ESTRO 2022 - Abstract Book

S508

Abstract book

ESTRO 2022

Conclusion The UHF treatment scheme with HDR BB seems to be significantly better tolerated at multiple FU time point compared to the control treatment arms and saves 10 to 15 days in treatment time. Given the short FU, UHF seemingly provides similar BRFS, if not superior to control groups. Therefore, we will pursue accrual to our phase 2 study.

PD-0580 Assessment of acute toxicity with HDR focal boost and whole gland SBRT in localised prostate cancer

J. Padayachee 1 , Z. Liu 2 , A. Berlin 2 , J. Helou 2 , J. Winter 2 , V. Kong 1 , R. Glicksman 1 , S. Raman 1 , R. Weersink 2 , P. Chung 2

1 Princess Margaret Cancer Centre, Radiation Medicine Program, Toronto, Canada; 2 Princess Margaret Cancer Centre, Radiation Medicine Program, Toronto , Canada Purpose or Objective The dominant intraprostatic lesion (or GTV) may confer radioresistance leading to potential biochemical and clinical relapse following prostate radiotherapy. We evaluated an approach of HDR focal boost to the GTV followed by dose-adjusted whole gland SBRT, and herein report acute toxicity and early quality of life (QoL). Materials and Methods Patients with intermediate- to high-risk localised prostate cancer with MR identified GTV(s) were enrolled into this non- randomised phase II trial. All patients received MR-guided HDR focal boost to the GTV(s), 15 Gy in single fraction and whole