Barriers to Diagnostic and Treatment Delay in Oral Cancer Across Income Settings: Systematic Review.

OBJECTIVE: To synthesize barriers associated with delays in the diagnosis and initiation of treatment of oral cancer across high-income countries (HICs) and low- and middle-income countries (LMICs) contexts, aligned with the Aarhus diagnostic-therapeutic intervals. METHODS: A systematic literature search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Embase, and ProQuest. Observational, qualitative, and mixed-methods studies reporting patient-reported perceptions or system-level barriers affecting the diagnostic-therapeutic pathway and associated with diagnostic or treatment delays in adult oral cancer were included. Data were narratively synthesized, and identified barriers were semantically standardized and mapped to the Aarhus intervals. RESULTS: Sixteen studies were included. Barriers were categorized into psychosocial, symptom appraisal, health literacy, structural, professional-related, and organizational domains. Studies focusing on the patient interval most frequently reported psychosocial and appraisal-related barriers. Studies examining diagnostic, composite, or total intervals more commonly identified professional-related and organizational barriers. Studies from LMICs more frequently addressed extended segments of the care pathway and reported nonbiomedical management strategies, health literacy-related barriers, and professional or structural barriers beyond the patient interval. CONCLUSION: Delays in oral cancer care reflect an interconnected, trajectory-based process shaped by interacting individual, professional, and system-level factors, supporting the need for integrated interventions across the care continuum.