The aim of our research is to search for prognostic factors in patients with bone or soft tissue sarcomas: which characteristics predict a good survival rate (response to the established therapy)? Which characteristics predict the chance of local recurrence (e.g., giant cell tumor, atypical lipomatous tumor, malignant tumors)? Which characteristics predict the growth (rate) and potential degeneration of tumors with an intermediate character? etc. Imaging studies and real-life data from patients who were discussed, examined, and treated by the multidisciplinary tumor working group for bone and soft tissue tumors at UZ Gent (period 2000 – 2024) are supplemented, analyzed, and correlated with e.g. survival, local recurrences, growth rate, and metasatasis formation. For patients with available tissue and blood samples, a translational study will be conducted. Benchmarking is done with the Karolinska Institute based on multiple indicators.