ESTRO 2022 - Abstract Book

S1164

Abstract book

ESTRO 2022

Results Median follow-up was 22 (3-47) months. For acute and late toxicities see table 2. One (1.4%) late G3 GU toxicity occurred in a patient treated with 36.25 Gy (transurethral incision). Median post-SBRT PSA level was 0.370 (0,001-98.92) ng/ml. At the last follow up 3 pts died due to a non-cancer related cause, 4 pts had a biochemical failure with PSMA/Choline-PET positive progression: 3 treated to 36.25 Gy and 1 treated to 38 Gy. Two-year bRFS rates were 94.8% and 88,9% for pts treated with 36.25Gy and 38Gy, respectively (p= 0.6). OS rate was 96.7% at 2 years. DFS was 94.8% and 88.9%, respectively (p=0.6).

Conclusion Urethral sparing technique allowed dose escalation (from EQD2 91 Gy to EQD2 ≥ 120 Gy with α / β 1.5) without increasing G3 toxicity and with not inferior bRFS despite less ADT prescription. Longer follow-up is needed to confirm these results.

PO-1373 Inter-fraction variability of rectum/bladder volumes and doses based on daily CBCT imaging

T. Henry 1,2 , N. Pettersson 1,2 , U. Lindencrona 1,2 , A. Kyriakogiannaki 3,4 , A. Giouroukou 3,4 , J. Kindblom 3,4 , K. Braide 3,4

1 Region Västra Götaland, Sahlgrenska University Hospital, Dept of Medical Physics and Biomedical Engineering, Gothenburg, Sweden; 2 Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Department of Medical Radiation Sciences, Gothenburg, Sweden; 3 Region Västra Götaland, Sahlgrenska University Hospital, Dept of Oncology, Gothenburg, Sweden; 4 Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Department of Oncology, Gothenburg, Sweden