In the literature, the experience of siblings of children and adolescents with cancer has been extensively explored, mainly along two lines of research: the psychological impact of the illness on the typically developing siblings, and the support interventions designed for them. Instead, the effect of cancer on the sibling relationship itself has received comparatively little attention. This systematic integrative review aims to identify studies specifically focused on sibling relationships, to understand whether and how these relationships change during the illness, and what impact these changes may have on broader family dynamics. The review follows the PRISMA guidelines and includes seven studies identified through a comprehensive literature search. The findings were analyzed according to the research methods used and the themes investigated. Most studies employed quantitative methods, such as questionnaires, while only two used qualitative approaches, including interviews and focus groups, primarily with typically developing siblings. The studies reveal that siblings perceive changes in their relationship in ambivalent ways reporting both a general deterioration and an increased sense of closeness. These changes are also linked to their perceptions of the parental relationship. The results highlight a clear need for further research into the specific effects of cancer on sibling relationships and suggest indications for the psychological support to the whole family. More qualitative studies are recommended to explore the nuanced nature of these changes, with attention to the perspectives of both typically developing and siblings with cancer.
