ESTRO 2025 - Abstract Book

S1892

Clinical - Urology

ESTRO 2025

Results: The median follow-up was 24.7 months (0.8 – 94.4 months). For acute GU toxicity, moderate dose regions were predictive for grade 1-2 toxicity, while high-dose regions were more associated with grade 3-4 toxicity. Regions with moderate to high doses were predictive of late GU toxicity. For GI toxicity, moderate dose regions were important for both acute and late toxicity. For bladder, D15 cc< 26.3 Gy, D10%<19.08 Gy, and D1%<35.4 Gy were recommended to reduce acute GU toxicity. For rectum, V18 Gy<23.02% and V18.12 Gy<22.8% thresholds were recommended to minimize acute GI toxicity. To prevent late GI toxicity, V28 Gy< 9.6% was recommended (Figure 2). The HU protocol encompassed all significant dosimetric factors influencing toxicity outcomes. The median prostate volume was 51.89 cc (range, 19.21 – 124.76) and a prostate volume threshold of 60 cc was predictive of acute grade 3-4 GU toxicity.