ESTRO 2025 - Abstract Book

S2054

Clinical - Urology

ESTRO 2025

Conclusion: SABR for RCC using the Cyberknife ® system was well tolerated with acceptable acute toxicity. Initial tumour enlargement after treatment was common but long-term local disease control was achieved in 94% of patients. Stereotactic radiotherapy would appear to be a treatment option for patients not fit for surgical resection.

Keywords: Renal, Cyberknife, SABR

3511

Digital Poster External validation of Prostate Specific Antigen dynamics for prediction of biochemical recurrence with variable androgen deprivation therapy duration Jane Shortall 1 , Andrew Green 2 , Eliana Vasquez Osorio 1 , David Wong 3 , Conor McGarry 4,5 , Kimberley Reeves 1 , Ananya Choudhury 1,6 , Peter Hoskin 1,6 , Tanuj Puri 1 , Marcel van Herk 1 , Suneil Jain 4 , Alan McWilliam 1 1 Department of Cancer Sciences, The University of Manchester, Manchester, United Kingdom. 2 Bateman group, EMBL’s European Bioinformatics Institute, Cambridge, United Kingdom. 3 Health informatics and data science, University of Leeds, Leeds, United Kingdom. 4 Patrick G. Johnston Centre for Cancer Research, Queen’s University Belfast, Belfast, Ireland. 5 National Preclinical Imaging Centre, Royal College of Surgeons in Ireland, Dublin, Ireland. 6 Clinical Oncology, The Christie NHS Foundation Trust, Manchester, United Kingdom Purpose/Objective: Post-radiotherapy prostate specific antigen (PSA) dynamics have shown prognostic promise in prostate cancer. Current studies do not account for variable androgen deprivation therapy (ADT), and only include patients who have not received ADT, or only consider PSA after ADT recovery. We investigate whether PSA dynamic information can characterise risk of biochemical recurrence (BCR) in patients treated with different radiotherapy techniques and ADT duration across two independent centres. Material/Methods: Patient data, was collected for 704 mixed-risk men across two centres (training: n=244, radiotherapy or neoadjuvant ADT plus radiotherapy, validation: n=460, neoadjuvant ADT plus radiotherapy). All patients had at least two post radiotherapy PSA measurements. PSA up to and including BCR was included.