Background: Effective communication in support of clinical decision-making is central to the pediatric cancer care experience for families. A new laboratory derived pharmacogenetic test (LDT) that can diagnose difficult-to-treat brain cancers has been developed to stratify children based on their ability to respond to available treatment; however, the potential implementation of the LDT may make effective communication challenging since it can potentially remove the option for curative treatment in those children identified as non-responders, i.e. those with a catastrophic diagnosis. Objective: We solicited the perspectives of parents of children with difficult-to-treat brain cancer on communication preferences surrounding the potential implementation of the LDT in standard care using deliberative stakeholder consultations. Methods: Eight bereaved parents of children who succumbed to difficult-to-treat brain cancer, and four parents of children currently undergoing treatment for similar cancers attended separate small-group deliberative consultations – a stakeholder engagement method that enables the co-creation of recommendations following the consideration of competing arguments and diverse opinions of parents with different experiences. In the small-group consultations (Phase I), parents discussed four questions about potential communication issues that may arise with the LDT in practice. In Phase II, a total of five parents from both stakeholder groups (4 bereaved and 1 in current treatment) attended a consultation, known as the 'mixed' consultation, with the purpose of co-developing concrete recommendations for implementation of the LDT. Results: Explaining the risks, benefits, and accuracy of the LDT were considered essential to parents. Once an LDT-based diagnosis/prognosis can be made, parents valued honesty, empathy, and clarity in communication. Parents also requested that all results and treatment options be presented to them in measured doses, and in an unbiased manner over the course of several meetings. This communication strategy allowed sufficient time to understand and accept the diagnosis/prognosis, particularly if it was catastrophic. Continuous access to the appropriate psychological and social support or counselling at and post-diagnosis was also strongly recommended. Conclusions: Deliberants co-created family-centered recommendations surrounding communication issues of the LDT, providing guidance to pediatric oncologists that could implement the test in practice.