S916
Clinical - Mixed sites & palliation
ESTRO 2026
Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy. 13 Medical Oncology, Bellaria Hospital, Azienda USL Bologna, Bologna, Italy Purpose/Objective: Outcomes of patients with brain metastases are significantly improving.1 Therefore, frequency of detection of brain metastases local recurrence/progression is increasing, posing significant challenges in clinical practice. Salvage reirradiation with SRT could be considered for patients experiencing local failures after prior SRT.2-3 In this context, an interdisciplinary evaluation and a thorough selection of patients is essential.1 Material/Methods: In this monocentric retrospective study, patients treated with local salvage reirradiation (SRT2) after prior SRT (SRT1) for recurrent/progressive brain metastases, from January 2020 to August 2025, were enrolled. Intracranial disease status was evaluated by functional MRI and/or PET-CT scan 11C-Methionine. Multidisciplinary evaluation was performed to differentiate between radiological changes from previous treatments and local recurrent/progressive disease, and to select patients for local reirradiation. Results: A cohort of 12 patients, for a total of 15 reirradiated lesions, with a median age of 66 years and mixed primary tumor histology, was evaluated. Median time to local recurrence after SRT1 was 18 months (6 – 32), and median time to local reirradiation was 20 months (8 – 33). Any of the 15 retreated lesions received surgery before SRT2, and all patients had stable extracranial disease. At SRT2, median KPS was 90 (80- 100). Median PTV volume was 4.42 cc (2.10-24.74), median PTV Dmin was 24.1 Gy(20.20 - 27.84 cc) median PTV Dmax was 32.06 Gy (28.26 - 37.80 cc). A median total dose of 25 Gy (24 – 30), with a median fraction dose of 5 Gy (5 – 8), was prescribed at a median isodose line of 80% (77.8 - 82.9), for a median PTV coverage of 98.6% (95 - 99.9). Seven patients received concomitant systemic therapy. At a median F- UP of 10 months (2 - 65), the crude local control (LC), intracranial distant recurrence and extracranial recurrence rates, were 80%,66.6% and 41.6%, respectively. The 1y-LC was 65%. Median OS was 15,9 months (95% CI, 4,3 - 27,4), with a 1y-OS of 61%. Median time to radiological radionecrosis was 3 months (2 - 16): nine patients (60%) had radiological changes (functional MRI and/or MET-PET) suggestive of radionecrosis, without any correlated neurological deficits (CTCAE v5.0 Grade 1). Conclusion: Salvage reirradiation with SRT for local
Conclusion: Re-RT for bone metastases is safe and effective, providing significant local control and symptom relief with minimal severe toxicity. Key factors influencing outcomes include cumulative dose, treatment interval, and tumor histology (particularly breast and genitourinary cancers), supporting its role in bone metastases management. Keywords: re-RT bone metastases Stereotactic radiotherapy (SRT) for local retreatment of recurrent/progressive brain metastases after prior SRT: a monocentric feasibility experience Barbara Diletto 1 , Damiano Balestrini 1 , Vania Ramponi 2 , Silvia Ricci 3 , Raffaella Romagnoli 3 , Alicia Tosoni 4 , Donato Fiorenzo 5 , Stella Battaglia 5 , Sofia Asioli 6,7 , Barbara Melotti 8 , Alessandra Musto 9 , Paola Berardi 3 , Stefano Fanti 9,10 , Maria Pia Foschini 6,11 , Andrea Ardizzoni 8,12 , Antonio Maestri 13 , Alfredo Conti 2,6 , Enrico Franceschi 4 , Elisa D' Angelo 1 Digital Poster 4393 1 Radiation Oncology, Bellaria Hospital, Azienda USL Bologna, Bologna, Italy. 2 Neurosurgery, Bellaria Hospital, IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy. 3 Medical Physics, Bellaria Hospital, Azienda USL Bologna, Bologna, Italy. 4 Nervous System Medical Oncology, Bellaria Hospital, IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy. 5 Neuroradiology, Bellaria Hospital, IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy. 6 Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy. 7 Anatomic Pathology, Bellaria Hospital, IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy. 8 Medical Oncology, IRCCS, Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy. 9 Nuclear Medicine, IRCCS, Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy. 10 Nuclear Medicine, University of Bologna, Bologna, Italy. 11 Anatomic Pathology, Bellaria Hospital, Bologna, Italy. 12 Medical Oncology,
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