S882
Clinical - Mixed sites & palliation
ESTRO 2026
Purpose/Objective: Reirradiation for brain metastases (BM) remains a clinical challenge due to concerns about cumulative toxicity and treatment efficacy. With advancements in stereotactic radiotherapy (SRT), reirradiation has become a viable strategy for selected patients. We report our institutional experience on salvage SRT for previously irradiated BM, focusing on survival outcomes, local control (LC), and safety. Material/Methods: Between 01/2018 and 09/2024, 188 BM in 45 patients underwent stereotactic reirradiation at our institution. All patients received previous radiotherapy, including whole-brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), or adjuvant radiotherapy post- surgical resection. Previous treatment was delivered with Gamma Knife® Radiosurgery (Elekta, Sweden, GK), CyberKnife® (Accuray, Sunnyvale, CA, USA, CK) or Tomotherapy® (Accuray, Madison, WI, USA,TT). Prescribed dose changed depending on lesion size, prior radiation dose, and proximity to critical structures. Median prescribed dose was 25 Gy (16- 37.5) in a median of 5 fractions (1-5). Median time from first radiotherapy to reirradiation was 14.6 months (2.1–54.1). Local relapse-free survival (LRFS), intracranial relapse-free survival (IRFS), and overall survival (OS) were analyzed using Kaplan-Meier estimates. Cox proportional hazards models were used to identify predictors of LC, OS, and radionecrosis. Results: Median OS was 9 months (0.7-54.4). Median LRFS was 7 months (3-13). Median IRFS was 6 months (2–12). LRFS and IRFS at 12-months were respectively 44% and 39%. A higher biologically effective dose (BED) delivered for the first treatment was significantly associated with improved LC (HR: 0.982, 95% CI: 0.966–0.998, p=0.03). The number of metastases treated during reirradiation negatively impacted OS (HR: 1.0548, 95% CI: 1.0126–1.0989, p=0.0105). Radionecrosis was observed in 4.8% of lesions. Logistic regression analysis identified prior whole-brain radiotherapy as a significant protective factor against radionecrosis (OR: 0.45, p=0.03). No cases of grade ≥ 3 toxicity were recorded. (Fig.1)
Figure 1 Conclusion: Salvage SRT for previously irradiated BM is an effective and well-tolerated approach, achieving good local control with acceptable toxicity rates. Higher BED correlates with improved LC, while a larger number of metastases negatively affects OS. These findings support the integration of reirradiation into personalized treatment strategies for recurrent BM. Keywords: reirradiation, brain metastasis, radionecrosis Digital Poster 2413 Multidisciplinary spinal cord compression committee as a tool to improve the selection of patients eligible for surgery. A single center experience. Marc Ruiz Domínguez 1 , Héctor Pérez Montero 1 , Arturo Navarro Martín 2 , Margherita Moretti 1 , Laura Martín González 1 , Claudia Balcells Quintana 3 , Alicia Lozano Borbalás 1 , Tatiana B Pullas Mantilla 1 , Maria A Llodrà Bisellach 1 , Kevin Molina Mata 4 , Maria M Marín Melià 4 , Gemma Blanch Pujol 5 , Luis A López Obarrio 5 , Óscar Godino Martínez 6 , Isabel Linares Galiana 1 , Roser Margarit Cuadros 7 , Esmeralda Fernández Mariscal 7 , Javier Hernández Gañán 8 , Iago Arribas Castro 9 , Itziar Carro Arrostegui 9 , Maria Aranzazu Eraso Urien 1 , Laura Martínez Ávila 10 , Yuanyuan L Lin 10 1 Radiation Oncology, Institut Català d’Oncologia, Barcelona, Spain. 2 Radiation Oncology, Hospital Clínic, Barcelona, Spain. 3 Radiation Oncology, Institut Català d’Oncologia ilinares, Barcelona, Spain. 4 Medical Oncology, Institut Català d’Oncologia, Barcelona, Spain. 5 Neurosurgery, Bellvitge Hospital University, Barcelona, Spain. 6 Neurosurgery, Hospital Quirón, Barcelona, Spain. 7 Palliative Care, Institut Català d’Oncologia, Barcelona, Spain. 8 Radiology, Bellvitge
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