Extended data_Evidence Distribution Across Osteosarcoma Tumour Types: An Evidence Gap Map to inform the WHO Classification of Tumours

This study aims to examine the distribution and strength of scientific evidence across osteosarcoma types as defined in the WHO Classification of Tumours. Using an evidence gap map approach, studies published between 2018 and 2024 were systematically reviewed, focusing on key tumour characteristics such as pathogenesis, histopathology, diagnostic molecular pathology, prognosis, and prediction. The findings reveal a clear imbalance in both the quantity and quality of available evidence, with most research concentrated on osteosarcoma, while rarer types remain understudied. This work highlights critical gaps in the literature and identifies priority areas for future research to support improved tumour classification and clinical decision-making.