Dropout Rate of Participants with Cancer in Randomized Clinical Trials That Use Virtual Reality to Manage Pain-A Systematic Review with Meta-Analysis and Meta-Regression.

: Virtual reality has emerged as a promising intervention for pain management in individuals with cancer. Although its clinical effects have been explored, little is known about participant adherence and dropout behavior. This systematic review and meta-analysis aimed to estimate the pooled dropout rate in randomized controlled trials using virtual reality to treat cancer pain; assess whether dropout differs between groups; and explore potential predictors of attrition. : We conducted a systematic search of PubMed, Web of Science, Scopus, and CINAHL up to April 2025. Eligible studies were randomized trials involving cancer patients or survivors that compared VR interventions for pain management with any non-VR control. Proportion meta-analyses and odds ratio meta-analyses were performed. Heterogeneity was assessed using the I statistic, and meta-regression was conducted to explore potential predictors of dropout. The JBI appraisal tool was used to assess the methodological quality and GRADE system to determine the certainty of evidence. : Six randomized controlled trials were included (n = 569). The pooled dropout rate was 16% (95% CI: 8.2-28.7%). Dropout was slightly lower in VR groups (12.7%) than in controls (21.4%), but the difference was not statistically significant (OR = 0.94; 95% CI: 0.51-1.72; I = 9%; GRADE: very low). No significant predictors of dropout were identified. : VR interventions appear to have acceptable retention rates in oncology settings. The pooled dropout estimate may serve as a reference for sample size calculations. Future trials should improve reporting practices and investigate how VR modality and patient characteristics influence adherence.