BACKGROUND: Germline genomic sequencing (GS) is increasingly offered to children with cancer. To optimize integration into routine care, assessment of implementation barriers and a better understanding of healthcare professionals' perspectives and experiences are needed. METHODS: Healthcare professionals delivered trio germline GS to newly diagnosed pediatric and adolescent patients with cancer via the PREDICT completed questionnaires with qualitative and quantitative items. Each study site recorded reasons for eligible families' nonenrolment in PREDICT to identify barriers to recruitment. Quantitative data were analyzed via descriptive statistics, whereas qualitative data underwent inductive content analysis, with results integrated for interpretation. RESULTS: Thirty-three healthcare professionals participated, including 23 oncology professionals and 10 genetic professionals. Healthcare professionals perceived PREDICT as beneficial to participating and future families, and that perceptions of personal benefit and altruism were drivers of family uptake. Concerns included workforce capacity and potential family distress given the trio design and high-stress diagnosis setting. Barriers to recruitment related to clinical decision-making, family factors, and logistics. Although most rated their genetics/genomics knowledge as "good," regarding germline results, few were "very confident" interpreting (29%), explaining (32%), making treatment recommendations (9.7%), and providing psychosocial support to families (29%). They acknowledged a need for further training in these areas for trainees
yet, fewer were interested in training for themselves. CONCLUSION: Successful implementation of routine germline GS will require targeted strategies to address logistical issues and alleviate potential negative psychosocial impacts for families. Recognizing the escalating demand on genetics experts, upskilling of the current workforce and involvement of a broader spectrum of healthcare professionals are warranted.