Peer support interventions of adolescent and young adult childhood cancer survivors: A mixed methods systematic review

Abstract

Purpose: Peer support has emerged as a developmentally appropriate approach to address the psychosocial and behavioral needs of adolescent and young adult childhood cancer survivors (AYA CCS). Current evidence on peer support for AYA CCS remains fragmented, with qualitative and quantitative findings rarely combined to explain how and why these interventions exert their effects. This mixed-methods systematic review aimed to investigate the effectiveness, mechanisms, and contextual influences of peer support interventions for AYA CCS. Methods: Searches across eight databases identified quantitative, qualitative, and mixed-methods studies involving peer support interventions for AYA CCS aged 15-39 years. Quantitative outcomes were integrated with qualitative findings using a convergent segregated approach. Results: Twenty-six studies were included. Quantitative evidence indicated improvements in emotional wellbeing, social support, coping, self-efficacy, and selected health behaviors; however, the findings for quality of life and identity-related outcomes were heterogeneous. Qualitative synthesis identified core relational mechanisms such as belonging, normalization, emotional safety, reciprocity, shared meaning-making, and identity reconstruction, explaining the observed quantitative benefits and contextualized key divergences (such as a response shift phenomenon and high clinical demand despite null efficacy). One-on-one and structured peer mentoring programs had stronger and more consistent effects than asynchronous or app-based interventions. Conclusion: Peer support is a multifaceted and impactful strategy that supports psychosocial adaptation and health-related behaviors among AYA CCS. Programs fostering meaningful peer relationships and relational depth appear most effective. Future research should clarify the mechanisms of change and optimize hybrid or digitally supported models to enhance accessibility while preserving relational quality.