S978
Clinical - Oligometastatic cancer
ESTRO 2026
Approach for Standardized Uptake Value Calculation (arXiv preprint arXiv:2410.13348). https://doi.org/10.48550/arXiv.2410 .13348 Keywords: OMD, Longitudinal FDG-PET/CT Biomarkers, NSCLC
Purpose/Objective: Stereotactic body radiotherapy (SBRT) represents the predominant metastasis-directed local treatment modality in oligometastatic cancer trials, with historical local control rates above 90%. This interim analysis of the OligoCare cohort aimed to identify disease and treatment characteristics associated with in-field progression across the included primary tumor types. Material/Methods: OligoCare is a prospective observational cohort study (within the EORTC & ESTRO E2-RADIatE platform) enrolling patients with oligometastatic prostate, breast, colorectal or non-small cell lung cancer (NSCLC) treated with radical-intent SBRT. Local progression was defined as recurrence within the planning target volume (PTV) from radiotherapy start. Death without progression served as a competing risk. Analyses were performed at both lesion and patient levels (single-lesion cohort). Statistical significance was set at α =0.025 for this exploratory analysis. Results: Between July 2019-July 2025, 57 international institutions enrolled 2,805 patients; 2,447 were eligible for analysis. Median follow-up: 31 months. Primary tumours: prostate cancer 41.7% (n=1021), NSCLC 21.7% (n=530), colorectal cancer 21.2% (n=518), breast cancer 15.4% (n=378). Median number of SBRT fractions was 5, median CTV doses per fraction varied by primaries: colorectal 12.1 Gy, NSCLC 10.6 Gy, breast 9.0 Gy, prostate 8.3 Gy. Concomitant systemic therapy was administered in 35.7% (n=874).One-year and 3- year cumulative incidence of local progression was 5.0% and 11.4%, respectively. In single-lesion patients (n=1714), multivariate analysis showed a significant association of higher PTV minimum dose with improved local control (HR 0.89 per 10Gy EQD2 increase, 97.5% CI 0.82-0.98, p=0.005). Across all patients, repeat oligometastatic disease was associated with inferior local control versus de novo oligometastases (HR1.53, 97.5% CI 1.10-2.15, p=0.004) and colorectal primary was associated with increased risk of progression compared to prostate cancer (HR 2.63, 97.5% CI 1.71-4.05, p<0.001).
Proffered Paper 2986
Clinical and treatment characteristics associated with local control following SBRT: interim analysis of ESTRO EORTC E2-RADIatE OligoCare cohort Umberto Ricardi 1 , Marta Scorsetti 2 , Filippo Alongi 3 , Daniela Greto 4 , Pètra Braam 5 , Inga-Malin Simek 6 , Ajra E Secerov 7 , Yolande Lievens 8 , Barbara Jereczek-Fossa 9 , Piet Dirix 10 , Karin Stellamans 11 , Sara Ramella 12 , Heike Peulen 13 , Gemma Sancho-Pardo 14 , Juan R Salinas 15 , Igor Sirak 16 , Paul Jeene 17 , Samuel Bral 18 , Sergi Benavente 19 , Hossein Hemmatazad 20 , Lore Meelberghs 21 , Enrico Clementel 21 , Felix Oppong 21 , Matthias Guckenberger 22 , Piet Ost 23 1 Oncology, University of Turin, Turin, Italy. 2 Department of Radiotherapy and Radiosurgery, IRCCS Humanitas Research Hospital, Rozzano (Milano), Italy. 3 IRCCS Sacro Cuore Don Calabria Hospital, University of Brescia, Negrar (Verona), Italy. 4 Radiotherapy Unit, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy. 5 Radboudumc, Radboud University Medical Center, Nijmegen, Netherlands. 6 Medical University of Vienna, CCC Vienna, Vienna, Austria. 7 Division of Radiotherapy, Institute of Oncology, Ljubljana, Slovenia. 8 Ghent University Hospital, Ghent University, Ghent, Belgium. 9 Radiotherapy, Istituto Europeo Oncologia, Milan, Italy. 10 Iridium Network, Ziekenhuis aan de Stroom (ZAS), Antwerp, Belgium. 11 Radiotherapy, AZ Groeninge Kortrijk - Campus Kennedylaan, Kortrijk, Belgium. 12 Radiotherapy, Policlinico Universitario Campus Biomedico Oncology Center, Rome, Italy. 13 Radiotherapy, Catharina Ziekenhuis, Eindhoven, Netherlands. 14 Radiotherapy, Hospital de la Santa Creu Sant Pau, Barcelona, Spain. 15 Radiotherapy, Hospital General Universitario Santa Lucia, Cartagena, Spain. 16 Radiotherapy, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic. 17 Radiotherapy, Radiotherapiegroep Locatie Deventer, Deventer, Netherlands. 18 Radiotherapy, AZORG, Aalst, Belgium. 19 Oncologia, Hospital Universitari Vall d’Hebron, Barcelona, Spain. 20 Radiation Oncology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland. 21 EORTC, The European Organisation for Research and Treatment of Cancer (EORTC) Headquarters, Brussels, Belgium. 22 Radiation Oncology, UniversitaetsSpital Zurich, Zurich, Switzerland. 23 Radiation Oncology, Universitair Ziekenhuis Gent, Gent, Belgium
Conclusion: This large multinational cohort demonstrates SBRT
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