Perceived stress moderates the effects of a randomized trial of dance movement therapy on diurnal cortisol slopes in breast cancer patients

Women with breast cancer are at risk of psychosocial distress and may suffer from aberrant diurnal cortisol rhythms. Dance movement therapy (DMT), a movement-based psychotherapy that incorporates exercise and artistic components, has demonstrated stress reduction effects. This study examined the effects of DMT on the diurnal cortisol rhythms of breast cancer patients undergoing radiotherapy treatment and the role of perceived stress in producing such effects. The study sample comprised 121 Chinese breast cancer patients randomized to the DMT (n = 63) and control (n = 58) groups. The intervention consisted of six 1.5-h group sessions held twice weekly over the course of radiotherapy. Participants completed validated self-report measures of perceived stress, fatigue, pain, and sleep disturbance and provided five salivary cortisol samples at baseline (Time 1) and post-intervention (Time 2). Moderated mediation analysis was used to evaluate the intervention effect on Time 2 diurnal cortisol slopes. Despite the absence of a significant DMT effect on diurnal cortisol slopes (B = −0.55, 95% CI = −1.20 to 0.08, β = −0.14), baseline perceived stress significantly moderated the intervention effect (B = −0.18, 95% CI = −0.32 to −0.05, β = −0.30). At high levels of baseline perceived stress (1 SD above the mean), the DMT group showed a steeper cortisol slope (M = -7.14) than the control group (M = −5.80) at Time 2. The present findings suggest that DMT might have a beneficial effect on diurnal cortisol slopes in breast cancer patients with high levels of distress.