ESTRO 2025 - Abstract Book

S2138

Clinical - Urology

ESTRO 2025

(69.2%), 14 (21.5%), 2 (3.1%), 3 (4.6%), and 1 (1.5%) case, respectively. SYM score was associated with rectal V40 (p = 0.007) (figure 2).

Rectal toxicity G1- 2 occurred in 27.7% of patients (no ≥G3). Rectal toxicity incidence was associated with SQS score (p = 0.013), while no correlation with RWI categories was detected (p = 0.837).

Conclusion: For prostate cancer SBRT, hydrogel spacer placement was safe and high quality distribution scores correlate with improvement in rectal dose sparing and with reduced toxicity.

Keywords: hydrogel rectal spacer, SBRT, prostate cancer