Intervention studies on shared decision-making with adult patients for treatment among cancer: A systematic review and meta-analysis

Patients have the right to participate in the decision-making on their treatments. A shared decision-making (SDM) approach has been extensively studied and applied across a wide range of medical conditions beyond cancer, demonstrating various benefits. There is increasing support for involving cancer patients with SDM for complex treatments, but most previous studies on SDM in cancer patients were focused on children or the elderly. The purpose of this study was to synthesize findings from intervention studies on SDM regarding knowledge, decision satisfaction, decision conflict, and decision regret. Three electronic databases (PubMed, CINHAL, and Web of Science) were searched from their inception to June 2023. We included controlled trials on SDM in cancer patients over 18 years of age. Potential target studies were identified using a set of keywords with the aim of including all kinds of SDM interventions. Data were extracted using a standardized form. Quality appraisal was based on the Cochrane Risk of Bias Tool. Of the 2759 citations retrieved, 8 studies with a total of 1505 participants met the inclusion criteria. The frequency of interventions ranged from 1 to 3 times per week. SDM methods included weekly assignments, live action videos, and brochures. Treatment preference congruence was higher for intervention groups. Synthesized outcome measurements that reached statistical significance included satisfaction (mean difference in satisfaction questionnaire = 0.18; 95% confidence interval CI: 0.07-0.29), decision regret (mean difference in decision regret scale = -0.27; 95% CI: -0.04 to -0.10), decision conflict (mean difference in decision regret scale = -0.49; 95% CI: -0.96 to -0.02), and knowledge (mean difference in knowledge score = 0.39; 95% CI: 0.01-0.76) after SDM interventions for adult cancer patients. Although SDM has been delivered to adult cancer patients in various forms, overall it promoted satisfaction and knowledge of the patients while reducing their decision regret and decision conflict. Still, the development of standard assessment tools for the outcomes of SDM interventions is needed to identify more effective formats.