This manuscript examines how AYAs with advanced cancer experience undergoing complete genomic analysis within standard oncology care. While this approach may refine diagnoses or point to personalised treatment options beyond routine pathways, its immediate clinical impact is often limited. Even so, AYAs value having the opportunity, as it reassures them that all possibilities have been explored. Yet misunderstandings about the purpose of testing, challenges in interpreting results, and limited awareness of potential hereditary findings can hinder its use. To support AYAs effectively, healthcare professionals should provide clear, comprehensive and age appropriate information about both the benefits and the limitations of this analysis. (https://jmg.bmj.com/content/early/2026/03/27/jmg-2025-111368)