Mindfulness-Based Interventions for Depression, Anxiety, and Stress in Adults With Cancer: A Stratified Subgroup Meta-Analysis.

[BACKGROUND] Psychological distress, including depression, anxiety, and stress, is highly prevalent among adults with cancer. Mindfulness-based interventions (MBIs), such as Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Cognitive Therapy (MBCT), are increasingly used to address these symptoms. However, no prior review has comprehensively stratified MBI effects across intervention types, symptom domains, cancer populations, and geographic regions.

[AIMS] To evaluate the effectiveness of MBIs, including standard and adapted formats, on depression, anxiety, and stress in adults with cancer.

[METHODS] A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted in accordance with PRISMA guidelines. Six databases were searched from January 2010 to July 2025. Eligible studies included RCTs comparing MBIs to control conditions in adults with cancer, reporting validated outcomes for depression, anxiety, or stress. Random-effects meta-analyses were performed using Hedges' g, with subgroup analyses by intervention type, duration, geographic region, and cancer type.

[RESULTS] Across 84 effect sizes from 45 RCTs (N = 7395), mindfulness-based interventions were evaluated. MBIs significantly reduced depression (g = -0.92), anxiety (g = -1.06), and stress (g = -1.50). Modified MBIs MBIs demonstrated the largest effects (g = -1.57), followed by MBSR (g = -0.72) and MBCT (g = -0.68). The strongest effects were observed in breast cancer populations (g = -1.48) and in studies conducted in North America (g = -1.21) and Asia (g = -1.07).

[CONCLUSIONS] Mindfulness-based interventions (MBIs) were associated with reduced depression, anxiety, and stress in adults with cancer, though heterogeneity was high and evidence was largely from breast cancer trials. MBIs appear scalable, particularly for women with breast cancer, but broader conclusions remain limited. Findings support their inclusion in tailored psychosocial care, with a need for more diverse and rigorously controlled research.