The mirrored burden and accountable handovers in cancer survivorship: co‑designing a post‑treatment transition standard.

Post-treatment transitions after active cancer care often lack clear ownership, timelines and closure rules, shifting coordination work onto survivors and staff. We aimed to identify how these failures arise and to co-design a handover standard for post-treatment survivorship care. In a two-stage qualitative study, Stage A involved semi-structured interviews with survivors and professionals (n = 65) across head and neck, colorectal and gastrointestinal stromal tumour pathways; Stage B comprised four co-design workshops (n = 21). We identified a mechanism we term mirrored burden, in which routine letters and electronic records fail to make responsibility explicit and both survivors and staff end up chasing care. Co-design produced a four-component handover standard centred on accountable correspondence, a clinically senior survivorship lead practitioner with delegated authority, clinic-based resolution capacity, and equity safeguards for non-digital access and communication needs, plus four equity-stratified audit-ready feasibility indicators for service-level evaluation.