Randomized Controlled Trial of Group-Blended and Individual-Unguided Online Mindfulness-Based Cognitive Therapy to Reduce Psychological Distress in People With Cancer

Objective: Online mindfulness-based cognitive therapy (eMBCT) can reduce psychological distress in people with cancer, but adherence and scalability could be improved. Through co-creation, we developed two eMBCT formats: group-blended and individual-unguided. This trial compared the effects of the two eMBCT to care as usual (CAU) on psychological distress and other mental health outcomes in people with cancer. Methods: In this parallel, three-armed randomized controlled trial, people with cancer were randomly allocated to group-blended eMBCT, individual-unguided eMBCT, or CAU. Participants completed baseline, mid-treatment, post-treatment, and 3 months follow-up assessments. The primary outcome analyzed in the intention-to-treat (ITT) population was psychological distress (Hospital Anxiety and Depression Scale) at post-treatment. Results: In total, 186 participants were randomized to group-blended eMBCT (N = 57), individual-unguided eMBCT (N = 75), or CAU (N = 54). Most participants were female (81%) with breast cancer (49%), and treated with curative intent (76%). In ITT analyses, group-blended eMBCT participants reported significantly lower levels of psychological distress at post-treatment (Cohen's d = 0.38) and follow-up (Cohen's d = 0.64) than those receiving CAU, while individual-unguided eMBCT participants only had significantly less psychological distress at follow-up (Cohen's d = 0.48). Additionally, participants in group-blended eMBCT had less rumination and greater mindfulness, decentering, and self-compassion than those in CAU at follow-up. Participants in individual-unguided eMBCT had greater decentering than those in CAU at post-treatment and follow-up, and less rumination and greater mindfulness skills than CAU at follow-up. Conclusions: Compared to CAU, both eMBCT conditions were effective in reducing psychological distress and could be an accessible, and potentially low-cost intervention to reduce distress in people with cancer. Trial registration: Dutch Registry CCMO, NL73117.091.20; clinicaltrials.gov, NCT05336916.