S963
Clinical - Oligometastatic cancer
ESTRO 2026
In total, 39% of respondents would enroll patients with 1-2 oligoprogressing lesions in a clinical trial randomizing between SABR and no radiotherapy. This increased to 60% for patients with 3-5 oligoprogressing lesions randomized between SABR and no radiotherapy, and to 57% for patients with 1-5 oligoprogressing lesions randomized between SABR and conventional palliative radiotherapy.
Digital Poster Highlight 202
An international survey on practice patterns on the use of stereotactic ablative radiotherapy for oligoprogressive cancers Emily O'Reilly 1 , David Palma 2 , Robert Olson 3 , Devin Schellenberg 4 , Anand Swaminath 5 , Jonas Willmann 6 , Nicolaus Andratschke 6 , Stephanie Tanadini-Lang 6 , Marta Scorsetti 7 , Mattias Guckenberger 6 , Sarah Baker 4 1 Radiation Oncology, BC Cancer, Vancouver, Canada. 2 Radiation Oncology, London Health Sciences Centre, London, Canada. 3 Radiation Oncology, BC Cancer, Prince George, Canada. 4 Radiation Oncology, BC Cancer, Surrey, Canada. 5 Radiation Oncology, Juravinski Cancer Centre, Hamilton, Canada. 6 Radiation Oncology, University Hospital Zurich, Zurich, Switzerland. 7 Radiation Oncology, Humanitas Clinical and Research Center, Milan, Italy Purpose/Objective: Over the past two decades, there has been increasing utilization of metastasis directed therapy (MDT) including stereotactic ablative radiotherapy (SABR) for oligometastatic cancer. However, there is limited prospective data to support MDT in the setting of oligoprogression. This study aimed to determine international patterns of practice and equipoise in the use SABR for oligoprogressive cancer. Material/Methods: A survey was conducted among international SABR radiation oncologists from December 2023 to June 2024 assessing the use of SABR for oligoprogression in routine practice and potential clinical trials. The survey was distributed across multiple radiation oncology societies and social media platforms. Results: The survey was completed by 241 radiation oncologists across 40 countries (Figure 1). A total of 90% of respondents viewed SABR as a standard-of- care treatment option for select patients with oligoprogression. However, application of SABR varied by primary tumor histology (p<0.001) and only 34% of respondents offered SABR to all primary tumour types outside of a clinical trial setting (Figure 2). The most common rationale for offering SABR off-trial was to provide local control, followed by delaying next line systemic therapy. The majority of respondents (71%) reported no specific patient selection criteria at their institution. Most respondents considered 3 or 5 progressing lesions the maximum number for which patients should be eligible for SABR (44% and 34%, respectively). Dose prescription was variable, with 89 different SABR regimens reported, however, most utilized BED10 > 100 Gy for peripheral lung, central lung, and liver (91%, 78% and 71%, respectively) and BED10 < 100 Gy for lymph node, spine, non-spine bone and adrenal (4%, 1%, 1% and 18%, respectively).
Conclusion: There is a high level of acceptance of SABR internationally as a routine treatment option for select patients with oligoprogressive cancer, though the selection criteria varied by respondent. Variability in dose prescription and patient selection highlights the need for further data to guide optimal practice. Enthusiasm for participation in randomized clinical trials varies by control arm and patient population, and these results may inform subsequent clinical trial design. Keywords: Oligoprogression, SABR, Survey Radiotherapy (SABR) on systemic therapy for oligometastatic cancer: Real-World Multicentre Experience Elena Moreno-Olmedo 1 , Veni Ezhil 2 , Kevin Frank 3 , Andy Gaya 4 , John Conibear 4 , Crispin Hiley 4 , Kasia Owczarczyk 4 , James Good 1 , David Woolf 5 1 Stereotactic and MR-Linac Radiotherapy Department, GenesisCare UK, Oxford, United Kingdom. 2 Stereotactic and MR-Linac Radiotherapy Department, GenesisCare UK, Oxford/London, United Kingdom. Digital Poster 457 Integrating Stereotactic Ablative Body
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