Timing and Outcomes of Adjuvant Radiotherapy for Soft Tissue Extremity Sarcomas

Abstract

This retrospective cohort study investigates the outcome of adjuvant radiotherapy in patients with soft-tissue extremity sarcomas, rare types of mesenchymal tumours that comprise about 1 % of all solid adult malignancies. Patient data was acquired from the University Hospital of Bonn in a single-centre analysis. The primary objectives were to evaluate the overall patient survival, recurrence rates including local control, and the prognostic factors impacting these outcomes. Importantly, this study assessed the effect of postoperative radiotherapy and its timing, as well as treatment-related adverse effects. <br /> Out of 106 patients meeting the inclusion criteria, the majority underwent sarcoma resection with negative surgical margins. Additionally, 40 patients received postoperative irradiation treatment, confirming that adjuvant radiotherapy in Europe is more prevalent compared to neoadjuvant modalities. The median time interval from surgery to the start of irradiation amounted to 48 days. The overall 5-year survival came out to 58.3 %, while the 5-year local control, including local recurrences or death, was 42.8 %, with recurrences occurring at a mean time of 16.12 months for local recurrences and 18.35 months for all recurrences. <br /> It could be shown that postoperative radiotherapy significantly improved the recurrence-free survival and local control, especially for histologically high-grade G2- and G3-rated patients, even after achieving negative surgical margins. Optimal irradiation doses were also examined, finding that higher doses exceeding 64 Gray had the same benefit and also positively impacted the overall survival of irradiated patients. Looking at wound complications, these were more likely with bigger sarcomas and impacted the timely start of adjuvant radiotherapy. While the time interval between surgery and radiotherapy did not have any significant effect on the oncological outcome, it did impact the rate of recorded radiotherapy-related adverse events. The longer the time interval between the surgery and the start of adjuvant radiotherapy, the less likely adverse events were to occur. However, the long-time adverse events including limb oedema, hardened soft tissue and joint stiffness, occurred at a lower rate in this study compared to literature. <br /> This study necessitates further research into the by the German guidelines recommended three to six weeks between surgery and the start of adjuvant radiotherapy. The definite need for diligent follow-up appointments was underscored in order to facilitate early recurrence detection in addition to close monitoring of high-risk patients. Importantly, the findings reinforce the importance of adjuvant radiotherapy as a treatment component for high-grade soft-tissue extremity sarcomas by demonstrating its efficacy in improving oncological outcomes.