ESTRO 2025 - Abstract Book

S1264

Clinical – Lower GI

ESTRO 2025

at the EoT which resolved to baseline levels by 6-weeks or 6-months in both arms (Figure 1). At 36-months, all patients had QOL scores from QLQ-C30 which were better or as good as general UK population norm data. At 36 months bowel function was good in both arms (sd-IMRT: mean 71.6 (SD 23.9); rd-IMRT: 75.9 (20.5)) and patients reported mild levels of urinary frequency (sd-IMRT: 26.1 (30.6); rd-IMRT: 31.6 (31.1)). Sexual function improved to baseline by 6-weeks for male and 6-months for female patients following rd-IMRT; by 36-months, male and female patients reported a moderate reduction in sexual function from baseline. Following sd-IMRT, large to moderate deteriorations in sexual function scores at EoT continued out to 36-months for both male and female patients.

Conclusion: Acute toxicity was lower with rd-IMRT. Late toxicity is similar, with a trend toward better bowel and sexual function following rd-IMRT, with patients reporting excellent long-term QOL. This is the first RCT globally to report using