ESTRO 2023 - Abstract Book

S1304

Digital Posters

ESTRO 2023

PO-1607 Same-day MRI-LINAC guided single fraction radiosurgery for painful non-spine bone metastases

E. Kretschmer 1 , M. Mayinger 1 , M. Chamberlain 2 , N. Weitkamp 1 , S. Ehrbar 1 , M. Bogowicz 1 , L. Wilke 1 , S. Tanadini-Lang 1 , N. Andratschke 1 , M. Guckenberger 1 , H. Garcia 1 1 Universitätsspital Zürich, Klinik für Radio-Onkologie, Zürich, Switzerland; 2 Universitätsspital Zürich, Klinik für Radio Onkologie, Zürich, Germany Purpose or Objective Recent data indicated improved efficacy of high-dose single-fraction stereotactic body radiotherapy (SBRT) for painful bone metastases. The aim of this study was to assess the feasibility of a same-day-workflow with MR-only planning and delivery in a single radiosurgical session without previous simulation, aiming to provide rapid pain relief. Materials and Methods This prospective aquired, single-institution study enrolled patients with radiologically confirmed painful bone metastases with pain scores ≥ 3 / 10 (on 0 to 10 numeric rating scale= NRS). Patients received single-fraction SBRT with 12 Gy at an MR-Linac (ViewRay) with same-day planning and delivery of radiosurgery. We analyzed the procedure regarding process times, pain response, and treatment tolerance. Results 15 patients were enrolled from June 2019 until January 2022 and 17 lesions have been irradiated. Mean age 63 years (range 30- 87 y). Mean GTV was 26.0 ccm, median was 15.6 ccm (range 1.1 to 84.4 ccm). Same-day SBRT planning and delivery was feasible and successfully performed in all patients. Median on-table time for contouring, SBRT planning and delivery was 65 minutes (range 57 – 112). No treatment interruption was observed. Median pre-treatment pain score was 6 points which was reduced to median NRS 0 (P=0.0028) at the 4-weeks follow-up. None of the patients developed a pain flare. No grade 3 or 4 toxicities were observed. Conclusion Same-day MR-guided SBRT planning and delivery for painful bone metastases was feasible and achieved promising pain response. Future prospective trials investigating this intervention are warranted, especially in palliative patients with a need for rapid pain response to improve quality of life. A. Gorza 1,3 , G. Fanetti 2 , V. Baggio 1 , I. Turturici 2 , O. Servodio 4 , A. Revelant 2 , F. Gessoni 2,3 , A.F.S. Minissale 1 , F. Matrone 2 , F. Bertini 2 , A. Donofrio 2 , M. Moro 5 , P. Chiovati 6 , F. Ferrarese 1 , M. Mascarin 2 1 AULSS 2 Marca Trevigiana, Treviso Hospital, Division of Radiation Oncology, Treviso, Italy; 2 Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, Division of Radiation Oncology, Aviano, Italy; 3 University of Padua, Department of Medicine DIMED, Padua, Italy; 4 AULSS 2 Marca Trevigiana, Treviso Hospital, Division of Radiation Oncology, Aviano, Italy; 5 AULSS 2 Marca Trevigiana, Treviso Hospital, Division of Neurosurgery, Treviso, Italy; 6 Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, Division of Medical Physics, Aviano, Italy Purpose or Objective To evaluate the oncologic outcome, toxicity and prognostic factors associated with outcome of the combined treatment with Immune Checkpoint Inhibitors (ICIs) and Stereotactic Radiotherapy (SRT) in patients with metastatic disease from different primary malignancies. Materials and Methods A retrospective multicenter cohort of metastatic patients treated with ICIs and SRT for oligometastatic (OMD) or oligoprogressive disease (OPD) was performed. Descriptive statistics was used to evaluate patient and treatment related features. Progression-Free Survival (PFS), Overall Survival (OS) and Therapy switch-Free Survival (TS-FS) were analyzed PO-1608 Synergistic effect of stereotactic radiotherapy and immunotherapy: an italian multicentric study