Psychological Processes and Symptom Outcomes in Mindfulness-Based Stress Reduction for Cancer Survivors: A Pilot Study.

Objectives: Growing evidence supports the efficacy of mindfulness-based interventions for symptoms in cancer survivors. Identifying theory-based psychological processes underlying their effects on symptoms would inform research to enhance their efficacy and cost-effectiveness. We conducted secondary analyses examining the effect of mindfulness-based stress reduction (MBSR) for cancer-related fatigue on mindfulness facets, self-compassion, and psychological inflexibility. We also examined whether changes in these processes were associated with the symptom outcomes of fatigue interference, sleep disturbance, and emotional distress.

Methods: Thirty-five persistently fatigued cancer survivors (94% female, 77% breast cancer survivors) were randomized to either MBSR for cancer-related fatigue or a waitlist control (WC) condition. Self-report measures were administered at pre-intervention, post-intervention, and 1-month follow-up. Then the WC group received MBSR and completed a post-intervention follow-up.

Results: Linear mixed modeling analyses of the first three time points showed steady increases over time for certain mindfulness facets (observing, acting with awareness, and nonjudging) and self-compassion in favor of the MBSR group. When analyzing pre- and post-intervention data across study conditions, none of the psychological processes predicted change in fatigue interference. However, increased nonjudging was associated with decreased sleep disturbance (β = -.39, p = .003), and increased acting with awareness was associated with decreased emotional distress (β = -.36, p = .003). Self-compassion did not predict change in symptom outcomes.

Conclusions: Results point to specific psychological processes that may be targeted to maximize the efficacy of future MBSR interventions for cancer survivors.