Mindfulness-Based Stress Reduction in Post-treatment Breast Cancer Patients: Immediate and Sustained Effects Across Multiple Symptom Clusters

Abstract

Context: Breast cancer survivors (BCS) face adverse physical and psychological symptoms, often co-occurring. Biologic and psychological factors may link symptoms within clusters, distinguishable by prevalence and/or severity. Few studies have examined the effects of behavioral interventions or treatment of symptom clusters.

Objectives: The aim of this study was to identify symptom clusters among post-treatment BCS and determine symptom cluster improvement following the Mindfulness-Based Stress Reduction for Breast Cancer (MBSR(BC)) program.

Methods: Three hundred twenty-two Stage 0-III post-treatment BCS were randomly assigned to either a six-week MBSR(BC) program or usual care. Psychological (depression, anxiety, stress, and fear of recurrence), physical (fatigue, pain, sleep, and drowsiness), and cognitive symptoms and quality of life were assessed at baseline, six, and 12 weeks, along with demographic and clinical history data at baseline. A three-step analytic process included the error-accounting models of factor analysis and structural equation modeling.

Results: Four symptom clusters emerged at baseline: pain, psychological, fatigue, and cognitive. From baseline to six weeks, the model demonstrated evidence of MBSR(BC) effectiveness in both the psychological (anxiety, depression, perceived stress and QOL, emotional well-being) (P = 0.007) and fatigue (fatigue, sleep, and drowsiness) (P < 0.001) clusters. Results between six and 12 weeks showed sustained effects, but further improvement was not observed.

Conclusion: Our results provide clinical effectiveness evidence that MBSR(BC) works to improve symptom clusters, particularly for psychological and fatigue symptom clusters, with the greatest improvement occurring during the six-week program with sustained effects for several weeks after MBSR(BC) training.

Trial registration: Name and URL of Registry: ClinicalTrials.gov. Registration number: NCT01177124.

Keywords: Breast cancer; Mindfulness-Based Stress Reduction (MBSR); physical symptoms; post-treatment; psychological symptoms; symptom cluster.

Copyright © 2016. Published by Elsevier Inc.

Figures

Fig. 1.

Baseline confirmatory factor analysis. Latent variables (clusters) are presented within circles. The measures that compose the clusters are presented in squares. Arrows and standardized beta weights indicate the linkages. All beta weights between measures and symptom clusters were statistically significant (P < 0.001).

Fig. 2.

Six-week structural equation model. Confirmatory factor analysis model is the same as baseline. The measured variables were quantified using difference squares between baseline and six weeks to control for initial levels. Experimental assignment is represented in the MBSR(BC) box. Arrows and standardized beta weights from this box represent MBSR(BC)’s relationship to symptom improvement: **P < 0.01; ***P = 0.001. All beta weights between measures and symptom clusters were statistically significant (P < 0.001). BPI = Brief Pain Inventory; CAMS-R = Cognitive and Affective Mindfulness Scale-Revised; CESD = Center for Epidemiological Studies Depression; ECog = Everyday Cognition; FSI = Fatigue Symptom Inventory; MBSR(BC) = Mindfulness-Based Stress Reduction for Breast Cancer; MDASI = M.D. Anderson Symptom Inventory; PSS = Perceived Stress Scale; PSQI = Pittsburgh Sleep Quality Index; SF-36 = Short-Form General Health Survey; STAI = State-Trait Anxiety Inventory.

Fig. 3.

Six- to 12-week structural equation model. Confirmatory factor analysis model is the same as baseline. The measured variables were quantified using difference scores from six weeks to 12 weeks to control for initial levels. Experimental assignment is represented in the MBSR(BC) box. Arrows and standardized beta weights from this box represent MBSR(BC)’s relationship to symptom improvement. All beta weights between measures and symptom clusters were statistically significant (P < 0.001). BPI = Brief Pain Inventory; CAMS-R = Cognitive and Affective Mindfulness Scale-Revised; CESD = Center for Epidemiological Studies Depression; ECog = Everyday Cognition; FSI = Fatigue Symptom Inventory; MBSR(BC) = Mindfulness-Based Stress Reduction for Breast Cancer; MDASI = M.D. Anderson Symptom Inventory; PSS = Perceived Stress Scale; PSQI = Pittsburgh Sleep Quality Index; SF-36 = Short-Form General Health Survey; STAI = State-Trait Anxiety Inventory.