Mindfulness based stress reduction (MBSR(BC)) in breast cancer: evaluating fear of recurrence (FOR) as a mediator of psychological and physical symptoms in a randomized control trial (RCT)

Abstract

To investigate the mechanism(s) of action of mindfulness based stress reduction (MBSR(BC)) including reductions in fear of recurrence and other potential mediators. Eighty-two post-treatment breast cancer survivors (stages 0-III) were randomly assigned to a 6-week MBSR(BC) program (n = 40) or to usual care group (UC) (n = 42). Psychological and physical variables were assessed as potential mediators at baseline and at 6 weeks. MBSR(BC) compared to UC experienced favorable changes for five potential mediators: (1) change in fear of recurrence problems mediated the effect of MBSR(BC) on 6-week change in perceived stress (z = 2.12, p = 0.03) and state anxiety (z = 2.03, p = 0.04); and (2) change in physical functioning mediated the effect of MBSR(BC) on 6-week change in perceived stress (z = 2.27, p = 0.02) and trait anxiety (z = 1.98, p = 0.05). MBSR(BC) reduces fear of recurrence and improves physical functioning which reduces perceived stress and anxiety. Findings support the beneficial effects of MBSR(BC) and provide insight into the possible cognitive mechanism of action.

Figures

Figure 1

Hypothesized Biobehavioral Logic Model postulates how change in fear of recurrence as a result of participation in the MBSR program may mediate a range of positive changes in psychological and physical symptoms and quality of life.

Figure 2

Three-variable framework used to assess mediation effects. In this model, MBSR (X1) is assumed to have both a direct and indirect path to the outcome perceived stress (Y). “c” is the direct path, and “a → b” is the indirect path passing through the mediating variable fear of recurrence (X2).

Figure 3

Baseline to 6-week changes in perceived stress by random assignment (MBSR (M) versus Usual Care (C)). The data are further stratified by baseline to 6-week change in fear of recurrence (potential mediator) using the median split of th and 95th percentiles, respectively.

Figure 4

Baseline to 6-week changes in state anxiety (left side) and trait anxiety (right side) by random assignment (MBSR (M) versus Usual Care (C)). The data are further stratified by baseline to 6-week change in fear of recurrence (potential mediator) using the median split of th and 95th percentiles, respectively.