Abstract
OBJECTIVES: This systematic review aimed to evaluate the effectiveness of positive psychology interventions (PPIs) that are theoretically grounded and tailored to individuals across various stages and types of cancer. METHODS: Adhering to PRISMA guidelines, a comprehensive search of peer-reviewed and gray literature was conducted across seven databases and supplementary sources, including Google and Google Scholar. Meta-analyses were performed using standardized mean differences (Hedges' g) to assess the impact of PPIs on various psychological, physiological, and quality of life (QOL) outcomes. The methodological quality of included studies was appraised using the McMaster Critical Appraisal Tool, and the overall body of evidence was graded using the NHMRC FORM framework. RESULTS: Eighteen studies involving 1382 participants were included. PPIs significantly improved psychological wellbeing domains such as post-traumatic growth, positive emotions, engagement, meaning, and positive relationships, with effect sizes ranging from moderate to large (p < 0.05). Improvements were also observed in QOL and sexual functioning, though these outcomes were assessed in fewer studies. In contrast, limited or inconsistent effects were noted for accomplishment, psychological distress, physical functioning, and pain. High heterogeneity across studies highlighted variability in intervention designs and participant populations. CONCLUSIONS: PPIs hold promise as an integrative approach to psycho-oncology care in enhancing psychological wellbeing among cancer survivors. While their effects on psychological distress and specific concerns like sexual dysfunction warrant further research, PPIs represent a valuable framework for supporting the multifaceted needs of cancer survivors. Standardization of interventions and integration into multidisciplinary care models are recommended to maximize their clinical utility.