ESTRO 2025 - Abstract Book

S2066

Clinical - Urology

ESTRO 2025

Purpose/Objective: We present the 5 year outcomes from the SPORT trial, a randomised feasibility study comparing prostate SABR (P SABR) to prostate and pelvic lymph node SABR (PPN-SABR) in patients with unfavourable intermediate or high risk localised prostate cancer (1) . Material/Methods: 30 patients with at least one of the following were recruited: MRI stage T3aN0M0, Gleason score ≥4+3 or PSA >20ng/ml. Patients with T3b and T4 disease were excluded. 83% of patients had high risk localised prostate adenocarcinoma. Patients were randomised 1:1 to P-SABR or PPN-SABR. The PTV dose was 36.25Gy/5 fractions weekly to the prostate and proximal 1-2cm of seminal vesicles (40Gy to CTV, 5mm margin). PPN-SABR patients also received 25Gy/5 fractions to pelvic nodes. The final cohort of 10 patients received a boost to the dominant intra-prostatic lesion of up to 50Gy. The main outcome measure was freedom from biochemical and clinical failure (FBCF) at 5 years. Radiation Therapy Oncology Group (RTOG) late toxicity was recorded at 90 days to 60 months post SABR. Patient reported outcomes were collected using the Expanded Prostate Cancer Index composite quality of life questionnaire. Results: All 30 patients were followed up for 5 years or more (median follow up 64 months). 5 year FBCF was 89.7% in the overall cohort (80.0% P-SABR, 100% PPN-SABR). 3 patients in the P-SABR group had biochemical failure and 2 developed metastatic disease. No patients were lost to follow up.

At 5 years the cumulative incidence of late RTOG ≥ grade 2 genitourinary (GU) toxicity was 13.3% in the P -SABR group and 33.3% in the PPN-SABR group. 1 patient in the PPN-SABR group experienced grade 3 GU toxicity (cystitis and haematuria). RTOG ≥ grade 2 gastrointestinal (GI) toxicity occurred in 6.7% of patients in the P -SABR group and 13.3% of patients in the PPN-SABR group. No grade 3 GI toxicity was identified. There was no significant difference between groups. At 5 years 92% (23/25) of patients reported no problem/small problem with urinary function. 2 patients reported moderate or severe problems, 1 in each group. 96% (23/24) of patients reported no problem/small problem with bowel function. 1 patient who received PPN-SABR reported a moderate problem, there were no reports of severe problems.