Background: Grandparents play a crucial role in providing their families with love, support, and wisdom, often also supporting them in practical and financial ways. The psychosocial effects experienced by grandparents when a grandchild is diagnosed with an illness can be significant, including increased stress, anxiety, grief, and disruptions in their own lives. Yet, the experience of grandparents is often overlooked in the literature.

Methods/design: The GROKids Project aims to investigate how grandparents are affected by a grandchild's cancer diagnosis. It employs a mixed-methods approach and consists of three studies: a longitudinal cohort study (Study 1) and a qualitative study (Study 2) involving grandparents of children with a recent cancer diagnosis, and a cross-sectional study (Study 3) of grandparents of childhood cancer survivors. Study 1 covers four time points over two years after the cancer diagnosis, while Study 2 explores the lived experiences of a subsample of these grandparents. Study 3 collects data from grandparents of childhood cancer survivors diagnosed 3 to 10 years ago. Participants are recruited across eight pediatric oncology centers in Switzerland, and through patient advocacy and support groups. Eligibility criteria include having a grandchild diagnosed with cancer and being fluent in German, French, or Italian. Study procedures involve requesting grandparents' contacts from eligible families, and later contacting grandparents, providing study information, obtaining informed consent, and sending out questionnaires by post or online. Reminder calls and mails are used to improve response rates. Data analysis includes multilevel regression (Study 1), thematic analysis (Study 2), and regression analyses (Study 3). Various validated questionnaires are used to assess physical health and overall well-being, psychological health, internal, and external factors.

Discussion: This project addresses the gaps in understanding the psychosocial effects on grandparents having a grandchild diagnosed with cancer. It utilizes a comprehensive approach, including multiple methodologies and considering the broader family context. The project's strengths lie in its mixed-methods design, longitudinal approach, and inclusion of the perspectives of the sick children, siblings, and parents, besides grandparents. By gaining a more profound understanding of grandparents' experiences, researchers and healthcare professionals can develop targeted interventions and support services to address grandparents' unique needs.