S1284
Clinical - Urology
ESTRO 2026
Australia. 6 Sir Peter MacCallum dep of Oncology, University of Melbourne, Melbourne, Australia
Purpose/Objective: Biochemical recurrence (BCR) after radiotherapy occurs in up to 30% of prostate cancer patients. The Phoenix definition (PSA rise ≥ 2 ng/ml) may delay diagnosis, while conventional imaging lacks sensitivity at low PSA. Prostate-specific membrane antigen positron emission tomography–computed tomography (PSMA PET–CT) offers superior accuracy. We aimed to evaluate its detection efficacy and ability to localise recurrence in men with BCR after radiotherapy Material/Methods: A systematic review was performed according to PRISMA guidelines (PROSPERO: CRD42022315968). Ovid MEDLINE, Embase, and the Cochrane Library were searched to September 2025. Eligible studies included men with rising PSA following external beam radiotherapy or brachytherapy who underwent PSMA PET–CT. Data were pooled using a random-effects model. Subgroup analysis was performed by PSA level. Study quality was assessed with QUADAS-2 Results:
Twenty-one studies (n=2925) were included. The pooled detection rate of PSMA PET–CT for recurrence after radiotherapy was 90%(95% confidence interval [CI] 87–91%). At PSA <2 ng/ml, detection remained high at 77% (95% CI 72–81%). Pooled localisation analysis showed recurrence confined to the prostate or pelvic nodes in 54% (95% CI 49–60%) and distant metastases in 46% (95%CI 41–52%). Among men with PSA <2 ng/ml (n=320), 72% had locoregional recurrence and 28% had distant disease. Risk of bias was mainly related to reference standard limitations. Conclusion: PSMA PET–CT shows high accuracy for detecting recurrent prostate cancer after radiotherapy, including at PSA levels below the Phoenix threshold. Its ability to distinguish locoregional from distant disease supports personalised salvage strategies and highlights the limitations of the Phoenix definition in the PSMA era. Keywords: Prostate cancer, Radiotherapy, PSMA-PET Australia and New Zealand bi-national survey on prostate SABR re-irradiation: who, when, and how? Therese Kang 1,2 , Shreya Armstrong 3 , Sarat Chander 4 , Jeremy De Leon 5 , Renee Finnigan 6 , Suki Gill 7 , Mario Guerrieri 8 , Amy Hayden 9 , Braden Higgs 10 , Tanya Holt 11 , Michael Jones 12 , Yuan Hong Lin 4 , Giuseppe Sasso 13 , Neetu Tejani 4 , Wee Loon Ong 1,2 1 Radiation Oncology, Alfred Health, Monash University, Melbourne, Australia. 2 Radiation Oncology, Andrew Love Cancer Centre, Barwon Health, Geelong, Australia. 3 Department of Radiation Oncology, North Coast Cancer Institute, Lismore, Australia. 4 Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia. 5 Radiation Oncology, Genesis Care, Darlinghurst, Australia. 6 Radiation Oncology, ICON Gold Coast University Hospital, Southport, Australia. 7 Radiation Oncology, Sir Charles Gairdner Digital Poster 3970
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