Effects of Mindfulness-Based Interventions on Patients with Anxiety in Cancer: A Systematic Review and Meta-Analysis

Objective: We synthesized the effects of mindfulness-based interventions (MBIs) on anxiety symptoms in adults with cancer. Method: We searched 11 electronic databases from inception to February 2024. We included studies comparing MBIs with usual care, waitlist controls, or no intervention for the improvement of patients with anxiety in cancer (CA). We only reviewed studies written in English. We used a random-effects model to compute the effect size. Funnel plot, Q statistics, and I² were used to test the heterogeneity across studies. We examined moderators to explore sources of heterogeneity. Results: Across 26 included studies, 1431 adults with cancer participated in MBIs; 1289 served as controls. Mean age ranged from 42.8 to 70.7 years. Most patients were females (56%), and patients with breast cancer and mixed cancer (55.53% and 26.20%, respectively). Overall, MBIs reduced anxiety in the experimental groups compared to control groups (Hedges' g = 0.977, 95% confidence interval = 0.61, 1.34, I² = 95%), but with substantial heterogeneity. In subgroup analysis, funding, setting, a priori power analysis, providing MBIs in adults with cancer and anxiety disorders, and measuring anxiety after postintervention were moderators affecting the pooled effect size. No other quality indicators moderated the effect sizes of MBIs on anxiety. Conclusion: MBIs appear efficacious in improving patients with CA, especially for those with mild-to-moderate anxiety symptoms. Clinicians and health providers might consider using MBIs as an alternative complementary treatment for improving or preventing anxiety disorders in adults living with cancer. With heterogeneity of studies, a large number of primary studies is needed to explore the source of heterogeneity.