Search

Background and Purpose: The SOFT trial is a prospective, multicenter, phase 2 trial investigating magnetic resonance (MR)-guided stereotactic ablative radiotherapy (SABR) for abdominal, soft tissue metastases in patients with oligometastatic disease (OMD) (clinicaltrials.gov ID NCT04407897). We present the primary endpoint analysis of 1-year treatment-related toxicity (TRAE)., Materials and Methods: Patients with up to five oligometastases from non-hematological cancers were eligible for inclusion. A risk-adapted strategy prioritized fixed organs at risk (OAR) constraints over target coverage. Fractionation schemes were 45-67.5 Gy in 3-8 fractions. The primary endpoint was grade ≥ 4 TRAE within 12 months post-SABR. The association between the risk of gastrointestinal (GI) toxicity and clinical and dosimetric parameters was tested using a normal tissue complication probability model., Results: We included 121 patients with 147 oligometastatic targets, mainly located in the liver (41 %), lymph nodes (35 %), or adrenal glands (14 %). Nearly half of all targets (48 %, n = 71) were within 10 mm of a radiosensitive OAR. No grade 4 or 5 TRAEs, 3.5 % grade 3 TRAEs, and 43.7 % grade 2 TRAEs were reported within the first year of follow-up. We found a significant association between grade ≥ 2 GI toxicity and the parameters GI OAR D 0.1cc, D 1cc, and D 20cc ., Conclusion: In this phase II study of MR-guided SABR of oligometastases in the infra-diaphragmatic region, we found a low incidence of toxicity despite half of the lesions being within 10 mm of a radiosensitive OAR. GI OAR D 0.1cc, D 1cc, and D 20cc were associated with grade ≥ 2 GI toxicity., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: MF has received research grant from Varian Medical Systems and support from The Danish National Research Centre for Radiotherapy and the Danish Cancer Society. CPB reports institutional research contracts with Brainlab, Varian Medical Systems, Siemens, and ViewRay and teaching contracts with Varian Medical Systems. Research funding from Danish Comprehensive Cancer Center National Thematic Center on radiotherapy (DCCC-RT). UB reports institutional research contracts with Elekta. IVR reports institutional research contracts with Brainlab, Varian Medical Systems, and ViewRay and teaching contracts with Varian Medical Systems. GP has received research grants from Varian Medical Systems, The Danish National Research Centre for Radiotherapy, and the Danish Cancer Society, Herlev & Gentofte Hospitals Internal Research Council, Villadsens Family Foundation. Conference participance from MSD, Daiichi Sankyo, and Pfizer, Pierre Fabre and honoraria for consultancies and lectures from Astra Zeneca. PP has received research grant from Viewray; not relevant to this article; Stock ownership of Nuvaira (COPD device company). MJ have received research support from The Danish National Research Centre for Radiotherapy and the Danish Cancer Society. MP have received honoraria for lectures from Astra Zeneca, BMS, MSD, Pfizer, Roche, Amgen. TS have received honoraria for lectures and travel expenses from Elekta and declares travel assistance from ELEKTA and is member of the MR-L consortium. SB have received research support from The Danish National Research Centre for Radiotherapy. PG reports institutional research contracts with Viewray. PK, ESH, and KJ has nothing to disclose., (Copyright © 2024 Elsevier B.V. All rights reserved.)