Oral & Poster Presentations Archive

UK & Ireland Prostate Brachytherapy Conference 2022

Abstract number 4 

A retrospective study looking at Rectal and Urethral dose delivered following Low Dose Rate Prostate Brachytherapy with and without a pre-rectal hydrogel (SpaceOAR) 

Sarveswaran G, Zuber S, Emmens D, Hodgkinson S, Brulinski P, Edwards A
Kent Oncology Centre, Maidstone 

PURPOSE: Retrospective analysis of dose data to assess the change in rectal and urethral dose following Low Dose Rate (LDR) Prostate brachytherapy using biodegradable pre-rectal hydrogel (SpaceOAR) at Kent Oncology Centre between October 2020 and December 2021 to ensure that there was no increase in urethral dose and demonstrate a reduction in rectal dose following insertion. 

METHODS: Patients at high risk of late rectal toxicity were had SpaceOAR inserted following LDR Brachytherapy implant. Records were retrospectively reviewed on a prospectively maintained database. Rectal and urethral doses were analysed from the final implant plant and the post implant CT. Bladder and bowel toxicity were graded at 3 months and 12 months after treatment using CTCAE criteria and patients were sent a PROMs questionnaire. 

RESULTS: 90 patients underwent LDR brachytherapy implant. 45 patients were deemed to be at higher risk of late bowel toxicity and had a SpaceOAR inserted following their implant. The mean Rectal V100 (< 2.0cc objective) and Urethral D30 at the end of implant (before SpaceOAR) was similar between the two groups; Rectal V100 1.18cc (0.25 – 2.0) no SpaceOAR vs 1.11cc (0.0 -2.25) with Space OAR, Urethral D30 176.56Gy (160.77 – 192.32) no SpaceOAR vs 178.17Gy (165.30-189.82). Data from patient Day 0 post implant CT demonstrates a reduction in the Rectal D2.0cc with the insertion of SpaceOAR; 97Gy (41.8 – 174.4) no SpaceOAR 65.8Gy (28.2 – 108.9) with SpaceOAR. There was no significant difference in the post implant CT Urethral D30 160.30 Gy vs 157.5Gy. 

CONCLUSION: This retrospective planning study confirms that a Pre-rectal hydrogel inserted following LDR Prostate Brachytherapy reduces the dose delivered to the rectum without increasing the urethral dose. No significant rectal symptoms were reported by patients in either group. We feel that a pre-rectal hydrogel should be considered in patients with high risk of bowel toxicity.