S1286
Clinical - Urology
ESTRO 2026
Oncology, University of Western Australia, Western Australia, Australia. 10 GenesisCare, Western Private Hospital, Footscray, Australia. 11 Sydney West Radiation Oncology Network, Western Sydney Local Health District, New South Wales, Australia. 12 Radiation Oncology, Western Sydney University, Sydney, Australia. 13 Department of Radiation Oncology, Royal Adelaide Hospital, South Australia, Australia. 14 Radiation Oncology, University of South Australia, Adelaide, Australia. 15 Radiation Oncology, Princess Alexandra Hospital Raymond Terrace, Brisbane, Australia. 16 Radiation Oncology, The University of Queensland, Brisbane, Australia. 17 Department of Radiation Oncology, Royal Hobart Hospital, Hobart, Australia. 18 Radiation Oncology, University of Tasmania, Hobart, Australia. 19 Radiation Oncology Services, Auckland and Dunedin Hospitals, Health New Zealand, Te Whatu Ora, New Zealand. 20 Department of Oncology, School of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand. 21 Department of Radiation Oncology, Tata Memorial Hospital and Advanced Centre for Treatment Research and Education in Cancer (ACTRECT), Homi Bhabha National Institute, Homi Bhabha National Institute, India. 22 Department of Radiation Oncology, Sunnybrook Odette Cancer Centre, University of Toronto, Toronto, Canada. 23 Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada Purpose/Objective: Prostate SABR is now a standard of care radiotherapy option for prostate cancer based on high-level clinical trial evidence. As part of the Australia and New Zealand (ANZ) prostate SABR guideline development process, Royal Australia and New Zealand College of Radiologist (RANZCR) has commissioned a pattern of practice survey on contemporaneous prostate SABR practice. Material/Methods: This is a cross-sectional survey among ANZ genitourinary radiation oncologists (ROs), focusing on patient selection, contouring, treatment planning and delivery for prostate SABR. Results: A total of 53 ROs across ANZ responded to the survey (response rate 28%). Of the 41 ROs currently offering prostate SABR, 95%, 90%, 35% and 5% offers prostate SABR as standard of care option to individuals with favourable intermediate risk, unfavourable intermediate risk, favourable high risk (NINJA trial- eligible), and very high risk prostate cancer, respectively. Most ROs (86%) routinely use fiducial markers and approximately half (54%) routinely use a rectal spacer. All ROs routinely request planning MRI for contouring. The CTV contouring ranged from prostate alone (26%) to prostate plus proximal 1cm of
fraction in 17 (22.4%) patients, with a concomitant boost to the prostate ³ 40 Gy in the remaining 59 (77.6%). Median antero-posterior separation between prostate and rectum at the level of the mid-gland created by HRS was 10 mm (range 4-20 mm). SQS score was defined as 0 (“inadequate”), 1 (“good”), and 2 (“excellent”) in 3 (3.9%), 48 (63.2%), and 25 (32.9%) patients, respectively. SQS score was associated with rectal Dmax (p = 0.003), maximum dose to 1 cc (p = 0.003), V36 (p = 0.018), V30 (p = 0.002), and V18 (p = 0.002). SYM score was 1 (“best”), 2, 3, 4, and 5 (“worst”) in 52 (68.4%), 17 (22.4%), 2 (2.6%), 3 (4.0%), and 2 (2.6%) cases, respectively. SYM score was associated with rectal V40 (p = 0.009). RWI score was 0 (no abnormality), 1 (rectal wall edema), 2 (superficial RWI), and 3 (deep RWI) in 56 (73.7%), 2 (2.6%), 18 (23.7%) and 0 (0%) patients, respectively. Acute rectal side effects occurred in 18 (23.7%) patients, with 3 (16.7%) G1 and 15 (83.3%) G2 cases, respectively. Acute rectal side effects incidence was associated with SQS score (p = 0.004), while no correlation with RWI categories was detected (p = 0.672). Conclusion: In this study, a high-quality HRS distribution was associated with improved rectal dosimetry and reduced acute adverse events in patients treated with SBRT for localized prostate cancer. RWI was observed in a quarter of patients but was not associated with acute rectal side effects. Keywords: Prostate, Radiotherapy, Stereotactic From clinical trials to clinical practice – patterns of practice survey of prostate SABR in Australia and New Zealand Therese Kang 1,2 , Shreya Armstrong 3 , Sarat Chander 4,5 , Jeremy de Leon 6 , Renee Finnigan 7 , Suki Gill 8,9 , Mario Guerrieri 10 , Amy Hayden 11,12 , Braden Higgs 13,14 , Tanya Holt 15,16 , Michael Jones 17,18 , Yuan-Hong Lin 4 , Giuseppe Sasso 19,20 , Neetu Tejani 4,5 , Vedang Murthy 21 , Andrew Loblaw 22,23 , Wee Loon Ong 1,2 1 Alfred Health Radiation Oncology, School of Translational Medicine, Monash University, Melbourne, Australia. 2 Department of Radiation Oncology, Andrew Love Cancer Centre, Barwon Health, Geelong, Australia. 3 Department of Radiation Oncology, North Coast Cancer Institute, Lismore, Australia. 4 Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia. 5 Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia. 6 Radiation Oncology, Genesiscare, Melbourne, Australia. 7 ICON, Gold Coast University Hospital, Southport, Australia. 8 Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Australia. 9 Radiation Digital Poster 3995
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