MINDSET was the first of a number of comparative effectiveness clinical trials undertaken by our group, with the intention to compare MBCR to an already established and efficacious psychosocial intervention for cancer survivors. We felt it was past time to move beyond simple waitlist or usual care controlled trials for a tougher test of effectiveness. We chose Supportive Expressive Group Therapy as the comparator because it had a strong track record of efficacy for breast cancer survivors, had a similar format and contact hours to MBCR, yet targeted different mechanisms, focusing on emotional expression and group support. In this multi-site trial conducted in Calgary and Vancouver, we focused on both psychosocial and biological outcomes, had a large sample size to allow exploration of treatment moderators, screened to only include women with significant baseline distress, and followed women for a full year post-intervention.

Primary Outcomes & Telomeres

The primary outcome paper was published in JCO, and showed that while both MBCR and SEGT had benefits over time compared to a minimal intervention control, MBCR had stronger effects on stress, mood and quality of life, as well as improved cortisol slopes

Carlson, L.E. , Doll, R., Stephen, J., Faris, P., Tamagawa, R., Drysdale, R., and Speca, M., (2013) . Randomized Controlled Trial of Mindfulness-Based Cancer Recovery Versus Supportive Expressive Group Therapy for Distressed Survivors of Breast Cancer (MINDSET). JCO,2013 Sep 1;31(25):3119-26, 2013

The results of a novel analysis of telomere length in a subsample of the MINDSET women from Calgary showed, for the first time, an effect of both psychosocial interventions on telomere length. While women in the control condition without any intervention showed shortening of TL over the course of four months, women in both MBCR and SEGT maintained the original length of their telomeres:

Carlson, L.E., Beattie, T.L. Giese-Davis, J., Faris, P., Tamagawa, R., Fick, L.J., Degelman, E.S. & Speca, M. (2014). Mindfulness-based cancer recovery and supportive-expressive therapy maintain telomere length relative to controls in distressed breast cancer survivors. Cancer, 2015Feb1: 121(3): 476-484. DOI: 10.1002/cncr.29063

Baseline Factors, Follow-Up, & Mediators

We also explored whether a host of baseline factors such as personality, emotional suppression, repression or levels of distress predicted differential outcome across the two groups, but the only factor that seemed important in predicting better outcomes was whether women got the group they preferred

Carlson, L. E., R. Tamagawa, J. Stephen, R. Doll, P. Faris, D. Dirkse, and M. Speca. (2014). Tailoring Mind-Body Therapies to Individual Needs: Patients' Program Preference and Psychological Traits as Moderators of the Effects of Mindfulness-Based Cancer Recovery and Supportive-Expressive Therapy in Distressed Breast Cancer Survivors. J Natl Cancer Inst Monogr (2014)2014 (50): 308-314. doi:10.1093/jncimonographs/lgu034

Finally, the 6 and 12 month follow-up data showed that while women in both active interventions improved pre- to post-intervention, women in MBCR improved more than those in SEGT, and all women stayed at about the level of distress they were at post-intervention over the duration of the year of follow-up:

Carlson, L.E., Tamagawa, R., Stephen, J., Drysdale, E., Zhong, L., Speca, M. (2016). Randomized-controlled trial of mindfulness-based cancer recovery versus supportive expressive group therapy among distressed breast cancer survivors(MINDSET): long-term follow-up results. Psycho-Oncology (2016), DOI: 10.1002/pon.4150

We did further work on the MINDSET study data, trying to determine mediators of change across the two interventions, targeting the two central posited mediators for MBCR and SEGT (mindfulness and social support, respectively). Here we found to our surprise that only improvements in social support mediated changes in the MBCR group:

Schellekens, M.P.J., Tamagawa, R., Labelle, L.E., Speca, M., Stephen, J.,  Drysdale, E.,  Sample, S., Pickering, B.,  Dirkse, D.,  Savage, L.L., Carlson, L.E., (2016). Mindfulness-Based Cancer Recovery (MBCR) versus Supportive Expressive Group Therapy (SET) for distressed breast cancer survivors: evaluating mindfulness and social support as mediators. J Behav Med DOI 10.1007/s10865-016-9799-6. Published online October 8, 2016