ESTRO 2024 - Abstract Book

S2301

Clinical - Urology

ESTRO 2024

when compared to those without a spacer, with a reduction at V18 of 27.08%, V29 of 75.72% and V36 of 90.8% (Graph 1).

Toxicity rates were compared for both groups (Graph 2). For those with a spacer, acute gastrointestinal toxicity was most common after the second week of treatment, with 6 patients reporting symptoms of diarrhoea and proctitis. No patients experienced grade 3 CTCAE toxicity. For patients without a spacer, acute gastrointestinal toxicity was most common after the first week post treatment with 14 patient reporting grade 1-2 GI toxicity, decreasing to 11 patients the second week and 6 patients at six weeks from start of SABR. The most common acute toxicity was proctitis followed by diarrhoea. No patients without a spacer inserted experienced grade 3 CTCAE toxicity.

Graph 1. Mean rectal volume dose for patients with and without spacer

Graph 2. Acute Gastrointestinal toxicity for SABR patients with spacer graded using CTCAE version 5.1