Diagnostic Intervals in Children, Adolescents and Young Adults with Primary Bone Sarcoma: A Systematic Review

Background/Objectives: Survival in children, adolescents and young adults (CAYA) with bone sarcoma remains inferior to that of many other early-life cancers. Early recognition and treatment initiation may reduce the risk of presenting with advanced disease. We aimed to synthesize evidence on five predefined diagnostic intervals, separately synthesize pathway-specific intervals, and identify factors associated with diagnostic interval duration. Methods: A systematic review was conducted according to PRISMA guidelines. We included studies reporting the duration of a diagnostic interval in at least five patients aged 0-39 years with primary bone sarcomas, including osteosarcoma, Ewing sarcoma, and less common histological subtypes. MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and Scopus were searched for studies published between 2000 and 2025. Risk of bias was assessed using a custom domain-based tool. Results: Twenty-nine studies including 9271 patients from high-income countries met the inclusion criteria. Substantial heterogeneity in study design, populations, and interval reporting precluded meta-analysis. Reported median intervals were patient intervals of 13-84 days, diagnostic intervals of 15-123 days, total diagnostic intervals of 28-150 days, treatment intervals of 7-24 days, and total intervals of 66-88 days. Older age within the CAYA population and axial tumor location were the factors most consistently associated with longer diagnostic intervals. No consistent association between diagnostic interval duration and survival was identified. Pathway-specific intervals provided additional insight into different components of the diagnostic pathway, particularly after initial healthcare contact, although evidence remained limited. Conclusions: Diagnostic interval durations varied substantially across studies, reflecting methodological heterogeneity and differences in diagnostic pathways. Standardized prospective studies are needed to strengthen the evidence base.