 This is an observational international multi-center study in which data on consecutive patients with UUT tumours are collected. Centers from every continent may apply for participation in this registry. Data will be collected from consecutive patients over a five year period. Patients data at baseline visit, at one year, three years and five years after inclusion in the registry will be recorded, as well as data on intra- and postoperative complications, recurrence and survival in the whole study period. Data from all participating centers will be collected through electronic case report forms eCRFs, with use of an online Data Management System DMS, which is located and maintained at the CROES Office. 