ESTRO 2025 - Abstract Book

S1659

Clinical - Sarcoma & skin cancer & malignant melanoma

ESTRO 2025

180

Digital Poster Treatment strategies for soft-tissue sarcoma patients: a population-based analysis on German clinical cancer registry data Jörg Andreas Müller 1 , Karl Stefan Delank 2 , Anne von Rüsten 3 , Kevin Laudner 4 , Constanze Schneider 3 , Jessica Isabel Selig 5 , Ian Wittenberg 6 , Dirk Vordermark 1 , Daniel Medenwald 7,1 1 Department of Radiation Oncology, University Hospital Halle (Saale), Halle (Saale), Germany. 2 Department of Orthopedics, Trauma, and Reconstructive Surgery, University Hospital Halle (Saale), Halle (Saale), Germany. 3 Clinical Cancer Registry Brandenburg-Berlin, Clinical Cancer Registry Brandenburg-Berlin (Klinisch-epidemiologisches Krebsregister Brandenburg-Berlin gGmbH), Berlin, Germany. 4 Department of Health Sciences, University of Colorado Colorado Springs, Hybl Sports Medicine and Performance Center, Colorado Springs, CO, USA. 5 Cancer Registry of Saxony, Cancer Registry of Saxony (Krebsregister Sachsen gGmbH), Dresden, Germany. 6 Clinical Cancer Registry Saxony-Anhalt, Clinical Cancer Registry Saxony-Anhalt (Klinische Krebsregister Sachsen-Anhalt GmbH), Magdeburg, Germany. 7 University Clinic for Radiation Therapy, University Hospital Magdeburg A. ö. R, Magdeburg, Germany, Magdeburg, Germany Purpose/Objective: Sarcomas represent a heterogenous group of neoplasms, and there is a lack of data describing treatment patterns in Germany. This study evaluated treatment strategies and therapeutic outcomes based on German cancer registry data. Our findings were then compared to the German S3 and NCCN guideline recommendations. Material/Methods: From 2000 to 2023, we identified patients diagnosed with soft tissue sarcomas (STS) from the German clinical cancer registries of Brandenburg-Berlin, Saxony and Saxony-Anhalt. Sarcoma cases of all clinical or pathological T stages (T1-T4), all N-stages (N0-3) without distant metastasis corresponding to the Union for International Cancer Control stages I to III were considered. Using logistic regression and Cox-proportional hazard analysis, we determined predictors of overall survival (OS). Propensity-score matching (PSM) was used to balance covariates and to reduce potential bias. We included sex, age at diagnosis, tumor localization, histological grade, Eastern Cooperative Oncology Group (ECOG) performance status, T- and N-status and treatment as parameters in our regression models. Results: Surgery without RT (hazard ratios (HR) 0.96, 95% confidence interval (CI) 0.77-1.21) was not adverse compared to postoperative radiotherapy (RT). Patients treated with preoperative RT or RT alone had worse survival probabilities compared to patients treated with postoperative RT (preoperative RT vs. postoperative RT HR: 1.39, 95% CI 0.99 1.94; RT alone vs. postoperative RT HR: 2.20, 95% CI 1.83-2.65). Patients treated with postoperative RT had the best median survival rate (30 months, 95% CI: 26-35 months). Primary resected patients had a median survival of 23 months (95% CI: 11-37 months). In a subgroup analysis regarding histological grading, high-grade sarcoma patients treated with surgery alone had a higher mortality risk compared to patients treated with postoperative RT (postoperative RT vs. surgery alone, HR: 1.53, 95% CI 1.01-2.29). This effect could not be found for low-grade sarcoma patients (postoperative RT vs. surgery alone, HR: 0.94, 95% CI 0.63-1.38). Conclusion: Postoperative RT was beneficial for high-grad sarcoma patients in terms of OS compared to surgery without RT in our real-world data analysis. Age, histological grade, T-, and N-stage, treatment strategy and ECOG performance status were found to be prognostic factors in terms of survival.

Keywords: cancer registry, soft tissue sarcoma, treatment