Real‐World Achievement of Guideline‐Concordant Treatment and Survival in Osteosarcoma: A Nationwide Registry Study

Real-world achievement of guideline-concordant treatment in osteosarcoma remains unclear. This study aimed to determine stage-specific rates of guideline-concordant treatment, evaluate their association with survival outcomes, and identify factors associated with non-concordance. Patients with osteosarcoma between 2011 and 2020 were identified from the Japanese Bone and Soft Tissue Tumor Registry. Rates of guideline-concordant treatment and disease-specific survival (DSS) were investigated. Among 1149 patients, 969 (84%) received guideline-concordant treatment. Achievement rates were 85% for localized low-grade, 83% for localized high-grade, and 90% for metastatic osteosarcoma. In localized low-grade disease, guideline-concordant treatment was associated with superior 5-year DSS (97% vs. 68%, p = 0.007); trunk location was associated with non-concordance. In localized high-grade disease, guideline-concordant treatment was also associated with superior 5-year DSS (78% vs. 50%, p < 0.001); age > 40 years and trunk location were associated with non-concordance. The association between guideline-concordant treatment and superior DSS was observed in both patients ≤ 40 years (82% vs. 50%; p < 0.001) and > 40 years (61% vs. 50%; p = 0.030). However, in a sensitivity analysis restricted to localized high-grade extremity osteosarcoma, this association remained significant among patients aged ≤ 40 years. In metastatic disease, guideline-concordant treatment was associated with superior 2-year DSS (54% vs. 16%; p < 0.001). Overall, guideline-concordant treatment was associated with superior survival outcomes in osteosarcoma. Treatment feasibility appeared to substantially influence treatment achievement and survival, particularly among older patients. No significant geographic disparities in achievement rates were observed across Japan, indicating a high and uniform standard of care nationwide. Wide/radical surgical resection and perioperative chemotherapy remain crucial whenever clinically feasible.