Supplementary Material for: Effect of Yoga on Psychological and Spiritual Outcomes in Cancer Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials with Meta-Regression

Introduction: Psycho-spiritual distress remains one of the most prevalent and pressing concerns throughout the cancer survivorship journey, impacting their existential integrity. Various yoga interventions have been examined for their potential to alleviate this distress, but their effects in cancer patients varied.

Methods: We searched seven databases (PubMed, Embase, Cochrane Central Register of Controlled Trials, PsycINFO, CINAHL, SportDiscus, and Web of Science) and two clinical trial registries from their inception to October 2024, without language restriction. The randomized control trials (RCTs) that compared the effects of yoga interventions with controls on psychological, spiritual, and emotional well-being among adults with cancer were included. The random effects pooled estimates (Hedges' g) and 95% confidence intervals (CIs) were calculated. Heterogeneity was assessed using I2. Moderators were identified through meta-regression.

Results: Fifty-five RCTs involving 3,608 participants (2,935 [81.3%] female; mean age range, 46-69 years) were included. Meta-analysis revealed that yoga interventions largely reduced anxiety (Hedges’ g, -0.82; 95% CI, -1.33 to -0.31; I2=88%), moderately-to-largely reduced depression (g, -0.62; 95% CI, -1.06 to -0.19; I2=85%), as well as mildly-to-moderately improved spiritual well-being (g, 0.31; 95% CI, 0.17 to 0.46; I2=0%) and emotional well-being (g, 0.23; 95% CI, 0.02 to 0.45; I2=47%).

Conclusion: Yoga effectively reduces anxiety and depression, and improves spiritual well-being and emotional well-being in cancer, underscoring their potential to improve the psychological and spiritual health of this population. More rigorously designed trials are needed to understand the optimal intervention parameters to maximize the effects of yoga on psychological outcomes.