1 Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Canada.
2 Child Health Evaluative Sciences, Hospital for Sick Children, Toronto, Canada.
3 Temerty Faculty of Medicine, University of Toronto, Toronto, Canada.
4 KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, Canada.
5 Institute of Health Policy Management and Evaluation, University of Toronto, Toronto, Canada.
6 Division of Hematology/Oncology, Hospital for Sick Children, Toronto, Canada.
7 Faculty of Health Sciences, University of Ottawa, Ottawa, Canada.
8 Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Canada.
9 Department of Psychology, Concordia University, Montreal, Canada.
10 Sue and Bill Gross School of Nursing, University of California Irvine, Irvine, California, United States of

Pain is one of the most prevalent and burdensome pediatric cancer symptoms for young children and their families. A significant proportion of pain episodes are experienced in environments where management options are limited, including at home. Digital innovations such as apps may have positive impacts on pain outcomes for young children in these environments. Our overall aim is to co-design such an app and the objective of this study was to explore the perceptions of children's parents about app utility, needed system features, and challenges. We recruited parents of young children with cancer and multidisciplinary pediatric oncology clinicians from two pediatric cancer care centers to participate in audio-recorded, semi-structured, co-design interviews. We conducted interviews structured around technology acceptance and family caregiving theories until data saturation was reached. Audio-recordings were then transcribed, coded, and analyzed using thematic analysis. Forty-two participants took part in the process. Participants endorsed the concept of an app as a useful, safe, and convenient way to engage caregivers in managing their young child's pain. Overall, the app was valued as a means to provide real-time, multimodal informational and procedural pain support to parents, while also reducing the emotional burden of pain care. Recommendations for intervention design included accessibility-focused features, comprehensive symptom tracking, and embedded scientific- and clinically-sound symptom assessments and management advice. Predicted challenges to app use included the workload burden it may place on parents and clinicians. The insights gathered will inform the design principles of our future childhood cancer pain digital research.