Evaluating the Effect of Acceptance and Commitment Therapy on Post-traumatic Growth in Cancer Survivors: A Pilot Non-randomized Controlled Trial in a Greek Sample

At baseline, groups were comparable across demographic and clinical variables. Following the intervention, the IG showed significant increases in overall PTG and in the Personal Strength factor. Anxiety and cortisol levels significantly decreased in the IG compared with the CG, whereas reductions in depression and traumatic stress did not reach significance after adjusting for baseline scores. Conclusion: Findings suggest that a brief ACT-based intervention can meaningfully enhance key dimensions of PTG and reduce anxiety among cancer survivors. As a pilot non-randomised controlled study, effect sizes and feasibility outcomes support the development of larger, fully powered trials incorporating long-term follow-up and biological stress markers.