Mindfulness-Based Stress Reduction in Post-Treatment Breast Cancer Patients: Immediate and Sustained Effects across Multiple Symptom Clusters.

Breast cancer survivors (BCS) face adverse physical and psychological symptoms, often co-occurring. Biological 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.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.322 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 (QOL) 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.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.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.