S968
Clinical - Oligometastatic cancer
ESTRO 2026
radical intent in oligometastatic patients treated in routine clinical practice. Material/Methods: This multicentre, retrospective, observational study included oligometastatic patients treated with SBRT between 2020 and 2024 across 13 Spanish radiotherapy centres. Eligible patients were aged ≥ 18 years, with all newly diagnosed or progressive metastases amenable to radical-intent SBRT. Patients with uncontrolled brain metastases or re-irradiations were excluded.The primary endpoint was 1-year progression-free survival (PFS). Secondary endpoints included overall survival (OS), local control, and acute and late toxicity. Subgroup analyses were performed by primary tumour histology, oligometastatic subtype (synchronous, metachronous, repeat, or induced [previously polymetastatic]), and metastasis location. Results: A total of 300 patients and 452 lesions were treated with SBRT. The median age was 69 years. Primary tumour included prostate (n=94), colorectal (n=55), lung (n=47), breast (n=31), and others (n=71). The most frequent oligometastatic subtype was metachronous (43%), followed by repeat (27.3%), induced (17.3%), and synchronous (12.3%). Metastatic sites comprised visceral (n=122), bone (n=109), lymph node (n=33), and mixed locations (n=36).After a median follow-up of 22 months, the 1-year PFS rate was 45.1%, with a median PFS of 11 months (95% CI 9–13). The 1-year OS rate was 92% and median OS was not reached. One-year local control was 88.2%. Tumour histology significantly correlated with PFS and OS, with the best outcomes in prostate cancer. Patients with repeat or induced oligometastatic disease showed worse PFS than those with synchronous disease (HR 3.54, 95% CI 2.04–6.15; p<0.001; HR 4.41, 95% CI 2.46–7.88; p<0.001), while no difference was observed between synchronous and metachronous subtypes. PFS was also poorer in patients with visceral metastases or mixed locations than in those with bone-only lesions (HR 2.25, 95% CI 1.45–2.82; p<0.001; HR 2.51, 95% CI 1.6–3.92; p<0.001). Local control was significantly lower for metastases ≥ 5 cm than <5 cm (p<0.001).Treatment was well tolerated. Grade ≥ 2 acute and late toxicity occurred in 11 (3.7%) and 8 patients (2.7%) respectively.
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Stereotactic body radiotherapy for oligometastatic disease: a national multicentre real-world study Macarena Teja 1,2 , María González 1,2 , M. Isabel Garrido 3 , David Esteban 4 , Lisselott Torres 1,2 , Fernando López Campos 5,2 , Álvaro Pinto 6,7 , Abrahams Ocanto 1,2 , Castalia Fernández 1,2 , Daniela Gonsalves 1,2 , Escarlata López 8,9 , Jaume Fernández 10 , Loubna Aakki 11 , Antonio Ristori 12 , Sigfredo E Romero Zoghbi 13 , Jon Andreescu 14 , Ana B Bezares 15 , María Mateos 16 , Evita Krumina 17 , José Begara 18 , Daniel Rivas 8 , José A. González Ferreira 19 , Luis A. Glaría 20,1 , Miren Gaztañaga 21,2 , Felipe Couñago 22,23 1 Radiation Oncology, San Francisco de Asís University Hospital, Madrid, Spain. 2 Radiation Oncology, Vithas La Milagrosa University Hospital, Madrid, Spain. 3 Radiation Oncology, Centro de Protonterapia Quirónsalud, Madrid, Spain. 4 Radiation Oncology, GenesisCare Alcázar de San Juan, Alcázar de San Juan, Spain. 5 Radiation Oncology, Ramón y Cajal University Hospital, Madrid, Spain. 6 Coordinator of the Urologic Oncology Unit - Medical Oncology Department, La Paz University Hospital, Madrid, Spain. 7 Translational Oncology Unit - Institute of Research IdiPAZ, La Paz University Hospital - IdiPAZ, Madrid, Spain. 8 Radiation Oncology, GenesisCare Málaga, Málaga, Spain. 9 Radiation Oncology, GenesisCare Granada, Granada, Spain. 10 Radiation Oncology, Centro 360 de Excelencia Oncológica GCCC, Barcelona, Spain. 11 Radiation Oncology, GenesisCare Alicante, Alicante, Spain. 12 Radiation Oncology, GenesisCare Jerez de la Frontera, Jerez de la Frontera, Spain. 13 Radiation Oncology, GenesisCare Talavera de la Reina, Talavera de la Reina, Spain. 14 Radiation Oncology, GenesisCare Córdoba, Córdoba, Spain. 15 Radiation Oncology, GenesisCare Campo de Gibraltar, Algeciras, Spain. 16 Radiation Oncology, Torrejón University Hospital, Torrejón de Ardoz, Spain. 17 Radiation Oncology, GenesisCare Guadalajara, Guadalajara, Spain. 18 Radiation Oncology, Centro Andaluz de Excelencia en Radiocirugía, Málaga, Spain. 19 Radiation Oncology, GenesisCare Sevilla, Sevilla, Spain. 20 Radiation Oncology, La Paz University Hospital, Madrid, Spain. 21 Radiation Oncology, Clínico San Carlos University Hospital, Madrid, Spain. 22 National Director, GenesisCare Spain, Madrid, Spain. 23 Department of Medicine, School of Medicine, Health and Sport, European University of Madrid, Madrid, Spain Purpose/Objective: Stereotactic body radiotherapy (SBRT) has shown high rates of local control and potential survival benefits in oligometastatic patients. However, evidence from large real-world studies with long-term follow-up are scarce. We conducted the first multicentre Spanish study assessing the efficacy and safety of SBRT with
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