Assessment of extent of surgical resection of primary high-grade osteosarcoma by treating institutions: A report from the Children's Oncology Group

Background Complete surgical resection of primary tumors is critical for long-term control of high-grade osteosarcoma. Uniform assessment of the extent of surgical resection is important in clinical trials, though the accuracy of this reporting has been poorly studied. Methods We conducted a retrospective cohort study of patients 5-40 years of age with newly diagnosed high-grade resectable osteosarcoma treated as part of the AOST0331 clinical trial at Children's Oncology Group institutions. The extent of surgical resection of the primary tumor was graded as wide or radical by the treating institution. Central assessment of the extent of resection by two orthopedic oncologists was compared with institutional assessment by reviewing pathology and operative reports. Results We included 956 patients who had data available for central review. The extent of resection reported by treating institutions was 536/956 (56%) radical and 420/956 (44%) wide. The extent of resection assessed by central review was 162/956 (17%) radical and 794/956 (83%) wide. The overall discordance rate for the cohort was 43%. Conclusions Institutional reports of radical resection in high-grade osteosarcoma significantly over-estimate the proportion of patients undergoing radical resection. This highlights the need for centralized review and improved accuracy of reporting of the extent of resection.