Randomized Controlled Pilot Trial of Mindfulness-based Stress Reduction for Breast and Colorectal Cancer Survivors: Effects on Cancer-related Cognitive Impairment

Purpose: Cancer-related cognitive impairment (CRCI) is a common, fatigue-related symptom that disrupts cancer survivors' quality of life. Few interventions for CRCI exist. As part of a randomized pilot study targeting cancer-related fatigue, the effects of mindfulness-based stress reduction (MBSR) on survivors' cognitive outcomes were investigated.

Methods: Breast and colorectal cancer survivors (n = 71) with moderate-to-severe fatigue were randomized to MBSR (n = 35) or a fatigue education and support (ES; n = 36) condition. The Attentional Function Index (AFI) and the Stroop test were used to assess survivors' cognitive function at baseline (T1), after the 8-week intervention period (T2), and 6 months later (T3) using intent-to-treat analysis. Mediation analyses were performed to explore mechanisms of intervention effects on cognitive functioning.

Results: MBSR participants reported significantly greater improvement on the AFI total score compared to ES participants at T2 (d = 0.83, p = 0.001) and T3 (d = 0.55, p = 0.021). MBSR also significantly outperformed ES on most AFI subscales, although both groups improved over time. MBSR produced greater Stroop accuracy rates relative to ES at T2 (r = 0.340, p = 0.005) and T3 (r = 0.280, p = 0.030), with improved accuracy over time only for the MBSR group. There were no significant differences in Stroop reaction time between groups. Improvements in mindfulness mediated the effect of group (e.g., MBSR vs. ES) on AFI total score at T2 and T3.

Conclusions: Additional randomized trials with more comprehensive cognitive measures are warranted to definitively assess the efficacy of MBSR for CRCI.

Implications For Cancer Survivors: This pilot study has important implications for all cancer survivors as it is the first published trial to show that MBSR offers robust and durable improvements in CRCI.