Strengths and Limitations:
This is the largest, single-centre prospective analysis of prognostic factors for AYA with bone sarcomas globally, with the first prognostic model tailored for AYA with generalizable results for LMIC.
Limitations include the shorter follow-up and lower number of AYA with Ewing’s sarcoma, which is as expected for a rare cancer. Additionally, the prognostic scores for metastatic osteosarcoma, and for both non-metastatic and metastatic osteosarcoma could not be validated in a separation validation cohort due to lower sample sizes. Socioeconomic backgrounds of our patients were not assessed with objective scales such as the Kuppuswamy scale; however, surrogate parameters such as treatment duration as an indicator for compliance, prior inadvertent treatment and protocol completion were included in the analysis.