 (SE = 0.5), p = 0.07). There was no significant group difference in change in LPA from baseline to 12 weeks (b = 5.64 (SE = 7.69), p = 0.48).

        Conclusions

        Breast cancer survivors in a physical activity intervention reduced total sedentary time in addition to increasing MVPA.

        Implications for cancer survivors

        Both increasing physical activity and reducing sedentary behavior are needed to promote optimal health in cancer survivors. These results show that MVPA and sedentary behavior could be successfully targeted together, particularly among longer-term cancer survivors.

        Clinical trial registration

        This study is registered at www.ClinicalTrials.gov (NCT02332876).
          • Article
          • Peer Reviewed
          UC San Diego Previously Published Works (2018)

          Background

          Increasing physical activity can improve cognition in healthy and cognitively impaired adults; however, the benefits for cancer survivors are unknown. The current study examined a 12-week physical activity intervention, compared with a control condition, on objective and self-reported cognition among breast cancer survivors.

          Methods

          Sedentary breast cancer survivors were randomized to an exercise arm (n = 43) or a control arm (n = 44). At baseline and at 12 weeks, objective cognition was measured with the National Institutes of Health Cognitive Toolbox, and self-reported cognition using the Patient-Reported Outcomes Measurement Information System scales. Linear mixed-effects regression models tested intervention effects for changes in cognition scores.

          Results

          On average, participants (n = 87) were aged 57 years (standard deviation, 10.4 years) and were 2.5 years (standard deviation, 1.3 years) post surgery. Scores on the Oral Symbol Digit subscale (a measure of processing speed) evidenced differential improvement in the exercise arm versus the control arm (b = 2.01; P < .05). The between-group differences in improvement on self-reported cognition were not statistically significant but were suggestive of potential group differences. Time since surgery moderated the correlation, and participants who were ≤2 years post surgery had a significantly greater improvement in Oral Symbol Digit score (exercise vs control (b = 4.00; P < .01), but no significant improvement was observed in patients who were >2 years postsurgery (b = -1.19; P = .40). A significant dose response was observed with greater increased physical activity associated with objective and self-reported cognition in the exercise arm.

          Conclusions

          The exercise intervention significantly improved processing speed, but only among those who had been diagnosed with breast cancer within the past 2 years. Slowed processing speed can have substantial implications for independent functioning, supporting the potential importance of early implementation of an exercise intervention among patients with breast cancer. Cancer 2018;124:192-202. © 2017 American Cancer Society.
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2019)

            Background

            Emerging research suggests that increasing physical activity can help improve cognition among breast cancer survivors. However, little is known about the mechanism through which physical activity impacts cancer survivors' cognition.

            Objective

            The objective of this secondary analysis examined physical and psychological function potentially linking physical activity with changes in cognition among breast cancer survivors in a randomized controlled trial where the exercise arm had greater improvements in cognition than the control arm.

            Methods

            A total of 87 sedentary breast cancer survivors were randomized to a 12-week physical activity intervention (n=43) or control condition (n=44). Objectively measured processing speed (National Institutes of Health Toolbox Oral Symbol Digit), self-reported cognition (patient-reported outcomes measurement information system [PROMIS] cognitive abilities), PROMIS measures of physical and psychological function (depression, anxiety, fatigue, and physical functioning), and plasma biomarkers (brain-derived neurotrophic factor, homeostatic model assessment 2 of insulin resistance, and C-reactive protein [CRP]) were collected at baseline and 12 weeks. Linear mixed-effects models tested intervention effects on changes in physical and psychological function variables and biomarkers. Bootstrapping was used to assess mediation. Exploratory analyses examined self-reported cognitive abilities and processing speed as mediators of the intervention effect on physical functioning.

            Results

            Participants in the exercise arm had significantly greater improvements in physical functioning (beta=1.23; 95% CI 2.42 to 0.03; P=.049) and reductions in anxiety (beta=-1.50; 95% CI -0.07 to -2.94; P=.04) than those in the control arm. Anxiety significantly mediated the intervention effect on cognitive abilities (bootstrap 95% CI -1.96 to -0.06), whereas physical functioning did not (bootstrap 95% CI -1.12 to 0.10). Neither anxiety (bootstrap 95% CI -1.18 to 0.74) nor physical functioning (bootstrap 95% CI -2.34 to 0.15) mediated the intervention effect on processing speed. Of the biomarkers, only CRP had greater changes in the exercise arm than the control arm (beta=.253; 95% CI -0.04 to 0.57; P=.09), but CRP was not associated with cognition; therefore, none of the biomarker measures mediated the intervention effect on cognition. Neither cognitive abilities (bootstrap 95% CI -0.06 to 0.68) nor processing speed (bootstrap 95% CI -0.15 to 0.63) mediated the intervention effect on physical function.

            Conclusions

            Physical activity interventions may improve self-reported cognition by decreasing anxiety. If supported by larger studies, reducing anxiety may be an important target for improving self-reported cognition among cancer survivors.

            Trial registration

            ClinicalTrials.gov NCT02332876; https://clinicaltrials.gov/ct2/show/NCT02332876.
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2021)

              Introduction

              Difficulties with cognition are extremely common among breast cancer survivors and can significantly impact quality of life, daily functioning, and ability to return to work. One promising intervention is increasing physical activity, as it has been effective in improving cognition in non-cancer populations. Few physical activity intervention trials with cognition outcomes have included cancer survivors. This project builds upon our previous work indicating that increased physical activity can improve objectively measured processing speed and self-reported cognition among breast cancer survivors.

              Methods

              The I Can! study will examine whether a physical activity intervention improves cognition among 250 post-treatment breast cancer survivors (Stages I-III, <5 years post-treatment) who are reporting cognitive difficulties. This 2-arm randomized controlled trial comparing a 6-month physical activity intervention (Exercise Group) to a health & wellness attention-comparison condition (Health & Wellness Group) will examine intervention effects on cognition (at 3 and 6 months) and maintenance of effects at 12 months. The primary aim is to investigate the impact of exercise on objectively measured processing speed and self-reported cognition. Secondary aims are to investigate maintenance of cognitive changes and examine candidate biological mechanisms and psychological mediators.

              Conclusion

              The I Can! study will contribute to the scientific, public health, and survivorship intervention literature by providing new information on the impact of physical activity for cognitive impairment in breast cancer survivors. Findings from this study will inform guidelines for physical activity to improve the lives of millions of breast cancer survivors.
                Cover page: A randomized trial of physical activity for cognitive functioning in breast cancer survivors: Rationale and study design of I Can! Improving Cognition After Cancer
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