Neoadjuvant irradiation of extremity soft tissue sarcoma with ions (Extrem-ion): study protocol for a randomized phase II pilot trial

• Published in: BMC cancer 2022-05, Vol.22 (1), p.538-8, Article 538
• Main Authors: Brügemann, D, Lehner, B, Kieser, M, Krisam, J, Hommertgen, A, Jaekel, C, Harrabi, S B, Herfarth, K, Mechtesheimer, G, Sedlaczek, O, Egerer, G, Geisbüsch, A, Uhl, M, Debus, J, Seidensaal, K
• Format: Article
• Language: English
• Subjects: Amputation; Carbon; Carbon - therapeutic use; Carbon ion therapy; Care and treatment; Clinical trials; Clinical Trials, Phase II as Topic; Consent; Edema; Extremities; Extremity soft tissue sarcoma; Fibrosis; Health aspects; Humans; Hypofractionation; Ions; Ions - therapeutic use; Irradiation; Neoadjuvant therapy; Neoadjuvant Therapy - adverse effects; Patients; Pilot Projects; Prospective Studies; Proton therapy; Protons; Quality of Life; Radiation therapy; Radiotherapy; Randomized Controlled Trials as Topic; Randomized trial; Sarcoma; Sarcoma - drug therapy; Sarcoma - radiotherapy; Sarcoma - surgery; Soft Tissue Neoplasms - drug therapy; Soft tissue sarcoma; Study Protocol; Surgery; Survival; Testing; Toxicity; Tumors; Wound healing
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/s12885-022-09560-x

The standard of care treatment for soft tissue sarcoma of the extremities is a wide resection in combination with pre- or postoperative radiotherapy with high local control rates, sparing patients the necessity of amputation without compromising on overall survival rates. The currently preferred timing of radiotherapy is under debate. Albeit having higher rates of acute wound complications, late side effects like fibrosis, joint stiffness or edema are less frequent in preoperative compared to postoperative radiotherapy. This can be explained in smaller treatment volumes and a lower dose in the preoperative setting. Particles allow better sparing of surrounding tissues at risk, and carbon ions additionally offer biologic advantages and are preferred in less radiosensitive tumors. Hypofractionation allows for a significantly shorter treatment duration. Extrem-ion is a prospective, randomized, monocentric phase II trial. Patients with resectable or marginally resectable, histologically confirmed soft tissue sarcoma of the extremities will be randomized between neoadjuvant proton or neoadjuvant carbon ion radiotherapy in active scanning beam application technique (39 Gy [relative biological effectiveness, RBE] in 13 fractions [5-6 fractions per week] in each arm). The primary objective is the proportion of therapies without wound healing disorder the first 120 days after surgery or discontinuation of treatment for any reason related to the treatment. The secondary endpoints of the study consist of local control, local progression-free survival, disease-free survival, overall survival, and quality of life. The aim of this study is to confirm that hypofractionated, preoperative radiotherapy is safe and feasible. The potential for reduced toxicity by the utilization of particle therapy is the rational of this trial. A subsequent randomized phase III trial will compare the hypofractionated proton and carbon ion irradiation in regards to local control. ClinicalTrials.gov Identifier: NCT04946357 ; Retrospectively registered June 30, 2021.