Abstract
Cancer during adolescence and young adulthood (AYA; 18-39 years) can disrupt age-related milestones and impair social functioning. Many AYA patients report unmet social support needs and relationship changes, leading to isolation. This mixed-methods study explores social challenges among AYA patients actively seeking support through a communication tool, the 'AYA Match app', supporting communication with loved ones. Upon downloading the app, participants completed questionnaires on social support (MOS-SSS) and social functioning (EORTC CAT) and open-ended questions about social challenges. Eligibility included a first cancer diagnosis at AYA age and fluency in Dutch. The findings show that cancer negatively affected AYA patients' social functioning. Physical limitations and difficulty relating to peers caused isolation and feelings of loneliness. Some preferred solitude or withheld emotions to protect loved ones. Challenges included forming new relationships, feeling left behind as peers reach milestones, and struggling with a changed life perspective. Participants with children reported less social support. This study highlights the complex social challenges AYA cancer patients face. While support from loved ones is crucial, it may not always be effective. Personalized interventions like peer support, improved family communication, and tailored digital tools are needed to improve social well-being and quality of life in AYAs with cancer.