6748 Time to diagnosis of osteosarcoma: does diagnostic delay impact outcome and can we improve diagnosis?

Objectives Osteosarcoma is the most common primary bone malignancy.1 Due to its vague presenting features and rarity, osteosarcoma diagnosis is challenging. Evidence is mixed regarding whether time to diagnosis of osteosarcoma impacts patient outcome. The COVID-19 pandemic has been associated with paediatric malignancy diagnostic delay2 and prolonged diagnostic time has been associated with poor outcomes.3 The aims of this study were to identify: Does time to diagnosis impact patient outcome? Did the COVID-19 pandemic impact time to diagnosis? Are there any identifiable causes of delayed diagnosis? Can diagnosis be improved? Methods A retrospective study of paediatric patients (Results This cohort comprised 24 patients – 22 patients with primary tumours, 2 patients with secondary tumours. 21 patients had appendicular skeletal involvement, vs 3 patients with axial skeletal involvement. Average age at diagnosis was 11.3 years and average time to diagnosis was 72.4 days. Average time to diagnosis of patients in remission vs deceased patients did not significantly differ (77.4 days vs 65.9 days). Prolonged time to diagnosis was seen during and following the COVID-19 pandemic (109.6 days vs 52.9 days). Increased time to diagnosis was seen in tumours affecting the axial skeleton compared to the appendicular skeleton (133.7 days vs 59.0 days). Patients referred via 2-week wait had higher mortality rates compared to patients presenting via other pathways. 4/24 patients had x-rays completed early in their diagnostic journey, but osteosarcoma was not considered at this stage. Conclusion Prolonged time to diagnosis did not appear to influence mortality in this patient cohort. However, diagnostic delay is undoubtedly a major cause of emotional turmoil to the patient and their families. The COVID-19 pandemic appears to have negatively impacted osteosarcoma diagnostic pathways. Due to small sample size, results should be interpreted with caution. Review of current 2-week wait criteria, with more emphasis on atypical presentations, should occur. A normal x-ray does not exclude pathology. MRI should be considered in patients with persistent bony pain or swelling. Future work should investigate mortality rates before and after the COVID-19 pandemic, to determine if disruptions to diagnosis impacted mortality. References Beird, et al. Nature Reviews Disease Primers, 2022. Quarello, et al. Journal of Adolescent and Young Adult Oncology, 2022. Yoshida, et al. Journal of Bone Oncology, 2021.