Prognostic Modeling for Bone Sarcomas based on a Large Prospective Cohort from a Tertiary Care Cancer Centre in India

Background: Outcomes of adolescents and young adults (AYA) with bone sarcomas inclusive of osteosarcoma (OGS) and Ewing’s sarcoma (ES) are impacted by various factors including inadvertent prior treatment and poor compliance. We aimed to identify prognostic factors and derive prognostic models for these patients. Methods: All AYA OGS and ES cases treated at our institute with the “OGS-12” and Ewing’s family of tumors-2001 (“EFT-2001”) protocols from 2011 to 2021, and 2013 to 2018 respectively, were prospectively analyzed. Results:. Among 606/748 (81.0%) AYA with non-metastatic osteosarcoma, significant factors included in the prognostic model were failure to complete protocol (hazard ratio (HR) 2.65, 95% confidence interval (CI) 1.65-4.26), prior treatment (HR 2.93, CI 1.4-6.1), necrosis <90% (HR 1.63, CI 1.24-2.1), joint involvement (HR 2.0, CI 1.49-2.69) and SAP> median (204 U/l) (HR 1.63, CI 1.24-2.14). Of 104/263 (39.5%) AYA ES, significant factors were failure to complete protocol (HR 2.84, CI 1.03-7.8), prior treatment (HR 6.37, CI 1.8-22.0), necrosis <100% (HR 8.73, CI 2.16-35.3), and tumor size >8cm (HR 2.64, CI 1.04-6.7). For 142/366 (38.8%) AYA with metastatic OGS, significant factors were failure to complete protocol (HR 5.29), metastases not amenable to local treatment (HR 1.96), necrosis <90% (HR 1.96), and >10 metastases (HR 2.44). For 38/82 (43.6%) AYA with metastatic extremity ES, significant factors were failure to complete protocol (HR 3.88) and metastases not amenable to local treatment (HR 10.6). Conclusion: We developed simple, effective prognostic models for AYA with bone sarcomas with wide applicability in LMIC.