Undifferentiated pleomorphic sarcoma of bone (UPSB) treated in the German-speaking countries. A report of 132 unselected patients from the Cooperative Osteosarcoma Study Group (COSS)
Year: 2026
Type: article
Study design: Observational Study
Abstract: PURPOSE: To describe Undifferentiated Pleomorphic Sarcoma of Bone (UPSB) treated in Germany, Austria, or Switzerland and using the same treatment-approach as for osteosarcoma. PATIENTS AND METHODS: The database of the Cooperative Osteosarcoma Study Group (COSS) was screened for UPSB. Eligible patients were evaluated for patient, tumor, and treatment related variables, and outcomes. RESULTS: One-hundred thirty-two eligible patients were identified (median age 41.7 (range: 10.3-74.6) years; males 58%; preceding malignancies 11%; tumor-sites extremities 86%, trunk 12%, head & neck 2%). Relative tumor size was < 1/3 of the involved bone in 83% of evaluable cases, pathologic fractures were present in 14% (limb-primaries only), and primary distant metastases in 6%. All patients received chemotherapy and 96% surgery for their primary (81% limb-salvage for extremity lesions). The response rate to preoperative chemotherapy was 38%. After a median follow-up of 3.9 (1 day-34.1) years for event-free and 5.2 (0.2-34.1) years for overall survival, the 5 year event-free and overall survival probabilities were 63% (standard error: 5%) and 70% (4%), respectively. Younger patient age, an extremity tumor, and localized disease predicted superior outcomes, pathologic fractures and limb-salvage surgery worse. The extent of tumor response to pre-operative chemotherapy seemed to have no impact on prognosis. DISCUSSION: UPSB generally affects considerably older persons than does the more frequent osteosarcoma. Despite a lower response rate to preoperative chemotherapy, its prognosis is at least comparable, if not better. Several prognostic factors impacting outcome could be defined. These results provide a benchmark for this rare disease.
Authors: Stefan S. Bielack, Dimosthenis Andreou, Daniel Baumhoer, Claudia Blattmann, Godehard Friedel, Birgit Fröhlich, Semi Ben Harrabi, Leo Kager, Thekla von Kalle, Torsten Kessler, Matthias Kevric, Antonia Knoll, Thomas Kühne, Peter Reichardt, Benjamin Sorg, Reinhard Windhager, Stefanie Hecker-Nolting
Institutions: University Hospital Münster, Olgahospital, Klinikum Stuttgart, Essen University Hospital, Stiftung Universitätsmedizin Essen, University of Basel, University Hospital of Basel, Universitätsklinikum Tübingen, University of Tübingen, Heidelberg University, University Hospital Heidelberg, University of Vienna, St Anna Children's Hospital, St. Anna Children's Cancer Research Institute, Medical University of Vienna, University of Münster, University Children’s Hospital Basel, Helios Hospital Berlin-Buch
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $4,390
OpenAlex ID: W7124864850