Rationale for Utilization of Hydrogel Rectal Spacers in Dose Escalated SBRT for the Treatment of Unfavorable Risk Prostate Cancer

Repka, Michael C.; Creswell, Michael; Lischalk, Jonathan W.; Carrasquilla, Michael; Forsthoefel, Matthew; Lee, Jacqueline; Lei, Siyuan; Aghdam, Nima; Kataria, Shaan; Obayomi-Davies, Olusola; Collins, Brian T.; Suy, Simeng; Hankins, Ryan; Collins, Sean P.

doi:10.3389/fonc.2022.860848

Cited by 5 publications

(3 citation statements)

References 61 publications

(65 reference statements)

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“…However, the corresponding evidence for HA spacers rather than hydrogel spacers in post-SBRT clinical outcomes is relatively sparse. Recently, Repka et al outlined a framework and rationale for the utilization of rectal spacers in unfavorable-risk prostate cancer with dose-escalated SBRT [ 25 ].…”

Section: Discussionmentioning

confidence: 99%

One-year clinical outcomes of MR-guided stereotactic body radiation therapy with rectal spacer for patients with localized prostate cancer

Poon,

Yuan,

Wong

et al. 2024

World J Urol

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Background and purpose This prospective study aimed to investigate adaptive magnetic resonance (MR)-guided stereotactic body radiation therapy (MRgSBRT) with rectal spacer for localized prostate cancer (PC) and report 1-year clinical outcomes. Materials and methods Thirty-four consecutive patients with low- to high-risk localized PC that underwent 5-fraction adaptive MRgSBRT with rectal spacer were enrolled. The dosimetric comparison was performed on a risk- and age-matched cohort treated with MRgSBRT but without a spacer at a similar timepoint. Clinician-reported outcomes were based on Common Terminology Criteria for Adverse Events. Patient-reported outcomes were based on the Expanded Prostate Cancer Index Composite (EPIC) questionnaire at baseline, acute (1–3 months), subacute (4–12 months), and late (> 12 months) phases. Results The median follow-up was 390 days (range 28–823) and the median age was 70 years (range 58–82). One patient experienced rectal bleeding soon after spacer insertion that subsided before MRgSBRT. The median distance between the midline of the prostate midgland and the rectum after spacer insertion measured 7.8 mm (range 2.6–15.3), and the median length of the spacer was 45.9 mm (range 16.8–62.9) based on T2-weighted MR imaging. The use of spacer resulted in significant improvements in target coverage (V100% > 95% = 98.6% [range 93.4–99.8] for spacer vs. 97.8% [range 69.6–99.7] for non-spacer) and rectal sparing (V95% < 3 cc = 0.7 cc [range 0–4.6] for spacer vs. 4.9 cc [range 0–12.5] for non-spacer). Nine patients (26.5%) experienced grade 1 gastrointestinal toxicities, and no grade ≥ 2 toxicities were observed. During the 1-year follow-up period, EPIC scores for the bowel domain remained stable and were the highest among all other domains. Conclusions MRgSBRT with rectal spacer for localized PC showed exceptional tolerability with minimal gastrointestinal toxicities and satisfactory patient-reported outcomes. Improvements in dosimetry, rectal sparing, and target coverage were achieved with a rectal spacer. Randomized trials are warranted for further validation.

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Section: Discussionmentioning

confidence: 99%

One-year clinical outcomes of MR-guided stereotactic body radiation therapy with rectal spacer for patients with localized prostate cancer

Poon,

Yuan,

Wong

et al. 2024

World J Urol

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“…Patients with a history of pelvic surgery or pelvic radiation, which can cause significant scar tissue is another relative contraindication to hydrogel placement. Mahal et al demonstrated that adequate separation between the prostate and the rectum could be achieved with hydrogel placement in previously irradiated prostate cancer patients [ 43 ]. Compared to the average of 12.0 mm in patients with no radiation, there was a separation measuring 10.9 mm in patients with prior EBRT and a separation of 7.7 mm for patients with prior brachytherapy [ 43 ].…”

Section: Contraindications To Hydrogel Placementmentioning

confidence: 99%

“…Mahal et al demonstrated that adequate separation between the prostate and the rectum could be achieved with hydrogel placement in previously irradiated prostate cancer patients [ 43 ]. Compared to the average of 12.0 mm in patients with no radiation, there was a separation measuring 10.9 mm in patients with prior EBRT and a separation of 7.7 mm for patients with prior brachytherapy [ 43 ]. Thus, spacer injection can be considered in patients with a history of pelvic radiation at the discretion of the physician; however, further investigation/evidence would be beneficial in making this determination.…”

Section: Contraindications To Hydrogel Placementmentioning

confidence: 99%

Application of Hydrogel Spacer SpaceOAR Vue for Prostate Radiotherapy

Hadigal

Gupta

2022

Tomography

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Damage in the surrounding structures, including the rectum, due to unintended exposure to radiation is a large burden to bear for patients who undergo radiation therapy for prostate cancer. The use of injectable rectal spacers to distance the anterior rectum from the prostate is a potential strategy to reduce the dose of unintended radiation to the rectum. Hydrogel spacers are gaining increasing popularity in the treatment regimen for prostate cancer. After FDA approval of SpaceOAR, specialists are receiving an increasing number of referrals for hydrogel placements. In this paper, we review hydrogel spacers, the supporting clinical data, the best practices for hydrogel placement, and the risk of adverse events.

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Transient, Image‐Guided Gel‐Dissection for Percutaneous Thermal Ablation

Liu,

Russo,

Ellis

et al. 2024

Adv Healthcare Materials

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Image‐guided tumor ablative therapies are mainstay cancer treatment options, but often require intra‐procedural protective tissue displacement to reduce the risk of collateral damage to neighboring organs. Standard of care (SoC) strategies, such as hydrodissection (fluidic injection), are limited by rapid diffusion of fluid and poor retention time, risking injury to adjacent organs, increased cancer recurrence rates from incomplete tumor ablations, and limited patient qualification. Herein, we developed “gel‐dissection,” a technique leveraging injectable hydrogels for longer‐lasting, shapeable, and transient tissue separation, empowering clinicians with improved ablation operation windows and greater control. A rheological model was designed to understand and tune gel‐dissection parameters. In swine models, gel‐dissection achieved 24 times longer‐lasting tissue separation dynamics compared to saline, with 40% less injected volume. Gel‐dissection achieved anti‐dependent dissection between free‐floating organs in the peritoneal cavity and clinically significant thermal protection, with the potential to expand minimally invasive therapeutic techniques, especially across locoregional therapies including radiation, cryoablation, endoscopy, and surgery.This article is protected by copyright. All rights reserved

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Rationale for Utilization of Hydrogel Rectal Spacers in Dose Escalated SBRT for the Treatment of Unfavorable Risk Prostate Cancer

Cited by 5 publications

References 61 publications

One-year clinical outcomes of MR-guided stereotactic body radiation therapy with rectal spacer for patients with localized prostate cancer

One-year clinical outcomes of MR-guided stereotactic body radiation therapy with rectal spacer for patients with localized prostate cancer

Application of Hydrogel Spacer SpaceOAR Vue for Prostate Radiotherapy

Transient, Image‐Guided Gel‐Dissection for Percutaneous Thermal Ablation

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