Acceptance and commitment therapy reduces psychological distress in patients with cancer: a systematic review and meta-analysis of randomized controlled trials

This study aimed to systematically review and meta-analyze the clinical efficacy of acceptance and commitment therapy (ACT) in patients with cancer and psychological distress. Randomized controlled trials (RCTs) from seven English electronic databases were systematically investigated from inception to 3 October 2023. A total of 16 RCTs from 6 countries with 711 participants were included in this study. Estimated pooled effect sizes (ESs) were calculated via inverse-variance random-effects or fixed-effects (I ≤ 50%) model and presented by standardized mean difference (SMD). Subgroup analyses were performed to reduce confounding factors and heterogeneity, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to evaluate the quality of the pooled ESs. The pooled ESs revealed that statistically significant improvements in anxiety [postintervention SMD = -0.41 (95% confidence interval (CI), -0.71, -0.11); = 0.008; I = 65%; follow-up SMD = -0.37 (95% CI, -0.66, -0.08); = 0.01; I = 29%], depression [postintervention SMD = -0.45 (95% CI, -0.63, -0.27);