Actionable diagnostic delay in primary malignant bone tumors: a trigger-to-action framework for first-contact...

Primary malignant bone tumors may initially resemble common musculoskeletal conditions, creating uncertainty about when first-contact clinicians should escalate care. This narrative review integrates selected guidelines, diagnostic-pathway studies, and imaging and biopsy literature to translate established principles into practical decisions before specialist referral. We propose actionable diagnostic delay as a descriptive, unvalidated framework: the potentially avoidable interval between a documented clinical trigger for escalation and initiation of the corresponding action. It complements, rather than replaces, established patient, diagnostic, referral, and treatment intervals. Concerning symptom trajectories, examination findings, aggressive or indeterminate imaging, and clinical-imaging-pathology discordance guide reassessment, imaging, referral, or coordinated biopsy. Plain radiographs are the first imaging step; persistent clinical suspicion despite normal radiographs warrants MRI or specialist referral. Referral should not await MRI when access is limited. A 2-4-week reassessment window is proposed only for mild, stable, low-suspicion presentations with adequate radiographs showing no suspicious or indeterminate lesion and is not an evidence-validated waiting period. Suspected fracture or acute neurological compromise requires emergency assessment. Metastatic carcinoma and myeloma are considered in parallel in the appropriate clinical context, while solitary or atypical aggressive lesions require a sarcoma-safe diagnostic pathway. Contemporary biopsy evidence supports specialist planning and radiology-pathology correlation, but diagnostic accuracy varies with case mix and sampling. Associations between diagnostic intervals and survival remain inconsistent and vulnerable to confounding by tumor biology. The framework therefore prioritizes diagnostic and procedural safety rather than a presumed survival benefit. Its performance, referral burden, and applicability across healthcare systems require prospective evaluation.